button 与 switchbutton 有啥区别吗?
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如题,小弟目前只知道button可自定义鼠标左,中,右的动作,好像button实现的功能多,实在不知switchbutton有什么用,它有哪些优势呢?弄成抽屉菜单,参考高手的配置,有些是frame+switchbutton实现的,有些是frame+button小弟愚钝,请高手指教!如有教程,可附上,感谢!
switchbutton 是状态控制用的不管怎麽点他 他都只有两个状态 点击他是切换状态比如用他绑定天气插件 点一下 显示天气 再点一下 隐藏天气 (frame+switchbutton)frame+button 的话 就可以做成 左键显示 右键隐藏 这类的 参考技术A 谢谢楼上解释。。。我以为是编程里的按钮和图片按钮。滑动的Button
在介绍SwitchButton之前,先来看一下系统Button是如何实现的。源码如下:
- @RemoteView
- public class Button extends TextView {
- public Button(Context context) {
- this(context, null);
- }
- public Button(Context context, AttributeSet attrs) {
- this(context, attrs, com.android.internal.R.attr.buttonStyle);
- }
- public Button(Context context, AttributeSet attrs, int defStyle) {
- super(context, attrs, defStyle);
- }
- @Override
- public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
- super.onInitializeAccessibilityEvent(event);
- event.setClassName(Button. class.getName());
- }
- @Override
- public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
- super.onInitializeAccessibilityNodeInfo(info);
- info.setClassName(Button. class.getName());
- }
- }
@RemoteView public class Button extends TextView { public Button(Context context) { this(context, null); } public Button(Context context, AttributeSet attrs) { this(context, attrs, com.android.internal.R.attr.buttonStyle); } public Button(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } @Override public void onInitializeAccessibilityEvent(AccessibilityEvent event) { super.onInitializeAccessibilityEvent(event); event.setClassName(Button. class.getName()); } @Override public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { super.onInitializeAccessibilityNodeInfo(info); info.setClassName(Button. class.getName()); } }
是直接继承于TextView,所不同的是在构造方法中添加了Button的样式,并且在初始化可见性方面交由Button类自己来处理。虽然Button的实现比较简单,但是它的子类并不是这样。看一下:
直接子类只有有一个,CompoundButton。它是一个抽象类,而实现这个类的控件正是CheckBox, RadioButton, Switch, ToggleButton这四个,所以先重点说一下它。源码如下:
- /**
- * <p>
- * A button with two states, checked and unchecked. When the button is pressed
- * or clicked, the state changes automatically.
- * </p>
- *
- * <p><strong>XML attributes </strong></p>
- * <p>
- * See {@link android.R.styleable#CompoundButton
- * CompoundButton Attributes}, {@link android.R.styleable#Button Button
- * Attributes}, {@link android.R.styleable#TextView TextView Attributes}, {@link
- * android.R.styleable #View View Attributes}
- * </p>
- */
- public abstract class CompoundButton extends Button implements Checkable {
- private boolean mChecked ;
- private int mButtonResource ;
- private boolean mBroadcasting ;
- private Drawable mButtonDrawable;
- private OnCheckedChangeListener mOnCheckedChangeListener;
- private OnCheckedChangeListener mOnCheckedChangeWidgetListener ;
- private static final int[] CHECKED_STATE_SET = {
- R.attr.state_checked
- };
- public CompoundButton(Context context) {
- this(context, null);
- }
- public CompoundButton(Context context, AttributeSet attrs) {
- this(context, attrs, 0);
- }
- public CompoundButton(Context context, AttributeSet attrs, int defStyle) {
- super(context, attrs, defStyle);
- TypedArray a =
- context.obtainStyledAttributes(
- attrs, com.android.internal.R.styleable.CompoundButton, defStyle, 0);
- Drawable d = a.getDrawable(com.android.internal.R.styleable.CompoundButton_button);
- if (d != null ) {
- setButtonDrawable(d);
- }
- boolean checked = a
- .getBoolean(com.android.internal.R.styleable.CompoundButton_checked, false);
- setChecked(checked);
- a.recycle();
- }
- public void toggle() {
- setChecked(! mChecked);
- }
- @Override
- public boolean performClick() {
- /*
- * XXX: These are tiny, need some surrounding ‘expanded touch area‘,
- * which will need to be implemented in Button if we only override
- * performClick()
- */
- /* When clicked, toggle the state */
- toggle();
- return super .performClick();
- }
- @ViewDebug.ExportedProperty
- public boolean isChecked() {
- return mChecked ;
- }
- /**
- * <p>Changes the checked state of this button.</p>
- *
- * @param checked true to check the button, false to uncheck it
- */
- public void setChecked(boolean checked) {
- if (mChecked != checked) {
- mChecked = checked;
- refreshDrawableState();
- notifyViewAccessibilityStateChangedIfNeeded(
- AccessibilityEvent.CONTENT_CHANGE_TYPE_UNDEFINED );
- // Avoid infinite recursions if setChecked() is called from a listener
- if (mBroadcasting ) {
- return;
- }
- mBroadcasting = true ;
- if (mOnCheckedChangeListener != null) {
- mOnCheckedChangeListener.onCheckedChanged(this, mChecked);
- }
- if (mOnCheckedChangeWidgetListener != null) {
- mOnCheckedChangeWidgetListener .onCheckedChanged(this, mChecked);
- }
- mBroadcasting = false ;
- }
- }
- /**
- * Register a callback to be invoked when the checked state of this button
- * changes.
- *
- * @param listener the callback to call on checked state change
- */
- public void setOnCheckedChangeListener(OnCheckedChangeListener listener) {
- mOnCheckedChangeListener = listener;
- }
- /**
- * Register a callback to be invoked when the checked state of this button
- * changes. This callback is used for internal purpose only.
