Android开发之图形图像与动画(四)AnimationListener简介

2020-04-11 12:32:11

字体：大中小

来源：转载

供稿：网友

就像Button控件有监听器一样，动画效果也有监听器，只需要实现AnimationListener就可以实现对动画效果的监听，其中需要重载三个函数，就是下面的这几个函数：

 
private class MyListenr implements AnimationListener{ 
@Override 
public void onAnimationEnd(Animation arg0) { 
// TODO Auto-generated method stub 
} 
@Override 
public void onAnimationRepeat(Animation arg0) { 
// TODO Auto-generated method stub 
} 
@Override 
public void onAnimationStart(Animation arg0) { 
// TODO Auto-generated method stub 
} 

} 

其中第一个函数的意思是在动画执行完之后需要开发者做什么，第二个函数的意思是在动画重复执行的过程中应该做什么，第三个函数的意思是当动画开始执行时有什么动作发生。

下面我实现了一个例子，点击删除按钮，图片慢慢淡去，并最终删除，当点击添加按钮时向viewGroup中添加一个imageview，实现的截图如下：

具体的实现代码如下：

复制代码代码如下:

 
public class MainActivity extends Activity { 
private Button button; 
private Button button2; 
private ImageView imageView; 
private ViewGroup viewGroup; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
setContentView(R.layout.activity_main); 
button=(Button)findViewById(R.id.button_add); 
button2=(Button)findViewById(R.id.button_delete); 
imageView=(ImageView)findViewById(R.id.imageView1); 
viewGroup=(ViewGroup)findViewById(R.id.viewGroup); 
button.setOnClickListener(new Mybutton()); 
button2.setOnClickListener(new Mybutton()); 
} 
private class Mybutton implements OnClickListener{ 
@Override 
public void onClick(View v) { 
// TODO Auto-generated method stub 
switch (v.getId()) { 
case R.id.button_add: 
Add(); 
break; 
case R.id.button_delete: 
Delete(); 
break; 
default: 
break; 
} 
} 
} 

public void Add() { 
AlphaAnimation alphaAnimation=new AlphaAnimation(0.0f, 1.0f); 
alphaAnimation.setDuration(2000); 
alphaAnimation.setStartOffset(500); 
ImageView imageViewAdd=new ImageView(MainActivity.this); 
imageViewAdd.setImageResource(R.drawable.ic_launcher); 
viewGroup.addView(imageViewAdd); 
// viewGroup.addView(imageViewAdd, new LayoutParams( 
// LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT)); 
imageViewAdd.startAnimation(alphaAnimation); 
} 
public void Delete() { 
AlphaAnimation alphaAnimation=new AlphaAnimation(1.0f, 0.0f); 
alphaAnimation.setDuration(2000); 
alphaAnimation.setStartOffset(500); 
imageView.startAnimation(alphaAnimation); 
alphaAnimation.setAnimationListener(new MyListenr()); 
} 

private class MyListenr implements AnimationListener{ 
@Override 
public void onAnimationEnd(Animation arg0) { 
// TODO Auto-generated method stub 
viewGroup.removeView(imageView); 
Log.d("BruceZhang", "Animation End!"); 
} 
@Override 
public void onAnimationRepeat(Animation arg0) { 
// TODO Auto-generated method stub 
Log.d("BruceZhang", "Animation Repeat!"); 
} 
@Override 
public void onAnimationStart(Animation arg0) { 
// TODO Auto-generated method stub 
Log.d("BruceZhang", "Animation Start!"); 
} 

} 
@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
// Inflate the menu; this adds items to the action bar if it is present. 
getMenuInflater().inflate(R.menu.activity_main, menu); 
return true; 
} 
} 

此实例的布局文件如下，注意，需要在根标签下给出viewGroup的id：

复制代码代码如下:

 
<AbsoluteLayout 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=".MainActivity" 
android:id="@+id/viewGroup" 
> 
<Button 
android:id="@+id/button_add" 
android:layout_width="match_parent" 
android:layout_height="wrap_content" 
android:layout_x="0dp" 
android:layout_y="367dp" 
android:text="添加图片" /> 
<Button 
android:id="@+id/button_delete" 
android:layout_width="match_parent" 
android:layout_height="wrap_content" 
android:layout_x="0dp" 
android:layout_y="410dp" 
android:text="删除图片" /> 
<ImageView 
android:id="@+id/imageView1" 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:layout_x="153dp" 
android:layout_y="155dp" 
android:src="@drawable/ic_launcher" /> 
</AbsoluteLayout> 