如何正确创建自定义的动画绘图？

Question

背景

我一直在很多地方进行搜索，以了解如何在不动画视图且不使用内置可绘制对象的情况下对可绘制对象进行动画处理。

原因是我需要在可绘制对象中准备自定义动画，并且稍后我可能对此有不同的要求。

现在，我正在制作一个基本的动画可绘制对象，它只在其中旋转给定的位图。

我已将其设置在 imageView 上，但我希望能够在任何类型的视图上使用它，甚至是覆盖 onDraw 函数的自定义视图。

问题

无论视图的大小是多少，我都不知道如何在不被剪切的情况下显示可绘制对象。这是我所看到的：

代码

这是代码：

private class CircularAnimatedDrawable extends Drawable implements Animatable {
    private static final Interpolator ANGLE_INTERPOLATOR = new LinearInterpolator();
    private static final int ANGLE_ANIMATOR_DURATION = 2000;
    private final RectF fBounds = new RectF();
    private float angle = 0;
    private ObjectAnimator mObjectAnimatorAngle;
    private final Paint mPaint;
    private boolean mRunning;
    private final Bitmap mBitmap;

    public CircularAnimatedDrawable(final Bitmap bitmap) {
        this.mBitmap = bitmap;
        mPaint = new Paint();
        setupAnimations();
    }

    public float getAngle() {
        return this.angle;
    }

    public void setAngle(final float angle) {
        this.angle = angle;
        invalidateSelf();
    }

    @Override
    public Callback getCallback() {
        return mCallback;
    }

    @Override
    public void draw(final Canvas canvas) {
        canvas.save();
        canvas.rotate(angle);
        canvas.drawBitmap(mBitmap, 0, 0, mPaint);
        canvas.restore();
    }

    @Override
    public void setAlpha(final int alpha) {
        mPaint.setAlpha(alpha);
    }

    @Override
    public void setColorFilter(final ColorFilter cf) {
        mPaint.setColorFilter(cf);
    }

    @Override
    public int getOpacity() {
        return PixelFormat.TRANSPARENT;
    }

    @Override
    protected void onBoundsChange(final Rect bounds) {
        super.onBoundsChange(bounds);
        fBounds.left = bounds.left;
        fBounds.right = bounds.right;
        fBounds.top = bounds.top;
        fBounds.bottom = bounds.bottom;
    }

    private void setupAnimations() {
        mObjectAnimatorAngle = ObjectAnimator.ofFloat(this, "angle", 360f);
        mObjectAnimatorAngle.setInterpolator(ANGLE_INTERPOLATOR);
        mObjectAnimatorAngle.setDuration(ANGLE_ANIMATOR_DURATION);
        mObjectAnimatorAngle.setRepeatMode(ValueAnimator.RESTART);
        mObjectAnimatorAngle.setRepeatCount(ValueAnimator.INFINITE);
    }

    @Override
    public void start() {
        if (isRunning())
            return;
        mRunning = true;
        mObjectAnimatorAngle.start();
        invalidateSelf();
    }

    @Override
    public void stop() {
        if (!isRunning())
            return;
        mRunning = false;
        mObjectAnimatorAngle.cancel();
        invalidateSelf();
    }

    @Override
    public boolean isRunning() {
        return mRunning;
    }

}

和用法：

    final ImageView imageView = (ImageView) findViewById(R.id.imageView);
    final Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.spinner_76_inner_holo);

    final CircularAnimatedDrawable circularAnimatedDrawable = new CircularAnimatedDrawable(bitmap);
    circularAnimatedDrawable.setCallback(imageView);
    circularAnimatedDrawable.start();
    imageView.setImageDrawable(circularAnimatedDrawable);

