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

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{@Overridepublic void onAnimationEnd(Animation arg0) {// TODO Auto-generated method stub}@Overridepublic void onAnimationRepeat(Animation arg0) {// TODO Auto-generated method stub}@Overridepublic 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：

public class MainActivity extends Activity {private Button button;private Button button2;private ImageView imageView;private ViewGroup viewGroup;@Overrideprotected 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{@Overridepublic void onClick(View v) {// TODO Auto-generated method stubswitch (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{@Overridepublic void onAnimationEnd(Animation arg0) {// TODO Auto-generated method stubviewGroup.removeView(imageView);Log.d("BruceZhang", "Animation End!");}@Overridepublic void onAnimationRepeat(Animation arg0) {// TODO Auto-generated method stubLog.d("BruceZhang", "Animation Repeat!");}@Overridepublic void onAnimationStart(Animation arg0) {// TODO Auto-generated method stubLog.d("BruceZhang", "Animation Start!");}}@Overridepublic 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：

<AbsoluteLayout xmlns:android="/apk/res/android"xmlns:tools="/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity" android:id="@+id/viewGroup"><Buttonandroid: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" /><Buttonandroid: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" /><ImageViewandroid: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>