今天实现了类似淘宝上划操作显示详情页的demo

原理是自定义一个控件，控件中包含两个scrollview控件，scrollview中可以放入自己需要的东西，我是在第二个控件中加入的webview自定义控件源码如下：package cn.doolii.view;import java.util.Timer;import java.util.TimerTask;import android.content.Context;import android.os.Handler;import android.os.Message;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.VelocityTracker;import android.view.View;import android.widget.RelativeLayout;import android.widget.ScrollView;public class ScrollViewContainer extends RelativeLayout { /** * 自动上滑 */ public static final int AUTO_UP = 0; /** * 自动下滑 */ public static final int AUTO_DOWN = 1; /** * 动画完成 */ public static final int DONE = 2; /** * 动画速度 */ public static final float SPEED = 6.5f; private boolean isMeasured = false; /** * 用于计算手滑动的速度 */ private VelocityTracker vt; private int mViewHeight; private int mViewWidth; private View topView; private View bottomView; private boolean canPullDown; private boolean canPullUp; private int state = DONE; /** * 记录当前展示的是哪个view，0是topView，1是bottomView */ private int mCurrentViewIndex = 0; /** * 手滑动距离，这个是控制布局的主要变量 */ private float mMoveLen; private MyTimer mTimer; private float mLastY; /** * 用于控制是否变动布局的另一个条件，mEvents==0时布局可以拖拽了，mEvents==-1时可以舍弃将要到来的第一个move事件， * 这点是去除多点拖动剧变的关键 */ private int mEvents; private Handler handler = new Handler() { @Override public void handleMessage(Message msg) { if (mMoveLen != 0) { if (state == AUTO_UP) { mMoveLen -= SPEED; if (mMoveLen <= -mViewHeight) { mMoveLen = -mViewHeight; state = DONE; mCurrentViewIndex = 1; } } else if (state == AUTO_DOWN) { mMoveLen += SPEED; if (mMoveLen >= 0) { mMoveLen = 0; state = DONE; mCurrentViewIndex = 0; } } else { mTimer.cancel(); } } requestLayout(); } }; public ScrollViewContainer(Context context) { super(context); init(); } public ScrollViewContainer(Context context, AttributeSet attrs) { super(context, attrs); init(); } public ScrollViewContainer(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(); } private void init() { mTimer = new MyTimer(handler); } @Override public boolean dispatchTouchEvent(MotionEvent ev) { switch (ev.getActionMasked()) { case MotionEvent.ACTION_DOWN: if (vt == null) vt = VelocityTracker.obtain(); else vt.clear(); mLastY = ev.getY(); vt.addMovement(ev); mEvents = 0; break; case MotionEvent.ACTION_POINTER_DOWN: case MotionEvent.ACTION_POINTER_UP: // 多一只手指按下或抬起时舍弃将要到来的第一个事件move，防止多点拖拽的bug mEvents = -1; break; case MotionEvent.ACTION_MOVE: vt.addMovement(ev); if (canPullUp && mCurrentViewIndex == 0 && mEvents == 0) { mMoveLen += (ev.getY() - mLastY); // 防止上下越界 if (mMoveLen > 0) { mMoveLen = 0; mCurrentViewIndex = 0; } else if (mMoveLen < -mViewHeight) { mMoveLen = -mViewHeight; mCurrentViewIndex = 1; } if (mMoveLen < -8) { // 防止事件冲突 ev.setAction(MotionEvent.ACTION_CANCEL); } } else if (canPullDown && mCurrentViewIndex == 1 && mEvents == 0) { mMoveLen += (ev.getY() - mLastY); // 防止上下越界 if (mMoveLen < -mViewHeight) { mMoveLen = -mViewHeight; mCurrentViewIndex = 1; } else if (mMoveLen > 0) { mMoveLen = 0; mCurrentViewIndex = 0; } if (mMoveLen > 8 - mViewHeight) { // 防止事件冲突 ev.setAction(MotionEvent.ACTION_CANCEL); } } else mEvents++; mLastY = ev.getY(); requestLayout(); break; case MotionEvent.ACTION_UP: mLastY = ev.getY(); vt.addMovement(ev); vt.computeCurrentVelocity(700); // 获取Y方向的速度 float mYV = vt.getYVelocity(); if (mMoveLen == 0 || mMoveLen == -mViewHeight) break; if (Math.abs(mYV) < 500) { // 速度小于一定值的时候当作静止释放，这时候两个View往哪移动取决于滑动的距离 if (mMoveLen <= -mViewHeight / 2) { state = AUTO_UP; } else if (mMoveLen > -mViewHeight / 2) { state = AUTO_DOWN; } } else { // 抬起手指时速度方向决定两个View往哪移动 if (mYV < 0) state = AUTO_UP; else state = AUTO_DOWN; } mTimer.schedule(2); try { //此处重点 必须加上 vt=null; 否则会报java.lang.IllegalStateException: Already in the pool! vt.recycle(); vt=null; } catch (Exception e) { e.printStackTrace(); } break; } super.dispatchTouchEvent(ev); return true; } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { topView.layout(0, (int) mMoveLen, mViewWidth, topView.getMeasuredHeight() + (int) mMoveLen); bottomView.layout(0, topView.getMeasuredHeight() + (int) mMoveLen, mViewWidth, topView.getMeasuredHeight() + (int) mMoveLen + bottomView.getMeasuredHeight()); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (!isMeasured) { isMeasured = true; mViewHeight = getMeasuredHeight(); mViewWidth = getMeasuredWidth(); topView = getChildAt(0); bottomView = getChildAt(1); bottomView.setOnTouchListener(bottomViewTouchListener); topView.setOnTouchListener(topViewTouchListener); } } private OnTouchListener topViewTouchListener = new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { ScrollView sv = (ScrollView) v; if (sv.getScrollY() == (sv.getChildAt(0).getMeasuredHeight() - sv .getMeasuredHeight()) && mCurrentViewIndex == 0) canPullUp = true; else canPullUp = false; return false; } }; private OnTouchListener bottomViewTouchListener = new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { ScrollView sv = (ScrollView) v; if (sv.getScrollY() == 0 && mCurrentViewIndex == 1) canPullDown = true; else canPullDown = false; return false; } }; class MyTimer { private Handler handler; private Timer timer; private MyTask mTask; public MyTimer(Handler handler) { this.handler = handler; timer = new Timer(); } public void schedule(long period) { if (mTask != null) { mTask.cancel(); mTask = null; } mTask = new MyTask(handler); timer.schedule(mTask, 0, period); } public void cancel() { if (mTask != null) { mTask.cancel(); mTask = null; } } class MyTask extends TimerTask { private Handler handler; public MyTask(Handler handler) { this.handler = handler; } @Override public void run() { handler.obtainMessage().sendToTarget(); } } }}MainActivity代码如下：package com.example.lzq.scrollview;import android.app.Activity;import android.os.Bundle;import android.support.design.widget.FloatingActionButton;import android.support.design.widget.Snackbar;import android.support.v7.app.AppCompatActivity;import android.support.v7.widget.Toolbar;import android.view.View;import android.view.Menu;import android.view.MenuItem;public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.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(); //noinspection SimplifiableIfStatement if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); }}activity_main如下：<?xml version="1.0" encoding="utf-8"?>