1  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 2     xmlns:tools="http://schemas.android.com/tools" 3     android:layout_width="match_parent" 4     android:layout_height="match_parent" 5     android:orientation="vertical" 6     tools:context="com.example.Tween_Animation.Alpha_MainActivity" > 7  8     <Button 9         android:id="@+id/button_scale"10         android:layout_width="fill_parent"11         android:layout_height="wrap_content"12         android:text="@string/button_stringScaleAnimation" />13 14     <LinearLayout15         android:gravity="center"16         android:layout_width="fill_parent"17         android:layout_height="fill_parent"18         android:orientation="vertical" >19 20         <ImageView21             android:id="@+id/imageview_scale"22             android:layout_width="wrap_content"23             android:layout_height="wrap_content"24             android:src="@drawable/ic_launcher" />25     </LinearLayout>26 27 </LinearLayout>

 1 package com.example.Demo3; 2  3 import com.example.androidanimation.R; 4  5 import android.app.Activity; 6 import android.os.Bundle; 7 import android.view.View; 8 import android.view.View.OnClickListener; 9 import android.view.animation.AlphaAnimation;10 import android.view.animation.Animation;11 import android.widget.Button;12 import android.widget.ImageView;13 14 public class MainActivity extends Activity implements OnClickListener{15     private Button button = null;16     private ImageView imageview = null;17     protected void onCreate(Bundle savedInstanceState) {18         super.onCreate(savedInstanceState);19         setContentView(R.layout.activity_main);20         button = (Button) findViewById(R.id.button_scale);21         imageview = (ImageView) findViewById(R.id.imageview_scale);22         button.setOnClickListener(this);23     }24     @Override25     public void onClick(View v) {26         //创建一个AlphaAnimation的对象--从0.0的透明度到1.0的透明度27         Animation animation = new AlphaAnimation(0.0f, 1.0f);28         //动画持续时间--3s29         animation.setDuration(3000);30         //动画重复次数--5次31         animation.setRepeatCount(5);32         //正序（RESTART）， 反序（REVERSE）33         animation.setRepeatMode(Animation.REVERSE);34         imageview.startAnimation(animation);35     }36     37 }