- *
- * @param listener the callback to call on checked state change
- * @hide
- */
- void setOnCheckedChangeWidgetListener(OnCheckedChangeListener listener) {
- mOnCheckedChangeWidgetListener = listener;
- }
- /**
- * Interface definition for a callback to be invoked when the checked state
- * of a compound button changed.
- */
- public static interface OnCheckedChangeListener {
- /**
- * Called when the checked state of a compound button has changed.
- *
- * @param buttonView The compound button view whose state has changed.
- * @param isChecked The new checked state of buttonView.
- */
- void onCheckedChanged(CompoundButton buttonView, boolean isChecked);
- }
- /**
- * Set the background to a given Drawable, identified by its resource id.
- *
- * @param resid the resource id of the drawable to use as the background
- */
- public void setButtonDrawable(int resid) {
- if (resid != 0 && resid == mButtonResource ) {
- return;
- }
- mButtonResource = resid;
- Drawable d = null;
- if (mButtonResource != 0) {
- d = getResources().getDrawable(mButtonResource );
- }
- setButtonDrawable(d);
- }
- /**
- * Set the background to a given Drawable
- *
- * @param d The Drawable to use as the background
- */
- public void setButtonDrawable(Drawable d) {
- if (d != null ) {
- if (mButtonDrawable != null) {
- mButtonDrawable.setCallback(null);
- unscheduleDrawable( mButtonDrawable);
- }
- d.setCallback( this);
- d.setVisible(getVisibility() == VISIBLE, false);
- mButtonDrawable = d;
- setMinHeight(mButtonDrawable .getIntrinsicHeight());
- }
- refreshDrawableState();
- }
- @Override
- public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
- super.onInitializeAccessibilityEvent(event);
- event.setClassName(CompoundButton.class .getName());
- event.setChecked( mChecked);
- }
- @Override
- public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
- super.onInitializeAccessibilityNodeInfo(info);
- info.setClassName(CompoundButton.class .getName());
- info.setCheckable( true);
- info.setChecked( mChecked);
- }
- @Override
- public int getCompoundPaddingLeft() {
- int padding = super.getCompoundPaddingLeft();
- if (!isLayoutRtl()) {
- final Drawable buttonDrawable = mButtonDrawable;
- if (buttonDrawable != null) {
- padding += buttonDrawable.getIntrinsicWidth();
- }
- }
- return padding;
- }
- @Override
- public int getCompoundPaddingRight() {
- int padding = super.getCompoundPaddingRight();
- if (isLayoutRtl()) {
- final Drawable buttonDrawable = mButtonDrawable;
- if (buttonDrawable != null) {
- padding += buttonDrawable.getIntrinsicWidth();
- }
- }
- return padding;
- }
- /**
- * @hide
- */
- @Override
- public int getHorizontalOffsetForDrawables() {
- final Drawable buttonDrawable = mButtonDrawable ;
- return (buttonDrawable != null) ? buttonDrawable.getIntrinsicWidth() : 0;
- }
- @Override
- protected void onDraw(Canvas canvas) {
- super.onDraw(canvas);
- final Drawable buttonDrawable = mButtonDrawable ;
- if (buttonDrawable != null) {
- final int verticalGravity = getGravity() & Gravity.VERTICAL_GRAVITY_MASK ;
- final int drawableHeight = buttonDrawable.getIntrinsicHeight();
- final int drawableWidth = buttonDrawable.getIntrinsicWidth();
- int top = 0;
- switch (verticalGravity) {
- case Gravity.BOTTOM :
- top = getHeight() - drawableHeight;
- break;
- case Gravity.CENTER_VERTICAL :
- top = (getHeight() - drawableHeight) / 2;
- break;
- }
- int bottom = top + drawableHeight;
- int left = isLayoutRtl() ? getWidth() - drawableWidth : 0;
- int right = isLayoutRtl() ? getWidth() : drawableWidth;
- buttonDrawable.setBounds(left, top, right, bottom);
- buttonDrawable.draw(canvas);
- }
- }
- @Override
- protected int[] onCreateDrawableState(int extraSpace) {
- final int [] drawableState = super.onCreateDrawableState(extraSpace + 1);
- if (isChecked()) {
- mergeDrawableStates(drawableState, CHECKED_STATE_SET);
- }
- return drawableState;
- }
- @Override
- protected void drawableStateChanged() {
- super.drawableStateChanged();
- if (mButtonDrawable != null) {
- int[] myDrawableState = getDrawableState();
- // Set the state of the Drawable
- mButtonDrawable.setState(myDrawableState);
- invalidate();
- }
- }
- @Override
- protected boolean verifyDrawable(Drawable who) {
- return super .verifyDrawable(who) || who == mButtonDrawable;
- }
- @Override
- public void jumpDrawablesToCurrentState() {
- super.jumpDrawablesToCurrentState();
- if (mButtonDrawable != null) mButtonDrawable.jumpToCurrentState();
- }
- static class SavedState extends BaseSavedState {
- boolean checked ;
- /**
- * Constructor called from {@link CompoundButton#onSaveInstanceState()}
- */
- SavedState(Parcelable superState) {
- super(superState);
- }
- /**
- * Constructor called from {@link #CREATOR}
- */
- private SavedState(Parcel in) {
- super(in);
- checked = (Boolean)in.readValue( null);
- }
- @Override
- public void writeToParcel(Parcel out, int flags) {
- super.writeToParcel(out, flags);
- out.writeValue( checked);
- }
- @Override
- public String toString() {
- return "CompoundButton.SavedState{"
- + Integer.toHexString(System.identityHashCode(this))
- + " checked=" + checked + "}" ;
- }
- public static final Parcelable.Creator<SavedState> CREATOR
- = new Parcelable.Creator<SavedState>() {
- public SavedState createFromParcel(Parcel in) {
- return new SavedState(in);
- }
- public SavedState[] newArray(int size) {
- return new SavedState[size];
- }
- };
- }
- @Override
- public Parcelable onSaveInstanceState() {
- // Force our ancestor class to save its state
- setFreezesText( true);
