Android 杂谈---帧动画

Android中的动画有

• 帧动画
• 属性动画
• 补间动画

大体思路

1.需要定义存放每一帧的xml文件,放在drawable文件夹下

设置图片路径和duration,以及shot属性,false--->只播放一次,true----->播放多次

 <?xml version="1.0" encoding="utf-8"?>
 <animation-list android:oneshot="false"

   xmlns:android="http://schemas.android.com/apk/res/android">
     <item android:duration="50" android:drawable="@drawable/progressbar34" />
     <item android:duration="50" android:drawable="@drawable/progressbar33" />
     <item android:duration="50" android:drawable="@drawable/progressbar32" />
     <item android:duration="50" android:drawable="@drawable/progressbar31" />
     <item android:duration="50" android:drawable="@drawable/progressbar30" />
     <item android:duration="50" android:drawable="@drawable/progressbar29" />
     <item android:duration="50" android:drawable="@drawable/progressbar28" />
     <item android:duration="50" android:drawable="@drawable/progressbar27" />
     <item android:duration="50" android:drawable="@drawable/progressbar26" />
     <item android:duration="50" android:drawable="@drawable/progressbar25" />
     <item android:duration="50" android:drawable="@drawable/progressbar24" />
     <item android:duration="50" android:drawable="@drawable/progressbar23" />
     <item android:duration="50" android:drawable="@drawable/progressbar22" />
     <item android:duration="50" android:drawable="@drawable/progressbar21" />
     <item android:duration="50" android:drawable="@drawable/progressbar20" />
     <item android:duration="50" android:drawable="@drawable/progressbar19" />
     <item android:duration="50" android:drawable="@drawable/progressbar18" />
     <item android:duration="50" android:drawable="@drawable/progressbar17" />
     <item android:duration="50" android:drawable="@drawable/progressbar16" />
     <item android:duration="50" android:drawable="@drawable/progressbar15" />
     <item android:duration="50" android:drawable="@drawable/progressbar14" />
     <item android:duration="50" android:drawable="@drawable/progressbar13" />
     <item android:duration="50" android:drawable="@drawable/progressbar12" />
     <item android:duration="50" android:drawable="@drawable/progressbar11" />
     <item android:duration="50" android:drawable="@drawable/progressbar10" />
     <item android:duration="50" android:drawable="@drawable/progressbar9" />
     <item android:duration="50" android:drawable="@drawable/progressbar8" />
     <item android:duration="50" android:drawable="@drawable/progressbar7" />
     <item android:duration="50" android:drawable="@drawable/progressbar6" />
     <item android:duration="50" android:drawable="@drawable/progressbar5" />
     <item android:duration="50" android:drawable="@drawable/progressbar4" />
     <item android:duration="50" android:drawable="@drawable/progressbar3" />
     <item android:duration="50" android:drawable="@drawable/progressbar2" />
     <item android:duration="50" android:drawable="@drawable/progressbar1" />
 </animation-list>

progress.xml

2.指定存放该动画的容器,使用imageView来充当

 <?xml version="1.0" encoding="utf-8"?>
 <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     tools:context="com.jing.www.loginlightdemo.MainActivity">
     <ImageView
         android:id="@+id/animation_iv"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_gravity="center"
         android:layout_margin="10dp"
         android:src="@drawable/progress" />

 </android.support.constraint.ConstraintLayout>

activity_main.xml

3.使用代码来播放帧动画

注意:不能再onCreate()方法中进行动画的播放,动画依附于window,在onCreate()时期,window还没有初始化完成

会使动画没有运行而是停留在第一帧，那是因为AnimationDrawable播放动画是依附在window上面，而在Activity onCreate方法中调用时Window还未初始化完毕，所有才会停留在第一帧，要想实现播放必须在onWindowFocusChanged中添加如下代码：

 public class MainActivity extends AppCompatActivity {

     private ImageView imageView;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         imageView = (ImageView) findViewById(R.id.animation_iv);

     }

     @Override
     public void onWindowFocusChanged(boolean hasFocus) {
         super.onWindowFocusChanged(hasFocus);
         imageView.setImageResource(R.drawable.progress);
         AnimationDrawable animationDrawable = (AnimationDrawable) imageView.getDrawable();
         animationDrawable.start();

     }
 }

MainActivity.java