ScrollView阻尼效果
Posted brucemengbm
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activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context="com.example.scrollviewdemo.MainActivity" > <com.example.scrollviewdemo.CustomScrollView android:id="@+id/scrollview" android:layout_width="fill_parent" android:layout_height="fill_parent" > <LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <TextView android:layout_width="fill_parent" android:layout_height="100dp" android:text="AAA" > </TextView> <TextView android:layout_width="fill_parent" android:layout_height="100dp" android:text="AAA" > </TextView> <TextView android:layout_width="fill_parent" android:layout_height="100dp" android:text="AAA" > </TextView> <TextView android:layout_width="fill_parent" android:layout_height="100dp" android:text="AAA" > </TextView> <TextView android:layout_width="fill_parent" android:layout_height="100dp" android:text="AAA" > </TextView> <TextView android:layout_width="fill_parent" android:layout_height="100dp" android:text="AAA" > </TextView> <TextView android:layout_width="fill_parent" android:layout_height="100dp" android:text="AAA" > </TextView> <TextView android:layout_width="fill_parent" android:layout_height="100dp" android:text="AAA" > </TextView> <TextView android:layout_width="fill_parent" android:layout_height="100dp" android:text="AAA" > </TextView> </LinearLayout> </com.example.scrollviewdemo.CustomScrollView > </LinearLayout>
MainActivity
package com.example.scrollviewdemo;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ScrollView;
public class MainActivity extends Activity {
ScrollView scrollView;
private static final int TOUCH_EVENT_ID = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
scrollView = (ScrollView) findViewById(R.id.scrollview);
}
}方式一
ElasticScrollView
package com.example.scrollviewdemo;
import android.annotation.SuppressLint;
import android.content.Context;
import android.util.AttributeSet;
import android.widget.ScrollView;
import android.graphics.Rect;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.TranslateAnimation;
public class ElasticScrollView extends ScrollView {
//scrollView下的控件
private View inner;
private float y;
//保存状态的矩形框
private Rect normal = new Rect();
//是否要计算
private boolean isCount = false;
@SuppressLint("NewApi")
public ElasticScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
//载入完布局文件之后调用
@Override
protected void onFinishInflate() {
if (getChildCount() > 0) {
//获取控件
inner = getChildAt(0);
}
}
@SuppressLint("ClickableViewAccessibility")
@Override
public boolean onTouchEvent(MotionEvent ev) {
if (inner != null) {
commOnTouchEvent(ev);
}
return super.onTouchEvent(ev);
}
//处理触摸事件
public void commOnTouchEvent(MotionEvent ev) {
int action = ev.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
break;
case MotionEvent.ACTION_UP:
//是不是须要动画
if (isNeedAnimation()) {
animation();
isCount = false;
}
break;
case MotionEvent.ACTION_MOVE:
final float preY = y;
float nowY = ev.getY();
int deltaY = (int) (preY - nowY);
if (!isCount) {
deltaY = 0;
}
y = nowY;
if (isNeedMove()) {
if (normal.isEmpty()) {
normal.set(inner.getLeft(), inner.getTop(),inner.getRight(), inner.getBottom());
}
inner.layout(inner.getLeft(), inner.getTop() - deltaY / 2,inner.getRight(), inner.getBottom() - deltaY / 2);
}
isCount = true;
break;
default:
break;
}
}
public void animation() {
TranslateAnimation ta = new TranslateAnimation(0, 0, inner.getTop(),normal.top);
ta.setDuration(200);
inner.startAnimation(ta);
inner.layout(normal.left, normal.top, normal.right, normal.bottom);
normal.setEmpty();
}
// return left >= right || top >= bottom;
public boolean isNeedAnimation() {
return !normal.isEmpty();
}
public boolean isNeedMove() {
int offset = inner.getMeasuredHeight() - getHeight();
int scrollY = getScrollY();
if (scrollY == 0 || scrollY == offset) {
return true;
}
return false;
}
}
——————————————————————————方式二——————————————————————————
CustomScrollView
package com.example.scrollviewdemo;
import android.content.Context;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.TranslateAnimation;
import android.widget.ScrollView;
public class CustomScrollView extends ScrollView {
// y方向上当前触摸点的前一次记录位置
private int previousY = 0;
// y方向上的触摸点的起始记录位置
private int startY = 0;
// y方向上的触摸点当前记录位置
private int currentY = 0;
// y方向上两次移动间移动的相对距离
private int deltaY = 0;
// 第一个子视图
private View childView;
// 用于记录childView的初始位置
private Rect topRect = new Rect();
public CustomScrollView(Context context) {
super(context);
;
}
public CustomScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
;
}
public CustomScrollView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
;
}
@Override
protected void onFinishInflate() {
if (getChildCount() > 0) {
childView = getChildAt(0);
}
}
@Override
public boolean dispatchTouchEvent(MotionEvent event) {
if (null == childView) {
return super.dispatchTouchEvent(event);
}
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
startY = (int) event.getY();
previousY = startY;
break;
case MotionEvent.ACTION_MOVE:
currentY = (int) event.getY();
deltaY = previousY - currentY;
previousY = currentY;
if (0 == getScrollY()
|| childView.getMeasuredHeight() - getHeight() <= getScrollY()) {
// 记录childView的初始位置
if (topRect.isEmpty()) {
topRect.set(childView.getLeft(), childView.getTop(),
childView.getRight(), childView.getBottom());
}
// 更新childView的位置
childView.layout(childView.getLeft(), childView.getTop()
- deltaY / 3, childView.getRight(),
childView.getBottom() - deltaY / 3);
}
break;
case MotionEvent.ACTION_UP:
if (!topRect.isEmpty()) {
upDownMoveAnimation();
// 子控件回到初始位置
childView.layout(topRect.left, topRect.top, topRect.right,
topRect.bottom);
}
startY = 0;
currentY = 0;
topRect.setEmpty();
break;
default:
break;
}
return super.dispatchTouchEvent(event);
}
// 初始化上下回弹的动画效果
private void upDownMoveAnimation() {
TranslateAnimation animation = new TranslateAnimation(0.0f, 0.0f,
childView.getTop(), topRect.top);
animation.setDuration(200);
animation.setInterpolator(new AccelerateInterpolator());
childView.setAnimation(animation);
}
}
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