问题

如何设置它以使可绘制对象适合视图？

我应该使用位图大小吗？fBounds？两个都？或者也许是别的什么？

Answer 1

尝试一下您的 Drawable 的修改版本：

class CircularAnimatedDrawable extends Drawable implements Animatable, TimeAnimator.TimeListener {
    private static final float TURNS_PER_SECOND = 0.5f;
    private Bitmap mBitmap;
    private boolean mRunning;
    private TimeAnimator mTimeAnimator = new TimeAnimator();
    private Paint mPaint = new Paint();
    private Matrix mMatrix = new Matrix();

    public CircularAnimatedDrawable(final Bitmap bitmap) {
        mBitmap = bitmap;
        mTimeAnimator.setTimeListener(this);
    }
    @Override
    public void draw(final Canvas canvas) {
        canvas.drawBitmap(mBitmap, mMatrix, mPaint);
    }
    @Override
    protected void onBoundsChange(Rect bounds) {
        Log.d(TAG, "onBoundsChange " + bounds);
        mMatrix.setRectToRect(new RectF(0, 0, mBitmap.getWidth(), mBitmap.getHeight()),
                new RectF(bounds),
                Matrix.ScaleToFit.CENTER);
    }
    @Override
    public void onTimeUpdate(TimeAnimator animation, long totalTime, long deltaTime) {
        Rect b = getBounds();
        mMatrix.postRotate(360 * TURNS_PER_SECOND * deltaTime / 1000, b.centerX(), b.centerY());
        invalidateSelf();
    }
    @Override
    public void setAlpha(final int alpha) {
        mPaint.setAlpha(alpha);
    }
    @Override
    public void setColorFilter(final ColorFilter cf) {
        mPaint.setColorFilter(cf);
    }
    @Override
    public int getOpacity() {
        return PixelFormat.TRANSPARENT;
    }
    @Override
    public void start() {
        if (isRunning())
            return;
        mRunning = true;
        mTimeAnimator.start();
        invalidateSelf();
    }
    @Override
    public void stop() {
        if (!isRunning())
            return;
        mRunning = false;
        mTimeAnimator.cancel();
        invalidateSelf();
    }
    @Override
    public boolean isRunning() {
        return mRunning;
    }
}

编辑：没有 Animator 内容的版本（使用 [un]scheduleSelf），注意它使用 View 的 Drawable.Callback 机制，因此通常无法直接从 onCreate 启动，其中 View 还没有附加处理程序

class CircularAnimatedDrawable extends Drawable implements Animatable, Runnable {
    private static final float TURNS_PER_SECOND = 0.5f;
    private static final long DELAY = 50;
    private Bitmap mBitmap;
    private long mLastTime;
    private boolean mRunning;
    private Paint mPaint = new Paint();
    private Matrix mMatrix = new Matrix();

    public CircularAnimatedDrawable(final Bitmap bitmap) {
        mBitmap = bitmap;
    }
    @Override
    public void draw(final Canvas canvas) {
        canvas.drawBitmap(mBitmap, mMatrix, mPaint);
    }
    @Override
    protected void onBoundsChange(Rect bounds) {
        Log.d(TAG, "onBoundsChange " + bounds);
        mMatrix.setRectToRect(new RectF(0, 0, mBitmap.getWidth(), mBitmap.getHeight()),
                new RectF(bounds),
                Matrix.ScaleToFit.CENTER);
    }
    @Override
    public void setAlpha(final int alpha) {
        mPaint.setAlpha(alpha);
    }
    @Override
    public void setColorFilter(final ColorFilter cf) {
        mPaint.setColorFilter(cf);
    }
    @Override
    public int getOpacity() {
        return PixelFormat.TRANSPARENT;
    }
    @Override
    public void start() {
        if (isRunning())
            return;
        mRunning = true;
        mLastTime = SystemClock.uptimeMillis();
        scheduleSelf(this, 0);
        invalidateSelf();
    }
    @Override
    public void stop() {
        if (!isRunning())
            return;
        mRunning = false;
        unscheduleSelf(this);
        invalidateSelf();
    }
    @Override
    public boolean isRunning() {
        return mRunning;
    }
    @Override
    public void run() {
        long now = SystemClock.uptimeMillis();
        Rect b = getBounds();
        long deltaTime = now - mLastTime;
        mLastTime = now;
        mMatrix.postRotate(360 * TURNS_PER_SECOND * deltaTime / 1000, b.centerX(), b.centerY());
        scheduleSelf(this, now + DELAY);
        invalidateSelf();
    }
}