此帧动画主要用到了AnimationDrawable类和Drawable资源文件实现,在XML文件中animation-list元素为根节点,item节点定义每一帧,表示一个drawable资源的帧和帧间隔。
首先,在 Android 项目的 /res/drawable-hdpi/ 目录下加入图片资源;然后在 Android 项目的 /res/drawable/目录下新建XML文件,代码如下:
<?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/loading_01" android:duration="50" />
<item android:drawable="@drawable/loading_02" android:duration="50" />
<item android:drawable="@drawable/loading_03" android:duration="50" />
<item android:drawable="@drawable/loading_04" android:duration="50" />
<item android:drawable="@drawable/loading_05" android:duration="50" />
<item android:drawable="@drawable/loading_06" android:duration="50" />
<item android:drawable="@drawable/loading_07" android:duration="50" />
<item android:drawable="@drawable/loading_08" android:duration="50" />
<item android:drawable="@drawable/loading_09" android:duration="50" />
<item android:drawable="@drawable/loading_10" android:duration="50" />
<item android:drawable="@drawable/loading_11" android:duration="50" />
<item android:drawable="@drawable/loading_12" android:duration="50" />
</animation-list>
其中android:oneshot=”false”表示此动画会一直不停的执行下去,如果将其设置为true,则播放完一次后将停在最后一针。
布局文件中包含了一个ImageView控件和两个Button按钮,通过两个按钮来控制此动画是播放还是停止,控制代码如下:
package com.example.loadingdemo;
import android.app.Activity;
import android.graphics.drawable.AnimationDrawable;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
public class MainActivity extends Activity implements OnClickListener
{
private ImageView loading_iv;//装载动画的Imageview
private Button start_bt;//播放按钮
private Button stop_bt;//停止按钮
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
loading_iv = (ImageView) findViewById(R.id.loading_iv);
start_bt = (Button) findViewById(R.id.start_loading);
stop_bt = (Button) findViewById(R.id.stop_loading);
start_bt.setOnClickListener(this);
stop_bt.setOnClickListener(this);
}
@Override
public void onClick(View v)
{
AnimationDrawable drawable = (AnimationDrawable) loading_iv.getBackground();
switch(v.getId())
{
case R.id.start_loading:
drawable.start();
break;
case R.id.stop_loading:
drawable.stop();
break;
default:
break;
}
}
}