帧动画Drawable Animation入门

标签：androidoneshot   onwindowfocuschanged   animationdrawable   

Drawable Animation

Drawable animation lets you load a series of Drawable resources one after another to create an animation. This is a traditional animation in the sense that it is created with a sequence of different images, played in order, like a roll of film. TheAnimationDrawableclass is the basis for Drawable animations.

  Drawable animation是一个一个的加载一些列的图片来创建动画的，他是一种传统的动画，事实上就是一个不同图片的序列AnimationDrawable是Drawable animations 的基类

While you can define the frames of an animation in your code, using theAnimationDrawableclass API, it‘s more simply accomplished with a single XML file that lists the frames that compose the animation. The XML file for this kind of animation belongs in the res/drawable/ directory of your Android project. In this case, the instructions are the order and duration for each frame of the animation.


 虽然可以使用AnimationDrawable类在代码中定义帧动画，但最好是使用XML文件列出组成动画的所有帧。这个xml文件放在 res/drawable/目录下，事实上，所有的指令就是每一个帧动画的顺序和持续时间

The XML file consists of an<animation-list> element as the root node and a series of child<item> nodes that each define a frame: a drawable resource for the frame and the frame duration. Here‘s an example XML file for a Drawable animation:


   xml文件由根元素 <animation-list>和一系列子元素<item>组成，其中<item>定义了每个帧对应的图片和持续时间，如下：

<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
    android:oneshot="true">
    <item android:drawable="@drawable/rocket_thrust1" android:duration="200" />
    <item android:drawable="@drawable/rocket_thrust2" android:duration="200" />
    <item android:drawable="@drawable/rocket_thrust3" android:duration="200" />
</animation-list>

上面的例子是一个3帧动画， 通过将android:oneshot设置为true，那他就只会循环一次，并停留在最后一个帧上，若为false的话，就会循环运行

AnimationDrawable rocketAnimation;

public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  ImageView rocketImage = (ImageView) findViewById(R.id.rocket_image);
  rocketImage.setBackgroundResource(R.drawable.rocket_thrust);
  rocketAnimation = (AnimationDrawable) rocketImage.getBackground();
}

public boolean onTouchEvent(MotionEvent event) {
  if (event.getAction() == MotionEvent.ACTION_DOWN) {
    rocketAnimation.start();
    return true;
  }
  return super.onTouchEvent(event);
}

注意：start()方法不能在你的Activity的onCreate()方法中调用，因为那时候AnimationDrawable尚未完全附着于窗口。如果你必须立刻调用动画，切没有交互的话，可以在onWindowFocusChanged()中调用。因为这个方法是窗口获得焦点时调用的

For more information on the XML syntax, available tags and attributes, see Animation Resources.


帧动画Drawable Animation入门

标签：androidoneshot   onwindowfocuschanged   animationdrawable   

原文地址：http://blog.csdn.net/candicelijx/article/details/45919141