- Parcelable superState = super.onSaveInstanceState();
- SavedState ss = new SavedState(superState);
- ss. checked = isChecked();
- return ss;
- }
- @Override
- public void onRestoreInstanceState(Parcelable state) {
- SavedState ss = (SavedState) state;
- super.onRestoreInstanceState(ss.getSuperState());
- setChecked(ss. checked);
- requestLayout();
- }
- }
/** * <p> * A button with two states, checked and unchecked. When the button is pressed * or clicked, the state changes automatically. * </p> * * <p><strong>XML attributes </strong></p> * <p> * See {@link android.R.styleable#CompoundButton * CompoundButton Attributes}, {@link android.R.styleable#Button Button * Attributes}, {@link android.R.styleable#TextView TextView Attributes}, {@link * android.R.styleable #View View Attributes} * </p> */ public abstract class CompoundButton extends Button implements Checkable { private boolean mChecked ; private int mButtonResource ; private boolean mBroadcasting ; private Drawable mButtonDrawable; private OnCheckedChangeListener mOnCheckedChangeListener; private OnCheckedChangeListener mOnCheckedChangeWidgetListener ; private static final int[] CHECKED_STATE_SET = { R.attr.state_checked }; public CompoundButton(Context context) { this(context, null); } public CompoundButton(Context context, AttributeSet attrs) { this(context, attrs, 0); } public CompoundButton(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); TypedArray a = context.obtainStyledAttributes( attrs, com.android.internal.R.styleable.CompoundButton, defStyle, 0); Drawable d = a.getDrawable(com.android.internal.R.styleable.CompoundButton_button); if (d != null ) { setButtonDrawable(d); } boolean checked = a .getBoolean(com.android.internal.R.styleable.CompoundButton_checked, false); setChecked(checked); a.recycle(); } public void toggle() { setChecked(! mChecked); } @Override public boolean performClick() { /* * XXX: These are tiny, need some surrounding ‘expanded touch area‘, * which will need to be implemented in Button if we only override * performClick() */ /* When clicked, toggle the state */ toggle(); return super .performClick(); } @ViewDebug.ExportedProperty public boolean isChecked() { return mChecked ; } /** * <p>Changes the checked state of this button.</p> * * @param checked true to check the button, false to uncheck it */ public void setChecked(boolean checked) { if (mChecked != checked) { mChecked = checked; refreshDrawableState(); notifyViewAccessibilityStateChangedIfNeeded( AccessibilityEvent.CONTENT_CHANGE_TYPE_UNDEFINED ); // Avoid infinite recursions if setChecked() is called from a listener if (mBroadcasting ) { return; } mBroadcasting = true ; if (mOnCheckedChangeListener != null) { mOnCheckedChangeListener.onCheckedChanged(this, mChecked); } if (mOnCheckedChangeWidgetListener != null) { mOnCheckedChangeWidgetListener .onCheckedChanged(this, mChecked); } mBroadcasting = false ; } } /** * Register a callback to be invoked when the checked state of this button * changes. * * @param listener the callback to call on checked state change */ public void setOnCheckedChangeListener(OnCheckedChangeListener listener) { mOnCheckedChangeListener = listener; } /** * Register a callback to be invoked when the checked state of this button * changes. This callback is used for internal purpose only. * * @param listener the callback to call on checked state change * @hide */ void setOnCheckedChangeWidgetListener(OnCheckedChangeListener listener) { mOnCheckedChangeWidgetListener = listener; } /** * Interface definition for a callback to be invoked when the checked state * of a compound button changed. */ public static interface OnCheckedChangeListener { /** * Called when the checked state of a compound button has changed. * * @param buttonView The compound button view whose state has changed. * @param isChecked The new checked state of buttonView. */ void onCheckedChanged(CompoundButton buttonView, boolean isChecked); } /** * Set the background to a given Drawable, identified by its resource id. * * @param resid the resource id of the drawable to use as the background */ public void setButtonDrawable(int resid) { if (resid != 0 && resid == mButtonResource ) { return; } mButtonResource = resid; Drawable d = null; if (mButtonResource != 0) { d = getResources().getDrawable(mButtonResource ); } setButtonDrawable(d); } /** * Set the background to a given Drawable * * @param d The Drawable to use as the background */ public void setButtonDrawable(Drawable d) { if (d != null ) { if (mButtonDrawable != null) { mButtonDrawable.setCallback(null); unscheduleDrawable( mButtonDrawable); } d.setCallback( this); d.setVisible(getVisibility() == VISIBLE, false); mButtonDrawable = d; setMinHeight(mButtonDrawable .getIntrinsicHeight()); } refreshDrawableState(); } @Override public void onInitializeAccessibilityEvent(AccessibilityEvent event) { super.onInitializeAccessibilityEvent(event); event.setClassName(CompoundButton.class .getName()); event.setChecked( mChecked); } @Override public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { super.onInitializeAccessibilityNodeInfo(info); info.setClassName(CompoundButton.class .getName()); info.setCheckable( true); info.setChecked( mChecked); } @Override public int getCompoundPaddingLeft() { int padding = super.getCompoundPaddingLeft(); if (!isLayoutRtl()) { final Drawable buttonDrawable = mButtonDrawable; if (buttonDrawable != null) { padding += buttonDrawable.getIntrinsicWidth(); } } return padding; } @Override public int getCompoundPaddingRight() { int