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最新推荐文章于 2024-05-16 23:37:49 发布

原创最新推荐文章于 2024-05-16 23:37:49 发布 · 1.1k 阅读

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本文介绍了一种实现带有上下反弹效果的ScrollView方案，并解决了ScrollView与ListView嵌套显示的问题。通过自定义BounceScrollView类，实现了手指滑动时的跟随效果及松手后的回弹动画，同时提供了跳转到新页面的功能。

源码：http://download.youkuaiyun.com/detail/lm_zp/9534749

activity_main.xml

<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"
  >

    <com.example.zhy_bouncescrollview02.BounceScrollView
        android:background="@drawable/shakehideimg_man"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/id_scrollView" >

        <com.example.zhy_bouncescrollview02.MyListView
            android:background="#fff"
            android:id="@+id/id_listView"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" >
        </com.example.zhy_bouncescrollview02.MyListView>
    </com.example.zhy_bouncescrollview02.BounceScrollView>

</RelativeLayout>

second.xml

<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"
   
  >

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:text="新页面" />

</RelativeLayout>

res/anim/fade_in.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" >


    <alpha
        android:duration="200"
        android:fromAlpha="0.0"
        android:toAlpha="1.0" >
    </alpha>


    <scale
        android:duration="200"
        android:fromXScale="0"
        android:fromYScale="0"
        android:pivotX="50%p"
        android:pivotY="50%p"
        android:toXScale="1"
        android:toYScale="1" />




</set>

res/anim/fade_out.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" >

    <alpha
        android:duration="200"
        android:fromAlpha="1.0"
        android:toAlpha="0.0" >
    </alpha>

    <scale
        android:duration="200"
        android:fromXScale="1"
        android:fromYScale="1"
        android:pivotX="50%p"
        android:pivotY="50%p"
        android:toXScale="0"
        android:toYScale="0" />

</set>

MainActivity.java

package com.example.zhy_bouncescrollview02;

import java.util.ArrayList;
import java.util.Arrays;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

import com.example.zhy_bouncescrollview02.BounceScrollView.Callback;

public class MainActivity extends Activity
{

	private ListView mListView;
	private BounceScrollView mScrollView;

	@Override
	protected void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		mScrollView = (BounceScrollView) findViewById(R.id.id_scrollView);
		mScrollView.setCallBack(new Callback()
		{

			@Override
			public void callback()
			{
				Toast.makeText(MainActivity.this, "跳转新页面", 0)
						.show();
				Intent intent = new Intent(MainActivity.this,
						SecondActivity.class);
				startActivity(intent);
				overridePendingTransition(R.anim.fade_in, R.anim.fade_out);
			}
		});
		mListView = (ListView) findViewById(R.id.id_listView);
		mListView.setAdapter(new ArrayAdapter<String>(this,
				android.R.layout.simple_list_item_1, new ArrayList<String>(
						Arrays.asList("Hello", "World", "Welcome", "Java",
								"Android", "Lucene", "C++", "C#", "HTML",
								"Welcome", "Java", "Android", "Lucene", "C++",
								"C#", "HTML"))));
	}

}

MyListView.java

package com.example.zhy_bouncescrollview02;


import android.content.Context;
import android.util.AttributeSet;
import android.widget.ListView;

/**
 * 解决ScrollView与ListView的嵌套问题
 * @author zhy
 * 
 */
public class MyListView extends ListView
{

	public MyListView(Context context, AttributeSet attrs)
	{
		super(context, attrs);
	}

	public MyListView(Context context, AttributeSet attrs, int defStyle)
	{
		super(context, attrs, defStyle);
	}

	public MyListView(Context context)
	{
		super(context);
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
	{

		/**
		 * 解决ScrollView与ListView的嵌套问题
		 */
		int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,
				MeasureSpec.AT_MOST);

		super.onMeasure(widthMeasureSpec, expandSpec);
	}

}

SecondActivity.java

package com.example.zhy_bouncescrollview02;

import android.app.Activity;
import android.os.Bundle;

public class SecondActivity extends Activity
{
	@Override
	protected void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.second);
		
