Android UI 之 RecyclerView 基础用法
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基础用法
添加依赖
// RecyclerAdapter
implementation 'com.github.CymChad:BaseRecyclerViewAdapterHelper:2.9.30'
// glide
implementation 'com.github.bumptech.glide:glide:4.8.0';
-
效果图
-
布局文件
activity_fruit.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".ui.FruitActivity">
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/rv_fruit"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
item_fruit
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="60dp">
<ImageView
android:id="@+id/iv_fruit"
android:layout_width="45dp"
android:layout_height="45dp"
android:layout_gravity="center_vertical"
android:src="@mipmap/ic_apple"/>
<TextView
android:id="@+id/tv_fruit_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginLeft="10dp"/>
</LinearLayout>
- 分隔线
public class RecyclerViewDivider extends RecyclerView.ItemDecoration {
private static final String TAG = "RecyclerViewDivider";
private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
private static final int DIVIDER_COLOR = Color.parseColor("#efefef");
private Paint mPaint;
private Drawable mDivider;
private int mDividerHeight = 1;
//The direction of the list：LinearLayoutManager.VERTICAL or LinearLayoutManager.HORIZONTAL
private int mOrientation;
private int mLeftOffset;
private int mRightOffset;
private boolean mIsShowLastDivider;
private int mDividerColor;
private int mStart = 0;
private int mEnd = 0;
public RecyclerViewDivider(Context context) {
this(context, LinearLayoutManager.VERTICAL, 1, DIVIDER_COLOR);
}
public RecyclerViewDivider(Context context, int orientation, int dividerHeight, int dividerColor) {
this(context, orientation);
mDividerColor = dividerColor;
mDividerHeight = dividerHeight;
mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mPaint.setColor(dividerColor);
mPaint.setStyle(Paint.Style.FILL);
}
public RecyclerViewDivider(Context context, int orientation) {
if (orientation != LinearLayoutManager.VERTICAL
&& orientation != LinearLayoutManager.HORIZONTAL) {
throw new IllegalArgumentException("Please input right parameter");
}
mOrientation = orientation;
final TypedArray a = context.obtainStyledAttributes(ATTRS);
mDivider = a.getDrawable(0);
a.recycle();
}
public RecyclerViewDivider(Context context, int orientation, int drawableId) {
this(context, orientation);
mDivider = ContextCompat.getDrawable(context, drawableId);
mDividerHeight = mDivider.getIntrinsicHeight();
}
/**
* Set the offset of the horizontal split line
*
* @param leftOffset
* @param rightOffset
*/
public void setHorizontaloffset(int leftOffset, int rightOffset) {
mLeftOffset = leftOffset;
mRightOffset = rightOffset;
}
/**
* Set whether to display the last split line, not displayed by default
*
* @param isShowLastDivider
*/
public void setShowLastDivider(boolean isShowLastDivider) {
mIsShowLastDivider = isShowLastDivider;
}
/**
* split line display range
* <p>
* fisrt = 0 + start;
* last = childSize - 1 - end - mIsShowLastDivider ? 0 : 1
*
* @param start
* @param end
*/
public void setDividerStartAndEndOffsetCount(int start, int end) {
mStart = start;
mEnd = end;
}
public void setDividerHeight(int dividerHeight) {
mDividerHeight = dividerHeight;
}
public void setDividerColor(int dividerColor) {
mDividerColor = dividerColor;
if (mPaint != null) {
mPaint.setColor(mDividerColor);
}
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
outRect.set(0, 0, 0, mDividerHeight);
}
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
super.onDraw(c, parent, state);
if (mOrientation == LinearLayoutManager.VERTICAL) {
drawVerticalDivider(c, parent);
} else {
drawHorizontalDivider(c, parent);
}
}
//Draw item dividing line
private void drawVerticalDivider(Canvas canvas, RecyclerView parent) {
// mLeftOffset 为自己设置的左边偏移量
final int left = parent.getPaddingLeft() + mLeftOffset;
// mRightOffset 为设置的右边偏移量
final int right = parent.getMeasuredWidth() - parent.getPaddingRight() + mRightOffset;
final int childSize = parent.getChildCount();
if (childSize <= 0) {
return;
}
// 从第一个 item 开始绘制
int first = mStart;
// 到第几个 item 绘制结束
int last = childSize - mEnd - (mIsShowLastDivider ? 0 : 1);
