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

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <animation-list android:oneshot="false"
 3 
 4   xmlns:android="http://schemas.android.com/apk/res/android">
 5     <item android:duration="50" android:drawable="@drawable/progressbar34" />
 6     <item android:duration="50" android:drawable="@drawable/progressbar33" />
 7     <item android:duration="50" android:drawable="@drawable/progressbar32" />
 8     <item android:duration="50" android:drawable="@drawable/progressbar31" />
 9     <item android:duration="50" android:drawable="@drawable/progressbar30" />
10     <item android:duration="50" android:drawable="@drawable/progressbar29" />
11     <item android:duration="50" android:drawable="@drawable/progressbar28" />
12     <item android:duration="50" android:drawable="@drawable/progressbar27" />
13     <item android:duration="50" android:drawable="@drawable/progressbar26" />
14     <item android:duration="50" android:drawable="@drawable/progressbar25" />
15     <item android:duration="50" android:drawable="@drawable/progressbar24" />
16     <item android:duration="50" android:drawable="@drawable/progressbar23" />
17     <item android:duration="50" android:drawable="@drawable/progressbar22" />
18     <item android:duration="50" android:drawable="@drawable/progressbar21" />
19     <item android:duration="50" android:drawable="@drawable/progressbar20" />
20     <item android:duration="50" android:drawable="@drawable/progressbar19" />
21     <item android:duration="50" android:drawable="@drawable/progressbar18" />
22     <item android:duration="50" android:drawable="@drawable/progressbar17" />
23     <item android:duration="50" android:drawable="@drawable/progressbar16" />
24     <item android:duration="50" android:drawable="@drawable/progressbar15" />
25     <item android:duration="50" android:drawable="@drawable/progressbar14" />
26     <item android:duration="50" android:drawable="@drawable/progressbar13" />
27     <item android:duration="50" android:drawable="@drawable/progressbar12" />
28     <item android:duration="50" android:drawable="@drawable/progressbar11" />
29     <item android:duration="50" android:drawable="@drawable/progressbar10" />
30     <item android:duration="50" android:drawable="@drawable/progressbar9" />
31     <item android:duration="50" android:drawable="@drawable/progressbar8" />
32     <item android:duration="50" android:drawable="@drawable/progressbar7" />
33     <item android:duration="50" android:drawable="@drawable/progressbar6" />
34     <item android:duration="50" android:drawable="@drawable/progressbar5" />
35     <item android:duration="50" android:drawable="@drawable/progressbar4" />
36     <item android:duration="50" android:drawable="@drawable/progressbar3" />
37     <item android:duration="50" android:drawable="@drawable/progressbar2" />
38     <item android:duration="50" android:drawable="@drawable/progressbar1" />
39 </animation-list>

progress.xml

2.指定存放该动画的容器,使用imageView来充当

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent"
 6     tools:context="com.jing.www.loginlightdemo.MainActivity">
 7     <ImageView
 8         android:id="@+id/animation_iv"
 9         android:layout_width="wrap_content"
10         android:layout_height="wrap_content"
11         android:layout_gravity="center"
12         android:layout_margin="10dp"
13         android:src="@drawable/progress" />
14 
15 </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：

 1 public class MainActivity extends AppCompatActivity {
 2 
 3     private ImageView imageView;
 4 
 5     @Override
 6     protected void onCreate(Bundle savedInstanceState) {
 7         super.onCreate(savedInstanceState);
 8         setContentView(R.layout.activity_main);
 9         imageView = (ImageView) findViewById(R.id.animation_iv);
10 
11     }
12 
13     @Override
14     public void onWindowFocusChanged(boolean hasFocus) {
15         super.onWindowFocusChanged(hasFocus);
16         imageView.setImageResource(R.drawable.progress);
17         AnimationDrawable animationDrawable = (AnimationDrawable) imageView.getDrawable();
18         animationDrawable.start();
19 
20     }
21 }

MainActivity.java