android中的动画之变化动画事例3

 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     <LinearLayout
15         android:gravity="center"
16         android:layout_width="fill_parent"
17         android:layout_height="fill_parent"
18         android:orientation="vertical" >
19 
20         <ImageView
21             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     @Override
25     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--3s
29         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 }