Android动画——布局联动

业务情景：界面的某一部分布局在可控的情况下实现伸缩效果，同时与此布局相关联的布局随着伸缩的进行而运动。

知识准备：

1）一个添加伸缩动画的控件的大小不随伸缩动画的进行而改变，改变的只是显示效果，其他控件的位置不会随该控件的显示效果的改变而改变，因为它的大小都没变，该规则同样适用于布局（如：RelativeLayout）

2）一个添加平移动画的控件的位置不随平移动画的进行而改变，改变的只是显示效果，其他控件的位置不会随该控件的显示效果的改变而改变，因为它的位置都没变，该规则同样适用于布局（如：RelativeLayout）

实现方案：

1）当上面的控件开始收缩动画时，下面的控件开始向上移动的动画，直到顶部与上面的控件的顶部对齐。

2）当上面的控件开始伸展动画时，下面的控件开始向下移动的动画，直到顶部与上面的控件的底部对齐。

代码：

MainActivity.java

package com.example.testanoication;

import com.example.testanoication.zoom.VerticalZoom;

import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.app.Activity;

public class MainActivity extends Activity {

public boolean isShow = true;

private RelativeLayout layout = null;
private ImageView button = null;

private VerticalZoom zoom = null;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

layout = (RelativeLayout)findViewById(R.id.relativelayout);
button = (ImageView)findViewById(R.id.button);

zoom = new VerticalZoom(layout, button);
}

public void onButton(View v)
{
if(isShow)
{
isShow = false;

zoom.shrinkUpView();
}
else
{
isShow = true;

zoom.extendUpView();
}
}

}

Vertical.java

/**
*@PROJECT:TestAnoication
*@PACKAGE：com.example.testanoication.zoom
*@FILE:Vertical.java
*@TIME:2013-9-14 上午8:44:10
*@AUTHOR:
*@TODO:
*/
package com.example.testanoication.zoom;

import android.annotation.SuppressLint;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.ScaleAnimation;
import android.view.animation.TranslateAnimation;
import android.view.animation.Animation.AnimationListener;
import android.widget.RelativeLayout;
import android.widget.RelativeLayout.LayoutParams;

@SuppressLint("NewApi")
public class VerticalZoom {

private View _upview = null;
private View _downview = null;

private boolean _isupviewshow = true;
private int _upviewheight = 0;

public VerticalZoom(View upview, View downview)
{
_upview = upview;
_downview = downview;
}

/**
* 收缩上视图
* */
public void shrinkUpView()
{
initUpViewHeight();

if(_isupviewshow)
{
_isupviewshow = false;

ScaleAnimation sanimation = new ScaleAnimation(1.0f, 1.0f, 1.0f, 0.0f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.0f);
sanimation.setDuration(500);
sanimation.setFillAfter(true);

TranslateAnimation tanimation = new TranslateAnimation(_downview.getX(),  _downview.getX(), 0.0f, -_upviewheight);
tanimation.setDuration(500);
tanimation.setFillAfter(true);
tanimation.setAnimationListener(new DownViewListener());

_upview.startAnimation(sanimation);
_downview.startAnimation(tanimation);
}
}

/**
* 展开上视图
* */
public void extendUpView()
{
initUpViewHeight();

if(!_isupviewshow)
{
_isupviewshow = true;

ScaleAnimation sanimation = new ScaleAnimation(1.0f, 1.0f, 0.0f, 1.0f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.0f);
sanimation.setDuration(500);
sanimation.setFillAfter(true);

TranslateAnimation tanimation = new TranslateAnimation(_downview.getX(), _downview.getX(), 0.0f, _upviewheight);
tanimation.setDuration(500);
tanimation.setFillAfter(true);
tanimation.setAnimationListener(new DownViewListener());

_upview.startAnimation(sanimation);
_downview.startAnimation(tanimation);
}
}

private void initUpViewHeight()
{
if(_upviewheight == 0)
{
_upviewheight = _upview.getHeight();
}
}

private class DownViewListener implements AnimationListener
{
public void onAnimationEnd(Animation animation) {
LayoutParams params = new LayoutParams(LayoutParams.MATCH_PARENT,_downview.getHeight());
if(_isupviewshow)
{
params.addRule(RelativeLayout.BELOW, _upview.getId());
}
else
{
params.addRule(RelativeLayout.ALIGN_TOP, _upview.getId());
}
_downview.setLayoutParams(params);
_upview.clearAnimation();
_downview.clearAnimation();
}

public void onAnimationRepeat(Animation animation) {
}

public void onAnimationStart(Animation animation) {
}
}

}

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" >

<RelativeLayout
android:id="@+id/relativelayout"
android:layout_width="match_parent"
android:layout_height="100dp"
android:layout_alignParentTop="true">

<ImageView
android:id="@+id/image"
android:layout_width="match_parent"
android:layout_height="60dp"
android:layout_alignParentTop="true"
android:src="@drawable/kedugen"/>

<TextView
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_below="@id/image"
android:text="@string/hello_world"
android:textSize="16sp"
android:textColor="#3d3e40"
android:gravity="center"/>
</RelativeLayout>

<ImageView
android:id="@+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/relativelayout"
android:src="@drawable/kedugen"
android:onClick="onButton" />
</RelativeLayout>