android - 是否有可能在android动画中获取当前帧数

Question

我正在开发一个应用程序，我想在加载几帧后更改 TextView ，例如第一个 TextView 将是默认的，然后在加载 4 帧后 TextView 应该更改，然后在加载 9 帧后再次更改 TextView 应该更改.我该怎么做？

Answer 1

您可以通过覆盖 AnimationDrawable 类的 selectDrawable(int idx) 方法来实现。为此，您应该创建自定义类，它扩展 AnimationDrawable 声明接口(interface) OnFrameChangeListener 并在帧更改时引发 onFrameChanged() 方法，如下所示:

公共(public)类 ExtendedAnimationDrawable 扩展 AnimationDrawable {

public interface OnFrameChangeListener {
    void onFrameChanged(int numOfFrame);
}

private OnFrameChangeListener mFrameChangeListener;

public ExtendedAnimationDrawable(AnimationDrawable aniDrawable) {
    for (int i = 0; i < aniDrawable.getNumberOfFrames(); i++) {
        this.addFrame(aniDrawable.getFrame(i), aniDrawable.getDuration(i));
    }
}

public void setFrameChangeListener(OnFrameChangeListener frameChangeListener) {
    this.mFrameChangeListener = frameChangeListener;
}

@Override
public boolean selectDrawable(int idx) {
    boolean result = super.selectDrawable(idx);

    if (mFrameChangeListener != null) {
        mFrameChangeListener.onFrameChanged(idx);
    }

    return result;
}

你可以这样使用它:

View v ;

...

v.setBackgroundResource(R.drawable.animation_list);
ExtendedAnimationDrawable extendedAnimation = new ExtendedAnimationDrawable(
        (AnimationDrawable) ContextCompat.getDrawable(context, R.drawable.animation_list));
extendedAnimation.setFrameChangeListener(new ExtendedAnimationDrawable.OnFrameChangeListener() {
    @Override
    public void onFrameChanged(int numOfFrame) {
        // do your magic here
        // for example
        if (numOfFrame == 4) {
           // change TextView #1
        }
        if (numOfFrame == 4 + 9) {
           // change TextView #2
        }
    }
});

int sdk = android.os.Build.VERSION.SDK_INT;
if(sdk < android.os.Build.VERSION_CODES.JELLY_BEAN) {
    v.setBackgroundDrawable(extendedAnimation);
} else {
    v.setBackground(extendedAnimation);
}

extendedAnimation.start();