padding = super.getCompoundPaddingRight(); if (isLayoutRtl()) { final Drawable buttonDrawable = mButtonDrawable; if (buttonDrawable != null) { padding += buttonDrawable.getIntrinsicWidth(); } } return padding; } /** * @hide */ @Override public int getHorizontalOffsetForDrawables() { final Drawable buttonDrawable = mButtonDrawable ; return (buttonDrawable != null) ? buttonDrawable.getIntrinsicWidth() : 0; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); final Drawable buttonDrawable = mButtonDrawable ; if (buttonDrawable != null) { final int verticalGravity = getGravity() & Gravity.VERTICAL_GRAVITY_MASK ; final int drawableHeight = buttonDrawable.getIntrinsicHeight(); final int drawableWidth = buttonDrawable.getIntrinsicWidth(); int top = 0; switch (verticalGravity) { case Gravity.BOTTOM : top = getHeight() - drawableHeight; break; case Gravity.CENTER_VERTICAL : top = (getHeight() - drawableHeight) / 2; break; } int bottom = top + drawableHeight; int left = isLayoutRtl() ? getWidth() - drawableWidth : 0; int right = isLayoutRtl() ? getWidth() : drawableWidth; buttonDrawable.setBounds(left, top, right, bottom); buttonDrawable.draw(canvas); } } @Override protected int[] onCreateDrawableState(int extraSpace) { final int [] drawableState = super.onCreateDrawableState(extraSpace + 1); if (isChecked()) { mergeDrawableStates(drawableState, CHECKED_STATE_SET); } return drawableState; } @Override protected void drawableStateChanged() { super.drawableStateChanged(); if (mButtonDrawable != null) { int[] myDrawableState = getDrawableState(); // Set the state of the Drawable mButtonDrawable.setState(myDrawableState); invalidate(); } } @Override protected boolean verifyDrawable(Drawable who) { return super .verifyDrawable(who) || who == mButtonDrawable; } @Override public void jumpDrawablesToCurrentState() { super.jumpDrawablesToCurrentState(); if (mButtonDrawable != null) mButtonDrawable.jumpToCurrentState(); } static class SavedState extends BaseSavedState { boolean checked ; /** * Constructor called from {@link CompoundButton#onSaveInstanceState()} */ SavedState(Parcelable superState) { super(superState); } /** * Constructor called from {@link #CREATOR} */ private SavedState(Parcel in) { super(in); checked = (Boolean)in.readValue( null); } @Override public void writeToParcel(Parcel out, int flags) { super.writeToParcel(out, flags); out.writeValue( checked); } @Override public String toString() { return "CompoundButton.SavedState{" + Integer.toHexString(System.identityHashCode(this)) + " checked=" + checked + "}" ; } public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() { public SavedState createFromParcel(Parcel in) { return new SavedState(in); } public SavedState[] newArray(int size) { return new SavedState[size]; } }; } @Override public Parcelable onSaveInstanceState() { // Force our ancestor class to save its state setFreezesText( true); Parcelable superState = super.onSaveInstanceState(); SavedState ss = new SavedState(superState); ss. checked = isChecked(); return ss; } @Override public void onRestoreInstanceState(Parcelable state) { SavedState ss = (SavedState) state; super.onRestoreInstanceState(ss.getSuperState()); setChecked(ss. checked); requestLayout(); } }先从构造方法开始,在构造方法中,
- public CompoundButton(Context context, AttributeSet attrs, int defStyle) {
- super(context, attrs, defStyle);
- TypedArray a =
- context.obtainStyledAttributes(
- attrs, com.android.internal.R.styleable.CompoundButton, defStyle, 0);
- Drawable d = a.getDrawable(com.android.internal.R.styleable.CompoundButton_button);
- if (d != null ) {
- setButtonDrawable(d);
- }
- boolean checked = a
- .getBoolean(com.android.internal.R.styleable.CompoundButton_checked, false);
- setChecked(checked);
- a.recycle();
- }
public CompoundButton(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); TypedArray a = context.obtainStyledAttributes( attrs, com.android.internal.R.styleable.CompoundButton, defStyle, 0); Drawable d = a.getDrawable(com.android.internal.R.styleable.CompoundButton_button); if (d != null ) { setButtonDrawable(d); } boolean checked = a .getBoolean(com.android.internal.R.styleable.CompoundButton_checked, false); setChecked(checked); a.recycle(); }先是从attrs中读取定义的属性,一个是Drawable用于设置背景;一个是布尔类型变量用于判断是否check过。设置背景使用的是setButtonDrawable()方法,代码如下:
- /**
- * Set the background to a given Drawable
- *
- * @param d The Drawable to use as the background
- */
- public void setButtonDrawable(Drawable d) {
- if (d != null ) {
- if (mButtonDrawable != null) {
- mButtonDrawable.setCallback(null);
- unscheduleDrawable( mButtonDrawable);
- }
- d.setCallback( this);
- d.setVisible(getVisibility() == VISIBLE, false);
- mButtonDrawable = d;
- setMinHeight(mButtonDrawable .getIntrinsicHeight());
- }
- refreshDrawableState();
- }
/** * Set the background to a given Drawable * * @param d The Drawable to use as the background */ public void setButtonDrawable(Drawable d) { if (d != null ) { if (mButtonDrawable != null) { mButtonDrawable.setCallback(null); unscheduleDrawable( mButtonDrawable); } d.setCallback( this); d.setVisible(getVisibility() == VISIBLE, false); mButtonDrawable = d; setMinHeight(mButtonDrawable .getIntrinsicHeight()); } refreshDrawableState(); }这个方法写的就比较完善,可以作为一个学习的典范。首先判断传递过来的Drawable是否为空,如果不为空并且默认的Drawable也不为空,那么取消默认Drawable的callback,然后调用unscheduleDrawable方法。这个方法代码如下:
- /**
- * Unschedule any events associated with the given Drawable. This can be
- * used when selecting a new Drawable into a view, so that the previous
- * one is completely unscheduled.