	}
}

BounceScrollView.java

package com.example.zhy_bouncescrollview02;

import android.content.Context;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.TranslateAnimation;
import android.widget.ScrollView;

/**
 * 支持上下反弹效果的ScrollView
 * 
 * @author zhy
 * 
 */
public class BounceScrollView extends ScrollView
{

	private boolean isCalled ; 
	
	private Callback mCallback;

	/**
	 * 包含的View
	 */
	private View mView;
	/**
	 * 存储正常时的位置
	 */
	private Rect mRect = new Rect();

	/**
	 * y坐标
	 */
	private int y;

	private boolean isFirst = true;

	public BounceScrollView(Context context, AttributeSet attrs)
	{
		super(context, attrs);
	}

	/***
	 * 根据 XML 生成视图工作完成.该函数在生成视图的最后调用，在所有子视图添加完之后. 即使子类覆盖了 onFinishInflate
	 * 方法，也应该调用父类的方法，使该方法得以执行.
	 */
	@Override
	protected void onFinishInflate()
	{
		if (getChildCount() > 0)
			mView = getChildAt(0);
		super.onFinishInflate();
	}

	@Override
	public boolean onTouchEvent(MotionEvent ev)
	{
		if (mView != null)
		{
			commonOnTouch(ev);
		}

		return super.onTouchEvent(ev);
	}

	private void commonOnTouch(MotionEvent ev)
	{
		int action = ev.getAction();
		int cy = (int) ev.getY();
		switch (action)
		{
		case MotionEvent.ACTION_DOWN:
			break;
		/**
		 * 跟随手指移动
		 */
		case MotionEvent.ACTION_MOVE:

			int dy = cy - y;
			if (isFirst)
			{
				dy = 0;
				isFirst = false;
			}
			y = cy;

			if (isNeedMove())
			{
				if (mRect.isEmpty())
				{
					/**
					 * 记录移动前的位置
					 */
					mRect.set(mView.getLeft(), mView.getTop(),
							mView.getRight(), mView.getBottom());
				}

				mView.layout(mView.getLeft(), mView.getTop() + 2 * dy / 3,
						mView.getRight(), mView.getBottom() + 2 * dy / 3);

				if (shouldCallBack(dy))
				{
					if (mCallback != null)
					{
						if(!isCalled)
						{
							isCalled = true ; 
							resetPosition();
							mCallback.callback();
							
							
						}
					}
				}
			}

			break;
		/**
		 * 反弹回去
		 */
		case MotionEvent.ACTION_UP:
			if (!mRect.isEmpty())
			{
				resetPosition();
			}
			break;

		}
	}

	/**
	 * 当从上往下，移动距离达到一半时，回调接口
	 * 
	 * @return
	 */
	private boolean shouldCallBack(int dy)
	{

		if (dy > 0 && mView.getTop() > getHeight() / 2)
			return true;
		return false;
	}

	private void resetPosition()
	{
		Animation animation = new TranslateAnimation(0, 0, mView.getTop(),
				mRect.top);
		animation.setDuration(200);
		animation.setFillAfter(true);
		mView.startAnimation(animation);
		mView.layout(mRect.left, mRect.top, mRect.right, mRect.bottom);
		mRect.setEmpty();
		isFirst = true;
		isCalled = false ; 
	}

	/***
	 * 是否需要移动布局 inner.getMeasuredHeight():获取的是控件的总高度
	 * 
	 * getHeight()：获取的是屏幕的高度
	 * 
	 * @return
	 */
	public boolean isNeedMove()
	{
		int offset = mView.getMeasuredHeight() - getHeight();
		int scrollY = getScrollY();
		// 0是顶部，后面那个是底部
		if (scrollY == 0 || scrollY == offset)
		{
			return true;
		}
		return false;
	}

	public void setCallBack(Callback callback)
	{
		mCallback = callback;
	}

	interface Callback
	{
		void callback();
	}

}