AnimationDrawable 結束回調

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,系統在幹其他事情,無法確切地保證動畫在totalDuration時間內播放完畢等。如果有哪位前輩知道原因,請不吝指教。    

儘管android沒有爲幀動畫提供結束播放的接口,我們還是可以通過一些其他方式來做到。

方式一,當動畫開始start之後,我們可以通過檢測是否到達幀動畫的最後一幀,來確定動畫是否播完。這種方式可以保證動畫播完。

方式二,重寫AnimationDrawable,獲得totalDuration,然後動畫start之後的totalDuration,調用結束的接口回調onAnimationFinshed()。爲什麼必須重寫呢?因爲,AnimationDrawable僅提供了每一幀的duration,而不能直接獲得動畫總的duration。

當然還有一些變種的方法,但是其大體思路都應該差不多。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

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<?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:

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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:

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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();
        }
    });
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