Android 幀動畫什麼時候中止播放

關於android幀動畫沒有提供結束播放的接口回調錶示不理解，也許是基於播放動畫的時候，系統在幹其餘事情，沒法確切地保證動畫在totalDuration時間內播放完畢等。若是有哪位前輩知道緣由，請不吝指教。    

儘管android沒有爲幀動畫提供結束播放的接口，咱們仍是能夠經過一些其餘方式來作到。

方式一，當動畫開始start以後，咱們能夠經過檢測是否到達幀動畫的最後一幀，來肯定動畫是否播完。這種方式能夠保證動畫播完。

方式二，重寫AnimationDrawable，得到totalDuration，而後動畫start以後的totalDuration，調用結束的接口回調onAnimationFinshed()。爲何必須重寫呢？由於，AnimationDrawable僅提供了每一幀的duration，而不能直接得到動畫總的duration。

固然還有一些變種的方法，可是其大致思路都應該差很少。至於動畫是否流暢播放，這要取決於你播放動畫的時候，系統的繁忙程度。

下面給出例子：

定義幀動畫：

res/anim/effect_animation.xml

<?xml version="1.0" encoding="utf-8"?>
<animation-list android:oneshot="true"  xmlns:android="http://schemas.android.com/apk/res/android">  

  <item android:duration="0" android:drawable="@drawable/curtain_5" />
  <item android:duration="0" android:drawable="@drawable/curtain_4" />
  <item android:duration="0" android:drawable="@drawable/curtain_3" />
  <item android:duration="0" android:drawable="@drawable/curtain_2" />
  <item android:duration="200" android:drawable="@drawable/curtain_0" />
  <item android:duration="0" android:drawable="@drawable/curtain_2" />
  <item android:duration="0" android:drawable="@drawable/curtain_3" />
  <item android:duration="0" android:drawable="@drawable/curtain_4" />
  <item android:duration="0" android:drawable="@drawable/curtain_5" />

</animation-list>

思路一：

private void checkIfAnimationDone() {
        mHandler.postDelayed(new Runnable() {
            public void run() {
                if (mAnimationDrawable.getCurrent() != mAnimationDrawable
                        .getFrame(mAnimationDrawable.getNumberOfFrames() - 1)) {
                    checkIfAnimationDone();
                } else {
                    mHandler.sendEmptyMessage(MSG_ANIMATION_FINISHED);
                }
            }
        }, mDuration);
    };

    private void playAnimation() {
        if (mView == null) {
            mView = mContext.getView();
        }
        mView.setBackgroundResource(R.anim.effect_animation);
        mAnimationDrawable = (AnimationDrawable) mView.getBackground();
        mAnimationDrawable.start();
        for (int i = 0; i < mAnimationDrawable.getNumberOfFrames(); i++) {
            mDuration += mAnimationDrawable.getDuration(i);
        }
        checkIfAnimationDone();
    }

 private class MainHandler extends Handler {
        @Override
        public void handleMessage(Message msg) {
            if (LOG) {
                Log.v(TAG, "msg id=" + msg.what);
            }
            switch (msg.what) {
                case MSG_ANIMATION_FINISHED:
                    if(mView == null) {
                        break;
                    }
                    mView.setBackgroundResource(0);
                    break;
            default:
                break;
            }
        }
    }

思路二：

The custom animation drawable class:
public abstract class CustomAnimationDrawableNew extends AnimationDrawable {

	// Handles the animation callback.
	Handler mAnimationHandler;

	public CustomAnimationDrawableNew(AnimationDrawable aniDrawable) {
	    // Add each frame to our animation drawable
	    for (int i = 0; i < aniDrawable.getNumberOfFrames(); i++) {
		this.addFrame(aniDrawable.getFrame(i), aniDrawable.getDuration(i));
	    }
	}

	@Override
	public void start() {
	    super.start();
	    /*
	     * Call super.start() to call the base class start animation method.
	     * Then add a handler to call onAnimationFinish() when the total
	     * duration for the animation has passed
	     */

	    mAnimationHandler = new Handler();
	    mAnimationHandler.postDelayed(new Runnable() {

		public void run() {
		    onAnimationFinish();
		}
	    }, getTotalDuration());

	}

	/**
	 * Gets the total duration of all frames.
	 * 
	 * @return The total duration.
	 */

	public int getTotalDuration() {

	    int iDuration = 0;

	    for (int i = 0; i < this.getNumberOfFrames(); i++) {
		iDuration += this.getDuration(i);
	    }

	    return iDuration;
	}

	/**
	 * Called when the animation finishes.
	 */

	public abstract void onAnimationFinish();
}

Use this class:
ImageView iv = (ImageView) findViewById(R.id.iv_testing_testani);

    iv.setOnClickListener(new OnClickListener() {
        public void onClick(final View v) {

            // Pass our animation drawable to our custom drawable class
            CustomAnimationDrawableNew cad = new CustomAnimationDrawableNew(
                    (AnimationDrawable) getResources().getDrawable(
                            R.drawable.anim_test)) {
                @Override
                public void onAnimationFinish() {
                    // Animation has finished...
                }
            };

            // Set the views drawable to our custom drawable
            v.setBackgroundDrawable(cad);

            // Start the animation
            cad.start();
        }
    });

上述例子僅給出了其思路，若是你感興趣，能夠本身動手實驗。