- *
- * @param who The Drawable to unschedule.
- *
- * @see #drawableStateChanged
- */
- public void unscheduleDrawable(Drawable who) {
- if (mAttachInfo != null && who != null) {
- mAttachInfo.mViewRootImpl .mChoreographer.removeCallbacks(
- Choreographer.CALLBACK_ANIMATION, null, who);
- }
- }
/** * Unschedule any events associated with the given Drawable. This can be * used when selecting a new Drawable into a view, so that the previous * one is completely unscheduled. * * @param who The Drawable to unschedule. * * @see #drawableStateChanged */ public void unscheduleDrawable(Drawable who) { if (mAttachInfo != null && who != null) { mAttachInfo.mViewRootImpl .mChoreographer.removeCallbacks( Choreographer.CALLBACK_ANIMATION, null, who); } }从方法注释中可以看出它的用途,正是更换Drawable时候使用的。接下来开始重新设置Drawable,包括回调、可见性、最小高度。最后调用refreshDrawableState()方法,这个是View类的方法,用于更新Drawable状态。
然后再回过头看一下setChecked(checked)方法,这个用于设置check,也就是button的点击状态。代码如下:
- /**
- * <p>Changes the checked state of this button.</p>
- *
- * @param checked true to check the button, false to uncheck it
- */
- public void setChecked( boolean checked) {
- if (mChecked != checked) {
- mChecked = checked;
- refreshDrawableState();
- notifyViewAccessibilityStateChangedIfNeeded(
- AccessibilityEvent.CONTENT_CHANGE_TYPE_UNDEFINED );
- // Avoid infinite recursions if setChecked() is called from a listener
- if (mBroadcasting ) {
- return;
- }
- mBroadcasting = true ;
- if (mOnCheckedChangeListener != null) {
- mOnCheckedChangeListener.onCheckedChanged(this, mChecked);
- }
- if (mOnCheckedChangeWidgetListener != null) {
- mOnCheckedChangeWidgetListener .onCheckedChanged(this, mChecked);
- }
- mBroadcasting = false ;
- }
- }
/** * <p>Changes the checked state of this button.</p> * * @param checked true to check the button, false to uncheck it */ public void setChecked( boolean checked) { if (mChecked != checked) { mChecked = checked; refreshDrawableState(); notifyViewAccessibilityStateChangedIfNeeded( AccessibilityEvent.CONTENT_CHANGE_TYPE_UNDEFINED ); // Avoid infinite recursions if setChecked() is called from a listener if (mBroadcasting ) { return; } mBroadcasting = true ; if (mOnCheckedChangeListener != null) { mOnCheckedChangeListener.onCheckedChanged(this, mChecked); } if (mOnCheckedChangeWidgetListener != null) { mOnCheckedChangeWidgetListener .onCheckedChanged(this, mChecked); } mBroadcasting = false ; } }
在这个方法中多出了一个接口,这个接口真是check的一个回调接口,代码如下:
- /**
- * Interface definition for a callback to be invoked when the checked state
- * of a compound button changed.
- */
- public static interface OnCheckedChangeListener {
- /**
- * Called when the checked state of a compound button has changed.
- *
- * @param buttonView The compound button view whose state has changed.
- * @param isChecked The new checked state of buttonView.
- */
- void onCheckedChanged(CompoundButton buttonView, boolean isChecked);
- }
/** * Interface definition for a callback to be invoked when the checked state * of a compound button changed. */ public static interface OnCheckedChangeListener { /** * Called when the checked state of a compound button has changed. * * @param buttonView The compound button view whose state has changed. * @param isChecked The new checked state of buttonView. */ void onCheckedChanged(CompoundButton buttonView, boolean isChecked); }
这种回调接口在Android中处处可见,之前的文章也有介绍过。但是在上面的方法,它使用了一个mBroadcasting变量,进而巧妙地避免了重复递归的问题,大家自己感受一下。
然后就是ondraw()方法了,把之前的drawable画出来。代码如下:
- @Override
- protected void onDraw(Canvas canvas) {
- super.onDraw(canvas);
- final Drawable buttonDrawable = mButtonDrawable ;
- if (buttonDrawable != null) {
- final int verticalGravity = getGravity() & Gravity.VERTICAL_GRAVITY_MASK ;
- final int drawableHeight = buttonDrawable.getIntrinsicHeight();
- final int drawableWidth = buttonDrawable.getIntrinsicWidth();
- int top = 0;
- switch (verticalGravity) {
- case Gravity.BOTTOM :
- top = getHeight() - drawableHeight;
- break;
- case Gravity.CENTER_VERTICAL :
- top = (getHeight() - drawableHeight) / 2;
- break;
- }
- int bottom = top + drawableHeight;
- int left = isLayoutRtl() ? getWidth() - drawableWidth : 0;
- int right = isLayoutRtl() ? getWidth() : drawableWidth;
- buttonDrawable.setBounds(left, top, right, bottom);
- buttonDrawable.draw(canvas);
- }
- }
@Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); final Drawable buttonDrawable = mButtonDrawable ; if (buttonDrawable != null) { final int verticalGravity = getGravity() & Gravity.VERTICAL_GRAVITY_MASK ; final int drawableHeight = buttonDrawable.getIntrinsicHeight(); final int drawableWidth = buttonDrawable.getIntrinsicWidth(); int top = 0; switch (verticalGravity) { case Gravity.BOTTOM : top = getHeight() - drawableHeight; break; case Gravity.CENTER_VERTICAL : top = (getHeight() - drawableHeight) / 2; break; } int bottom = top + drawableHeight; int left = isLayoutRtl() ? getWidth() - drawableWidth : 0; int right = isLayoutRtl() ? getWidth() : drawableWidth; buttonDrawable.setBounds(left, top, right, bottom); buttonDrawable.draw(canvas); } }
看得出来,在onDrawable()方法中,最主要的部分还是如何确定上下左右四个参数。确定完后就可以画出来了。但是,CompoundButton是一个抽象类,并不能直接使用,那看一下它的子类是如何实现的:
