如何在Android中的TextView或EditText中添加动画表情符号

Question

作为问题,我使用ImageSpan将图像添加到TextView中.但是它不能
动画.你有任何建议吗？我尝试扩展AnimationDrawable以将drawable添加到ImageSpan中.但它不起作用

public class EmoticonDrawalbe extends AnimationDrawable {
    private Bitmap bitmap;
    private GifDecode decode;
    private int gifCount;

    public EmoticonDrawalbe(Context context, String source) {
        decode = new GifDecode();
        decode.read(context, source);
        gifCount = decode.getFrameCount();
        if (gifCount <= 0) {
            return;
        }
        for (int i = 0; i < gifCount; i++) {
            bitmap = decode.getFrame(i);
            addFrame(new BitmapDrawable(bitmap), decode.getDelay(i));
        }
        setOneShot(false);
    }

    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);
        start();
    }
}

Answer 1

我会尝试:

• 将动画图像(可能是.gif文件？)拆分为单独的帧,然后将它们组合成一个AnimationDrawable,然后传递给ImageSpan的构造函数.
• Subclass ImageSpan并覆盖该onDraw()方法以添加您自己的逻辑,以根据某种计时器绘制不同的帧.有一个api演示,演示如何使用Movie类加载可能值得研究的动画gif.

Big Edit: 好的,抱歉没有早点回来,但我不得不留出一些时间来自己调查.我玩过它,因为我可能需要一个解决方案,我自己的未来项目之一.不幸的是,我遇到了使用a的类似问题AnimationDrawable,这似乎是由DynamicDrawableSpan(间接超类ImageSpan)使用的缓存机制引起的.

对我来说另一个问题是,似乎没有一个简单的使用无效的Drawable或ImageSpan.Drawable实际上有invalidateDrawable(Drawable)和invalidateSelf()方法,但第一个在我的情况下没有任何影响,而后者只有Drawable.Callback在附加一些魔法时才有效.我找不到任何关于如何使用这个的体面文件......

所以,我更进一步向上逻辑树来解决问题.我必须事先添加一个警告,这很可能不是最佳解决方案,但现在它是我唯一可以上班的.如果你偶尔使用我的解决方案,你可能不会遇到问题,但我会避免用表情符号填满整个屏幕.我不确定会发生什么,但话说回来,我可能甚至都不想知道.

不用多说,这是代码.我添加了一些评论,使其不言自明.它很可能是一个使用不同的Gif解码类/库,但它应该适用于任何在那里.

AnimatedGifDrawable.java

public class AnimatedGifDrawable extends AnimationDrawable {

    private int mCurrentIndex = 0;
    private UpdateListener mListener;

    public AnimatedGifDrawable(InputStream source, UpdateListener listener) {
        mListener = listener;
        GifDecoder decoder = new GifDecoder();
        decoder.read(source);

        // Iterate through the gif frames, add each as animation frame
        for (int i = 0; i < decoder.getFrameCount(); i++) {
            Bitmap bitmap = decoder.getFrame(i);
            BitmapDrawable drawable = new BitmapDrawable(bitmap);
            // Explicitly set the bounds in order for the frames to display
            drawable.setBounds(0, 0, bitmap.getWidth(), bitmap.getHeight());
            addFrame(drawable, decoder.getDelay(i));
            if (i == 0) {
                // Also set the bounds for this container drawable
                setBounds(0, 0, bitmap.getWidth(), bitmap.getHeight());
            }
        }
    }

    /**
     * Naive method to proceed to next frame. Also notifies listener.
     */
    public void nextFrame() {
        mCurrentIndex = (mCurrentIndex + 1) % getNumberOfFrames();
        if (mListener != null) mListener.update();
    }

    /**
     * Return display duration for current frame
     */
    public int getFrameDuration() {
        return getDuration(mCurrentIndex);
    }

    /**
     * Return drawable for current frame
     */
    public Drawable getDrawable() {
        return getFrame(mCurrentIndex);
    }

    /**
     * Interface to notify listener to update/redraw 
     * Can't figure out how to invalidate the drawable (or span in which it sits) itself to force redraw
     */
    public interface UpdateListener {
        void update();
    }

}

AnimatedImageSpan.java

public class AnimatedImageSpan extends DynamicDrawableSpan {

    private Drawable mDrawable;

    public AnimatedImageSpan(Drawable d) {
        super();
        mDrawable = d;
        // Use handler for 'ticks' to proceed to next frame 
        final Handler mHandler = new Handler();
        mHandler.post(new Runnable() {
            public void run() {
                ((AnimatedGifDrawable)mDrawable).nextFrame();
                // Set next with a delay depending on the duration for this frame 
                mHandler.postDelayed(this, ((AnimatedGifDrawable)mDrawable).getFrameDuration());
            }
        });
    }

    /*
     * Return current frame from animated drawable. Also acts as replacement for super.getCachedDrawable(),
     * since we can't cache the 'image' of an animated image.
     */
    @Override
    public Drawable getDrawable() {
        return ((AnimatedGifDrawable)mDrawable).getDrawable();
    }

    /*
     * Copy-paste of super.getSize(...) but use getDrawable() to get the image/frame to calculate the size,
     * in stead of the cached drawable.
     */
    @Override
    public int getSize(Paint paint, CharSequence text, int start, int end, Paint.FontMetricsInt fm) {
        Drawable d = getDrawable();
        Rect rect = d.getBounds();

        if (fm != null) {
            fm.ascent = -rect.bottom; 
            fm.descent = 0; 

            fm.top = fm.ascent;
            fm.bottom = 0;
        }

        return rect.right;
    }

    /*
     * Copy-paste of super.draw(...) but use getDrawable() to get the image/frame to draw, in stead of
     * the cached drawable.
     */
    @Override
    public void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, Paint paint) {
        Drawable b = getDrawable();
        canvas.save();

        int transY = bottom - b.getBounds().bottom;
        if (mVerticalAlignment == ALIGN_BASELINE) {
            transY -= paint.getFontMetricsInt().descent;
        }

        canvas.translate(x, transY);
        b.draw(canvas);
        canvas.restore();

    }

}

用法:

final TextView gifTextView = (TextView) findViewById(R.id.gif_textview);
SpannableStringBuilder sb = new SpannableStringBuilder();
sb.append("Text followed by animated gif: ");
String dummyText = "dummy";
sb.append(dummyText);
sb.setSpan(new AnimatedImageSpan(new AnimatedGifDrawable(getAssets().open("agif.gif"), new AnimatedGifDrawable.UpdateListener() {   
    @Override
    public void update() {
        gifTextView.postInvalidate();
    }
})), sb.length() - dummyText.length(), sb.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
gifTextView.setText(sb);

正如您所看到的,我使用Handler来提供"ticks"以前进到下一帧.这样做的好处是,只有在应该渲染新帧时,它才会触发更新.实际的重绘是通过使包含AnimatedImageSpan的TextView无效来完成的.与此同时,缺点是每当你在同一个TextView中有一堆GIF动画(或者就此而言是多个)时,视图可能会像疯了一样更新......明智地使用它.:)

Answer 2

您可以使用 ObjectAnimator 对 ImageSpan 中的可绘制对象进行动画处理

http://developer.android.com/reference/android/animation/ObjectAnimator.html