ListView阻尼效果

本文主要是介绍ListView阻尼效果，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

效果图省略。。。

activity_main.xml（只有一个自定义ListView）

<RelativeLayout 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"tools:context="com.example.dampingdemo.MainActivity" ><com.example.dampingdemo.DampingListView1android:id="@+id/listView"android:layout_width="fill_parent"android:layout_height="fill_parent" ></com.example.dampingdemo.DampingListView1></RelativeLayout>

MainActivity(ArrayListAdapter 为了简化代码)

package com.example.dampingdemo;import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;public class MainActivity extends Activity {private DampingListView1 dampingListView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);dampingListView = (DampingListView1) findViewById(R.id.listView);//dataString[] data = {"A","B","C","A","B","C","A","B","C","A","B","C","A","B","C","A","B","C","A","B","C","A","B","C"};  //获取适配器  ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,data );  //设置适配器  dampingListView.setAdapter(adapter);  }
}

DampingListView1（第一种方法）

package com.example.dampingdemo;import android.content.Context;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.ExpandableListView;
import android.widget.ListView;
/***   1. 在View中增加了overSrollBy方法,用于记录x, y 轴上滚动2. 在AbsListView的onTouchEvent中判断是否到达边界(顶部 或 底部) ,然后调用view.overScrollBy ,传入 mScrollY等参数3. overScrollBy 最终赋值给View的mScrollX, mScrollY 两个变量4. 在AbsListView中调用完overScrollBy之后,调用invalidate重绘**/
public class DampingListView1 extends ListView {private static final int MAX_Y_OVERSCROLL_DISTANCE = 200;private Context mContext;private int mMaxYOverscrollDistance;public DampingListView1(Context context) {super(context);mContext = context;initBounceListView();}public DampingListView1(Context context, AttributeSet attrs) {super(context, attrs);mContext = context;initBounceListView();}public DampingListView1(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);mContext = context;initBounceListView();}private void initBounceListView() {final DisplayMetrics metrics = mContext.getResources().getDisplayMetrics();final float density = metrics.density;mMaxYOverscrollDistance = (int) (density * MAX_Y_OVERSCROLL_DISTANCE);}@Overrideprotected boolean overScrollBy(int deltaX, int deltaY, int scrollX,int scrollY, int scrollRangeX, int scrollRangeY,int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent) {return super.overScrollBy(deltaX, deltaY, scrollX, scrollY,scrollRangeX, scrollRangeY, maxOverScrollX,mMaxYOverscrollDistance, isTouchEvent);}}

+++++++++++++++++++++++++++或者第二种方法+++++++++++++++++++++++++++++++++++++++

DampingListView

package com.example.dampingdemo;import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.ExpandableListView;
import android.widget.ListView;public class DampingListView extends ListView implements Runnable {// 手指点位置的Y坐标private float mLastDownY = 0f;// 移动距离private int mDistance = 0;private int mStep = 0;// 是否移动过private boolean mPositive = false;/*** 构造器*/public DampingListView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);}public DampingListView(Context context, AttributeSet attrs) {super(context, attrs);}public DampingListView(Context context) {super(context);}/*** TouchEvent事件*/@Overridepublic boolean onTouchEvent(MotionEvent event) {switch (event.getAction()) {case MotionEvent.ACTION_DOWN:// 系列事件，手指第一次按下时触发if (mLastDownY == 0f && mDistance == 0) {mLastDownY = event.getY();return true;}break;case MotionEvent.ACTION_CANCEL:break;case MotionEvent.ACTION_UP:// 手指离开之后触发if (mDistance != 0) {mStep = 1;mPositive = (mDistance >= 0);// 即可把你的Runnable对象增加到UI线程中运行。this.post(this);return true;}// 重新赋值mLastDownY = 0f;mDistance = 0;break;case MotionEvent.ACTION_MOVE: // 手指按下之后滑动触发if (mLastDownY != 0f) {mDistance = (int) (mLastDownY - event.getY());if ((mDistance < 0 && getFirstVisiblePosition() == 0 && getChildAt(0).getTop() == 0)|| (mDistance > 0 && getLastVisiblePosition() == getCount() - 1)) {// 第一个位置并且是想下拉，就滑动或者最后一个位置向上拉// 这个判断的作用是在非顶端的部分不会有此滚动mDistance /= 3; // 这里是为了减少滚动的距离scrollTo(0, mDistance); // 滚动return true;}}// 置为0，有自动滑动的效果mDistance = 0;break;}return super.onTouchEvent(event);}public void run() {mDistance += mDistance > 0 ? -mStep : mStep;scrollTo(0, mDistance);// 下拉mPositive是false,上拉是trueif ((mPositive && mDistance <= 0) || (!mPositive && mDistance >= 0)) {scrollTo(0, 0);mDistance = 0;mLastDownY = 0f;return;}mStep += 1;this.post(this);}
}

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