Android中的动画具体解释系列【2】——飞舞的蝴蝶

这一篇来使用逐帧动画和补间动画来实现一个小样例，首先我们来看看Android中的补间动画。

Android中使用Animation代表抽象的动画类，该类包含以下几个子类：

AlphaAnimation:透明改变动画。

ScaleAnimation:大小缩放动画。

TranslateAnimation:位移变化动画。

RotateAnimation:旋转动画。

我们以下使用位移动画和逐帧动画来实现这个小样例。先看看执行效果：

蝴蝶挥动翅膀的逐帧动画文件：

<?xml version="1.0" encoding="utf-8"?>
<!-- 定义动画循环播放 -->
<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
	android:oneshot="false">
	<item android:drawable="@drawable/butterfly_f01" android:duration="120" />
	<item android:drawable="@drawable/butterfly_f02" android:duration="120" />
	<item android:drawable="@drawable/butterfly_f03" android:duration="120" />
	<item android:drawable="@drawable/butterfly_f04" android:duration="120" />
	<item android:drawable="@drawable/butterfly_f05" android:duration="120" />
	<item android:drawable="@drawable/butterfly_f06" android:duration="120" />																
</animation-list>

<?xml version="1.0" encoding="utf-8"?
>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:orientation="vertical"
	android:layout_width="fill_parent"
	android:layout_height="fill_parent"
	android:background="@drawable/background"
	>
<ImageView
	android:id="@+id/butterfly"
	android:layout_width="wrap_content" 
	android:layout_height="wrap_content" 
	android:background="@anim/butteryfly"
	/>
</LinearLayout>

package com.example.butteryfly;

import java.util.Timer;
import java.util.TimerTask;

import android.app.Activity;
import android.graphics.drawable.AnimationDrawable;
import android.os.Bundle;
import android.os.Handler;
import android.view.Display;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.TranslateAnimation;
import android.widget.ImageView;

public class MainActivity extends Activity {
	
	private float curX = 0;
	private float curY = 30;
	
	private float nextX = 0;
	private float nextY = 0;
	
	private int windowW = 0;
	private int windowH = 0;
	
	private ImageView imageView;
	
	Handler handler = new Handler(){
		public void handleMessage(android.os.Message msg) {
			if(msg.what == 0x123){
				if(nextX > windowW || nextY > windowH){
					curX = nextX = 0;
				}else{
					nextX += 8;
				}
				
				nextY = curY + (float) (Math.random() * 20 - 10);
				TranslateAnimation anim = new TranslateAnimation(curX, nextX, curY, nextY);
				curX = nextX;
				curY = nextY;
				anim.setDuration(200);
				imageView.startAnimation(anim);
			}
		};
	};
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		imageView = (ImageView) findViewById(R.id.butterfly);
		
		Display display = getWindowManager().getDefaultDisplay(); 
		windowW = display.getWidth();
		windowH = display.getHeight();
		
		final AnimationDrawable butterfly = (AnimationDrawable) imageView.getBackground();
		imageView.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View arg0) {
				butterfly.start();
				new Timer().schedule(new TimerTask() {
					
					@Override
					public void run() {
						handler.sendEmptyMessage(0x123);
					}
				}, 0, 200);
			}
		});
	}
}