自定义视图中画布上的补间动画

Question

我有一个扩展 View 的类，我在 onDraw() 方法中在其画布内绘制了我需要的所有内容，如下所示：

protected void onDraw(Canvas canvas) {
        synchronized (this) {
                float h = mHeight;
                float w = mWidth;

                canvas.drawColor(Color.WHITE);

                float roadLine= (85.0f/100.0f)*h;

                canvas.drawBitmap(mTop, 0, roadLine-mTop.getHeight(), null);

                //this is what I'd like to animate
                canvas.drawBitmap(mSmoke);

        }
    }

How do I make an Animation (tween动画）画在这里？

Answer 1

您无法在另一个类的 onDraw() 方法内绘制 ImageView。

这可能更符合您的需求。

public class SimpleAnimation extends Activity {

Sprite sprite;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    sprite = new Sprite(this);
    setContentView(sprite);
}

class Sprite extends ImageView {

    Bitmap bitmap;
    Paint paint;
    RotateAnimation rotate;
    AlphaAnimation blend;
    ScaleAnimation scale;
    AnimationSet spriteAnimation;

    float centerX;
    float centerY;
    float offsetX;
    float offsetY;

    public Sprite(Context context) {
        super(context);

        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon);
        offsetX = bitmap.getWidth() / 2;
        offsetY = bitmap.getHeight() / 2;

        paint = new Paint();
        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (spriteAnimation == null) {
            centerX = canvas.getWidth() / 2;
            centerY = canvas.getHeight() / 2;
            createAnimation(canvas);
        }
        canvas.drawBitmap(bitmap, centerX - offsetX, centerY - offsetY, paint);
    }

    private void createAnimation(final Canvas canvas) {

        rotate = new RotateAnimation(0, 360, centerX, centerY);
        rotate.setRepeatMode(Animation.REVERSE);
        rotate.setRepeatCount(Animation.INFINITE);
        scale = new ScaleAnimation(0, 2, 0, 2, centerX, centerY);
        scale.setRepeatMode(Animation.REVERSE);
        scale.setRepeatCount(Animation.INFINITE);
        scale.setInterpolator(new AccelerateDecelerateInterpolator());

        spriteAnimation = new AnimationSet(true);
        spriteAnimation.addAnimation(rotate);
        spriteAnimation.addAnimation(scale);
        spriteAnimation.setDuration(10000L);

        startAnimation(spriteAnimation);

    }
  }
}