Log.d(TAG, " last = " + last + " childSize =" + childSize + "left = " + left);
if (last <= 0) {
return;
}
for (int i = first; i < last; i++) {
drawableVerticalDivider(canvas, parent, left, right, i, mDividerHeight);
}
}
private void drawableVerticalDivider(Canvas canvas, RecyclerView parent, int left, int right, int i, int dividerHeight) {
final View child = parent.getChildAt(i);
if (child == null) {
return;
}
RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
final int top = child.getBottom() + layoutParams.bottomMargin;
final int bottom = top + dividerHeight;
// 适配 drawable
if (mDivider != null) {
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(canvas);
}
// 适配分割线
if (mPaint != null) {
canvas.drawRect(left, top, right, bottom, mPaint);
}
}
// Draw vertical item dividing line
private void drawHorizontalDivider(Canvas canvas, RecyclerView parent) {
final int top = parent.getPaddingTop();
final int bottom = parent.getMeasuredHeight() - parent.getPaddingBottom();
final int childSize = parent.getChildCount();
for (int i = 0; i < childSize; i++) {
final View child = parent.getChildAt(i);
RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
final int left = child.getRight() + layoutParams.rightMargin;
final int right = left + mDividerHeight;
if (mDivider != null) {
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(canvas);
}
if (mPaint != null) {
canvas.drawRect(left, top, right, bottom, mPaint);
}
}
}
}
- 适配器
public class FruitAdapter extends BaseQuickAdapter<FruitBean, BaseViewHolder> {
public FruitAdapter(int layoutResId, @Nullable List<FruitBean> data) {
super(layoutResId, data);
}
@Override
protected void convert(BaseViewHolder helper, FruitBean item) {
ImageView image = helper.getView(R.id.iv_fruit);
Glide.with(MyApp.getAppContext())
.load(item.getIconId())
.into(image);
helper.setText(R.id.tv_fruit_name,item.getName());
}
}
- 逻辑代码
public class FruitActivity extends BaseActivity {
@BindView(R.id.rv_fruit)
RecyclerView mRecyclerView;
private FruitAdapter mAdapter;
@Override
public int getLayoutId() {
return R.layout.activity_fruit;
}
@Override
public void initView() {
mAdapter = new FruitAdapter(R.layout.item_fruit,getData());
mAdapter.openLoadAnimation();
RecyclerViewDivider recyclerViewDivider = new RecyclerViewDivider(this);
recyclerViewDivider.setHorizontaloffset(DensityUtil.dip2px(this, 15), 0);
recyclerViewDivider.setDividerColor(Color.GRAY);
recyclerViewDivider.setDividerHeight(DensityUtil.dip2px(this, 0.5f));
mRecyclerView.addItemDecoration(recyclerViewDivider);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(layoutManager);
mRecyclerView.setAdapter(mAdapter);
}
private List<FruitBean> getData() {
return Arrays.asList(new FruitBean("apple",R.mipmap.ic_apple),
new FruitBean("banana",R.mipmap.ic_banana),
new FruitBean("cherry",R.mipmap.ic_cherry),
new FruitBean("grape",R.mipmap.ic_grape),
new FruitBean("mango",R.mipmap.ic_mango),
new FruitBean("orange",R.mipmap.ic_orange),
new FruitBean("pear",R.mipmap.ic_pear),
new FruitBean("pineapple",R.mipmap.ic_pineapple),
new FruitBean("watermelon",R.mipmap.ic_watermelon),
new FruitBean("strawberry",R.mipmap.ic_strawberry)
);
}
}
- 工具类
public class DensityUtil {
private static int[] deviceWidthHeight = new int[2];
public static int[] getDeviceInfo(Context context) {
if ((deviceWidthHeight[0] == 0) && (deviceWidthHeight[1] == 0)) {
DisplayMetrics metrics = new DisplayMetrics();
((Activity) context).getWindowManager().getDefaultDisplay()
.getMetrics(metrics);
deviceWidthHeight[0] = metrics.widthPixels;
deviceWidthHeight[1] = metrics.heightPixels;
}
return deviceWidthHeight;
}
/**
*
* @param context 上下文
* @param dpValue dp数值
* @return dp to px
*/
public static int dip2px(Context context, float dpValue) {
final float scale = context.getResources().getDisplayMetrics().density;
return (int) (dpValue * scale + 0.5f);
}
/**
* 获取屏幕尺寸
*/
@SuppressWarnings("deprecation")
@TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)
public static Point getScreenSize(Context context){
WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
Display display = windowManager.getDefaultDisplay();
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Android UI 之 RecyclerView 基础用法