1、CheckBox
- public class CheckBox extends CompoundButton {
- public CheckBox(Context context) {
- this(context, null);
- }
- public CheckBox(Context context, AttributeSet attrs) {
- this(context, attrs, com.android.internal.R.attr.checkboxStyle);
- }
- public CheckBox(Context context, AttributeSet attrs, int defStyle) {
- super(context, attrs, defStyle);
- }
- @Override
- public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
- super.onInitializeAccessibilityEvent(event);
- event.setClassName(CheckBox. class.getName());
- }
- @Override
- public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
- super.onInitializeAccessibilityNodeInfo(info);
- info.setClassName(CheckBox. class.getName());
- }
- }
public class CheckBox extends CompoundButton { public CheckBox(Context context) { this(context, null); } public CheckBox(Context context, AttributeSet attrs) { this(context, attrs, com.android.internal.R.attr.checkboxStyle); } public CheckBox(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } @Override public void onInitializeAccessibilityEvent(AccessibilityEvent event) { super.onInitializeAccessibilityEvent(event); event.setClassName(CheckBox. class.getName()); } @Override public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { super.onInitializeAccessibilityNodeInfo(info); info.setClassName(CheckBox. class.getName()); } }
和Button的实现差不多,使用了一个自己的样式。并且也是重写了那两个方法。再来看一下RadioButton,
- public class RadioButton extends CompoundButton {
- public RadioButton(Context context) {
- this(context, null);
- }
- public RadioButton(Context context, AttributeSet attrs) {
- this(context, attrs, com.android.internal.R.attr.radioButtonStyle);
- }
- public RadioButton(Context context, AttributeSet attrs, int defStyle) {
- super(context, attrs, defStyle);
- }
- /**
- * {@inheritDoc}
- * <p>
- * If the radio button is already checked, this method will not toggle the radio button.
- */
- @Override
- public void toggle() {
- // we override to prevent toggle when the radio is already
- // checked (as opposed to check boxes widgets)
- if (!isChecked()) {
- super.toggle();
- }
- }
- @Override
- public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
- super.onInitializeAccessibilityEvent(event);
- event.setClassName(RadioButton. class.getName());
- }
- @Override
- public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
- super.onInitializeAccessibilityNodeInfo(info);
- info.setClassName(RadioButton. class.getName());
- }
- }
public class RadioButton extends CompoundButton { public RadioButton(Context context) { this(context, null); } public RadioButton(Context context, AttributeSet attrs) { this(context, attrs, com.android.internal.R.attr.radioButtonStyle); } public RadioButton(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } /** * {@inheritDoc} * <p> * If the radio button is already checked, this method will not toggle the radio button. */ @Override public void toggle() { // we override to prevent toggle when the radio is already // checked (as opposed to check boxes widgets) if (!isChecked()) { super.toggle(); } } @Override public void onInitializeAccessibilityEvent(AccessibilityEvent event) { super.onInitializeAccessibilityEvent(event); event.setClassName(RadioButton. class.getName()); } @Override public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { super.onInitializeAccessibilityNodeInfo(info); info.setClassName(RadioButton. class.getName()); } }和CheckBox实现差不多,区别在于多重写了一个方法,用于防止按钮被重复点击。另外还有ToggleButton以及Switch,前者实现也比较简单,后者稍微麻烦了一些,感兴趣可以自己分析。
最后切入正题,看看滑动Button要如何实现呢?首先看一下效果图:
图1-1
图1-2
图1-1所示的滑动Button实现的思路是这样的,背景图片有开和关的文字,一个按钮在其上面左右滑动,遮住相应的部分,使其在一个位置时候只能看到一个开关。
如图1-3,在实现的时候,先画一个开关背景图片只,然后在其上面画一个按钮,滑动开关的时候对上面的按钮进行处理即可。
准备:
1、按钮图片
2、背景图片
编码:
在自定义滑动按钮控件的时候,可以有多种选择,可以继承于Button,也可以继承于Button的子类,也可以继承于View类等。我们知道滑动按钮是一个很简单的控件,就是左右滑动改变显示内容,不需要其他的额外东西在里面,所以直接继承于View来实现即可。如果继承于系统的一些控件,那么有很多东西用不到,会造成浪费。
1、定义一个类继承于View,初始化构造方法,在构造方法中加载图片及其信息。
2、重写onMeasure()方法,计算控件的大小。
3、重写onTouchEvent()方法,对滑动事件进行判别处理。
4、定义接口,实现回调。
5、重写onDraw()方法,动态画出按钮。
代码如下:
- /**
- *
- */
- package com.kince.slidebutton;
- import android.content.Context;
- import android.graphics.Bitmap;
- import android.graphics.BitmapFactory;
- import android.graphics.Canvas;
- import android.util.AttributeSet;
- import android.util.Log;
- import android.view.MotionEvent;
- import android.view.View;
- /**
- * @author kince
- * @category 左右手势滑动button
- * @serial 1.0.0
- * @since 2014.5.17
- * @see http://blog.csdn.net/wangjinyu501
- *
- */
- public class SlideButton extends View {
- private Bitmap slideBitMap;// 滑动图片
- private Bitmap switchBitMap;// 背景图片
- private int slideBitMapWidth;// 滑动图片宽度
- private int switchBitMapWidth;// 背景图片宽度
- private int switchBitMapHeight;// 背景图片高度
- private boolean currentState;// 开关状态
- private boolean isSliding = false; // 是否正在滑动中
- private int currentX; // 当前开关的位置
- private OnToggleStateChangedListener mChangedListener;// 回调接口
- /**
- * @param context
- * 在java代码中直接调用使用此构造方法
- */
- public SlideButton(Context context) {
- this(context, null);
- // TODO Auto-generated constructor stub
- }
- /**
- * @param context
- * @param attrs
- * 在xml中使用要用到这个方法
