Android 之AnimationDrawable

AnimationDrawable是Android实现动画的一种简单的形式。如果需要简单的动画，例如屏幕锁。这里用一个Demo来简单讲解下。

 

首先最基本的，我们可以参见DOC上的说明，它的资料最正宗！

Class Overview

An object used to create frame-by-frame animations, defined by a series of Drawable objects, which can be used as a View object's background.

The simplest way to create a frame-by-frame animation is to define the animation in an XML file, placed in the res/drawable/ folder, and set it as the background to a View object. Then, call run() to start the animation.

An AnimationDrawable defined in XML consists of a single <animation-list> element, and a series of nested <item> tags. Each item defines a frame of the animation. See the example below.

spin_animation.xml file in res/drawable/ folder:

<!-- Animation frames are wheel0.png -- wheel5.png files inside the

 res/drawable/ folder -->


 
<animation-list
 
android:id
=
"selected"
 
android:oneshot
=
"false"
>


    
<item
 
android:drawable
=
"@drawable/wheel0"
 
android:duration
=
"50"
 
/>


    
<item
 
android:drawable
=
"@drawable/wheel1"
 
android:duration
=
"50"
 
/>


    
<item
 
android:drawable
=
"@drawable/wheel2"
 
android:duration
=
"50"
 
/>


    
<item
 
android:drawable
=
"@drawable/wheel3"
 
android:duration
=
"50"
 
/>


    
<item
 
android:drawable
=
"@drawable/wheel4"
 
android:duration
=
"50"
 
/>


    
<item
 
android:drawable
=
"@drawable/wheel5"
 
android:duration
=
"50"
 
/>


 
</animation-list>

Here is the code to load and play this animation.

 
// Load the ImageView that will host the animation and


 
// set its background to our AnimationDrawable XML resource.


 
ImageView
 img 
=
 
(
ImageView
)
findViewById
(
R
.
id
.
spinning_wheel_image
);


 img
.
setBackgroundResource
(
R
.
drawable
.
spin_animation
);




 
// Get the background, which has been compiled to an AnimationDrawable object.


 
AnimationDrawable
 frameAnimation 
=
 
(
AnimationDrawable
)
 img
.
getBackground
();




 
// Start the animation (looped playback by default).


 frameAnimation
.
start
()




以上的资料大家也可以在DOC中看的很明白。



一：新建一个工程AnimationDrawableDemo。

二：在res/drawable下面放入我们需要演示的图片。

lock_anim_00.png

lock_anim_02.png

lock_anim_04.png

lock_anim_06.png

lock_anim_08.png

lock_anim_10.png

lock_anim_12.png

lock_anim_14.png





新建一个Animation资源文件。文件如下：

<?xml version="1.0" encoding="utf-8"?>

<animation-list
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:oneshot="false">
    <item android:drawable="@drawable/lock_anim_00" android:duration="400" />
    <item android:drawable="@drawable/lock_anim_02" android:duration="400" />
    <item android:drawable="@drawable/lock_anim_04" android:duration="400" />
    <item android:drawable="@drawable/lock_anim_06" android:duration="400" />
    <item android:drawable="@drawable/lock_anim_08" android:duration="400" />
    <item android:drawable="@drawable/lock_anim_10" android:duration="400" />
    <item android:drawable="@drawable/lock_anim_12" android:duration="400" />
    <item android:drawable="@drawable/lock_anim_14" android:duration="400" />
</animation-list>

 



三：在main.xml文件中导入一个ImageView控件。函数代码如下：

package com.rocky.studio.ch02.ex2;

import android.app.Activity;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.graphics.drawable.AnimationDrawable;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class AnimationDrawableDemo extends Activity {
	
	private Button m_RunButton;
	private Button m_StopButton;
	private ImageView imgView;
	private AnimationDrawable mAnimation;
	private static final long START_DELAY = 1000;
	
	
	private Handler mHandler = new Handler();
    private Runnable mRunnable = new Runnable() {
        public void run() {
            startAnimation(mAnimation);
        }
    };
	
	
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
                
        m_RunButton=(Button)this.findViewById(R.id.Button01);
        m_StopButton=(Button)this.findViewById(R.id.Button02);
        m_RunButton.setOnClickListener( m_BtnRunClickListener);
        m_StopButton.setOnClickListener(m_BtnStopClickListener);
       
        imgView=(ImageView)this.findViewById(R.id.ImageView01);
        
        imgView.setBackgroundResource(R.drawable.lock_anim);
        mAnimation = (AnimationDrawable) imgView.getBackground();
    }
    @Override
	protected void onPause() {
		// TODO Auto-generated method stub
		super.onPause();
		//stopAnimation(mAnimation);
	}

	@Override
	protected void onResume() {
		// TODO Auto-generated method stub
		super.onResume();
		//mHandler.postDelayed(mRunnable, START_DELAY);
	}
	private View.OnClickListener m_BtnRunClickListener=new View.OnClickListener()
    {	
		public void onClick(View arg0) {
			// TODO Auto-generated method stub
			startAnimation(mAnimation);
		}    	
    };
    private View.OnClickListener m_BtnStopClickListener=new View.OnClickListener()
    {
		public void onClick(View arg0) {
			// TODO Auto-generated method stub
			stopAnimation(mAnimation);
		}
		
    };
    protected void startAnimation(final AnimationDrawable animation) {
        if (animation != null && !animation.isRunning()) {
            animation.run();
        }
    }
   
    protected void stopAnimation(final AnimationDrawable animation) {
        if (animation != null && animation.isRunning()) animation.stop();
    }
    
}
 





四：如果需要一打开就动画显示：//mHandler.postDelayed(mRunnable, START_DELAY);

这句话的意思是开启一个线程，开始执行操作。



五：这样就基本完成了操作。最好还是些个Demo来测试练练手。