- */
- public SlideButton(Context context, AttributeSet attrs) {
- this(context, attrs, 0);
- // TODO Auto-generated constructor stub
- }
- /**
- * @param context
- * @param attrs
- * @param defStyleAttr
- * 指定一个样式
- */
- public SlideButton(Context context, AttributeSet attrs, int defStyleAttr) {
- super(context, attrs, defStyleAttr);
- initBitmap();
- }
- /**
- * @category 加载背景图片以及开关图片 然后获取各自的宽高
- *
- */
- private void initBitmap() {
- // TODO Auto-generated method stub
- slideBitMap = BitmapFactory.decodeResource(getResources(),
- R.drawable.slide_button_background);
- switchBitMap = BitmapFactory.decodeResource(getResources(),
- R.drawable.switch_background);
- slideBitMapWidth = slideBitMap.getWidth();
- switchBitMapWidth = switchBitMap.getWidth();
- switchBitMapHeight = switchBitMap.getHeight();
- Log.i("switchBitMapWidth", switchBitMapWidth + "");
- }
- @Override
- protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
- // TODO Auto-generated method stub
- super.onMeasure(widthMeasureSpec, heightMeasureSpec);
- setMeasuredDimension(switchBitMapWidth, switchBitMapHeight);// 设置控件的宽高
- }
- @Override
- protected void onDraw(Canvas canvas) {
- // 绘制button背景图片
- canvas.drawBitmap(switchBitMap, 0, 0, null);
- // 绘制滑动开关
- if (isSliding) {// 如果当前状态是滑动中 则动态绘制开关
- int dis = currentX - slideBitMapWidth / 2;
- if (dis < 0) {
- dis = 0;
- } else if (dis > switchBitMapWidth - slideBitMapWidth) {
- dis = switchBitMapWidth - slideBitMapWidth;
- }
- canvas.drawBitmap(slideBitMap, dis, 0, null);
- } else {
- if (currentState) { // 绘制开关为开的状态
- canvas.drawBitmap(slideBitMap, switchBitMapWidth
- - slideBitMapWidth, 0, null);
- } else { // 绘制开关为关的状态
- canvas.drawBitmap(slideBitMap, 0, 0, null);
- }
- }
- super.onDraw(canvas);
- }
- @Override
- public boolean onTouchEvent(MotionEvent event) {
- // 手势识别 判断滑动方向
- int action = event.getAction();
- switch (action) {
- case MotionEvent.ACTION_DOWN:
- isSliding = true;
- currentX = (int) event.getX();
- break;
- case MotionEvent.ACTION_MOVE:
- currentX = (int) event.getX();
- Log.i("currentX", currentX + "");
- break;
- case MotionEvent.ACTION_UP:
- isSliding = false;
- int bgCenter = switchBitMapWidth / 2;
- boolean state = currentX > bgCenter; // 改变后的状态
- if (state != currentState && mChangedListener != null) {// 添加回调
- mChangedListener.onToggleStateChanged(state);
- }
- currentState = state;
- break;
- default:
- break;
- }
- invalidate();
- return true;
- }
- public OnToggleStateChangedListener getmChangedListener() {
- return mChangedListener;
- }
- public void setmChangedListener(
- OnToggleStateChangedListener mChangedListener) {
- this.mChangedListener = mChangedListener;
- }
- public boolean isToggleState() {
- return currentState;
- }
- public void setToggleState(boolean currentState) {
- this.currentState = currentState;
- }
- }
/** * */ package com.kince.slidebutton; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.view.View; /** * @author kince * @category 左右手势滑动button * @serial 1.0.0 * @since 2014.5.17 * @see http://blog.csdn.net/wangjinyu501 * */ public class SlideButton extends View { private Bitmap slideBitMap;// 滑动图片 private Bitmap switchBitMap;// 背景图片 private int slideBitMapWidth;// 滑动图片宽度 private int switchBitMapWidth;// 背景图片宽度 private int switchBitMapHeight;// 背景图片高度 private boolean currentState;// 开关状态 private boolean isSliding = false; // 是否正在滑动中 private int currentX; // 当前开关的位置 private OnToggleStateChangedListener mChangedListener;// 回调接口 /** * @param context * 在java代码中直接调用使用此构造方法 */ public SlideButton(Context context) { this(context, null); // TODO Auto-generated constructor stub } /** * @param context * @param attrs * 在xml中使用要用到这个方法 */ public SlideButton(Context context, AttributeSet attrs) { this(context, attrs, 0); // TODO Auto-generated constructor stub } /** * @param context * @param attrs * @param defStyleAttr * 指定一个样式 */ public SlideButton(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); initBitmap(); } /** * @category 加载背景图片以及开关图片 然后获取各自的宽高 * */ private void initBitmap() { // TODO Auto-generated method stub slideBitMap = BitmapFactory.decodeResource(getResources(), R.drawable.slide_button_background); switchBitMap = BitmapFactory.decodeResource(getResources(), R.drawable.switch_background); slideBitMapWidth = slideBitMap.getWidth(); switchBitMapWidth = switchBitMap.getWidth(); switchBitMapHeight = switchBitMap.getHeight(); Log.i("switchBitMapWidth", switchBitMapWidth + ""); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { // TODO Auto-generated method stub super.onMeasure(widthMeasureSpec, heightMeasureSpec); setMeasuredDimension(switchBitMapWidth, switchBitMapHeight);// 设置控件的宽高 } @Override protected void onDraw(Canvas canvas) { // 绘制button背景图片 canvas.drawBitmap(switchBitMap, 0, 0, null); // 绘制滑动开关 if (isSliding) {// 如果当前状态是滑动中 则动态绘制开关 int dis = currentX - slideBitMapWidth / 2; if (dis < 0) { dis = 0; } else if (dis > switchBitMapWidth - slideBitMapWidth) { dis = switchBitMapWidth - slideBitMapWidth; } canvas.drawBitmap(slideBitMap, dis, 0, null); } else { if (currentState) { // 绘制开关为开的状态 canvas.drawBitmap(slideBitMap, switchBitMapWidth - slideBitMapWidth, 0, null); } else { // 绘制开关为关的状态 canvas.drawBitmap(slideBitMap, 0, 0, null); } } super.onDraw(canvas); } @Override public boolean onTouchEvent(MotionEvent event) { // 手势识别 判断滑动方向 int action = event.getAction(); switch (action) { case MotionEvent.ACTION_DOWN: isSliding = true; currentX = (int) event.getX(); break; case MotionEvent.ACTION_MOVE: currentX = (int) event.getX(); Log.i("currentX", currentX + ""); break; case MotionEvent.ACTION_UP: isSliding = false; int bgCenter = switchBitMapWidth / 2; boolean state = currentX > bgCenter; // 改变后的状态 if (state != currentState && mChangedListener != null) {// 添加回调 mChangedListener.onToggleStateChanged(state); } currentState = state; break; default: break; } invalidate(); return true; } public OnToggleStateChangedListener getmChangedListener() { return mChangedListener; } public void setmChangedListener( OnToggleStateChangedListener mChangedListener) { this.mChangedListener = mChangedListener; } public boolean isToggleState() { return currentState; } public void setToggleState(boolean currentState) { this.currentState = currentState; } }回调接口,
- package com.kince.slidebutton;
- **
- * @author kince
- *
- */
- ublic interface OnToggleStateChangedListener {
- /**
- * @category
- * @param state
- */
- public void onToggleStateChanged(boolean state);
package com.kince.slidebutton; /** * @author kince * */ public interface OnToggleStateChangedListener { /** * @category * @param state */ public void onToggleStateChanged(boolean state); }Activity代码,
- package com.kince.slidebutton;
- import android.support.v7.app.ActionBarActivity;
- import android.support.v7.app.ActionBar;
- import android.support.v4.app.Fragment;
- import android.support.v4.app.FragmentActivity;
- import android.os.Bundle;
- import android.view.LayoutInflater;
- import android.view.Menu;
- import android.view.MenuItem;
- import android.view.View;
- import android.view.ViewGroup;
- import android.widget.Toast;
- import android.os.Build;
- public class MainActivity extends ActionBarActivity {
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- if (savedInstanceState == null) {
- getSupportFragmentManager().beginTransaction()
- .add(R.id.container, new PlaceholderFragment()).commit();
- }
- }
- @Override
- public boolean onCreateOptionsMenu(Menu menu) {
- // Inflate the menu; this adds items to the action bar if it is present.
- getMenuInflater().inflate(R.menu.main, menu);
- return true;
- }
- @Override
- public boolean onOptionsItemSelected(MenuItem item) {
- // Handle action bar item clicks here. The action bar will
- // automatically handle clicks on the Home/Up button, so long
- // as you specify a parent activity in AndroidManifest.xml.
- int id = item.getItemId();
- if (id == R.id.action_settings) {
- return true;
- }
- return super.onOptionsItemSelected(item);
- }
- /**
- * A placeholder fragment containing a simple view.
- */
- public static class PlaceholderFragment extends Fragment implements
- OnToggleStateChangedListener {
- private SlideButton slidebutton;
- public PlaceholderFragment() {
- }
- @Override
- public View onCreateView(LayoutInflater inflater, ViewGroup container,
- Bundle savedInstanceState) {
- View rootView = inflater.inflate(R.layout.fragment_main, container,
- false);
- slidebutton = (SlideButton) rootView.findViewById(R.id.slidebutton1);
- // 设置一下开关的状态
- slidebutton.setToggleState(true); // 设置开关的状态为打开
- slidebutton.setmChangedListener(this);
- return rootView;
- }
- @Override
- public void onToggleStateChanged(boolean state) {
- // TODO Auto-generated method stub
- FragmentActivity activity = getActivity();
- if (state) {
- Toast.makeText(activity, "开关打开", 0).show();
- } else {
- Toast.makeText(activity, "开关关闭", 0).show();
- }
- }
- }
- }
package com.kince.slidebutton; import android.support.v7.app.ActionBarActivity; import android.support.v7.app.ActionBar; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentActivity; import android.os.Bundle; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.Toast; import android.os.Build; public class MainActivity extends ActionBarActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); if (savedInstanceState == null) { getSupportFragmentManager().beginTransaction() .add(R.id.container, new PlaceholderFragment()).commit(); } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } /** * A placeholder fragment containing a simple view. */ public static class PlaceholderFragment extends Fragment implements OnToggleStateChangedListener { private SlideButton slidebutton; public PlaceholderFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_main, container, false); slidebutton = (SlideButton) rootView.findViewById(R.id.slidebutton1); // 设置一下开关的状态 slidebutton.setToggleState(true); // 设置开关的状态为打开 slidebutton.setmChangedListener(this); return rootView; } @Override public void onToggleStateChanged(boolean state) { // TODO Auto-generated method stub FragmentActivity activity = getActivity(); if (state) { Toast.makeText(activity, "开关打开", 0).show(); } else { Toast.makeText(activity, "开关关闭", 0).show(); } } } }未完待续。
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