Question

我试图添加一个视图，当用户按住按钮时，该视图将从小屏幕扩展到整个屏幕。视图实际上将是一个圆圈，但只是在测试时我将它保持为正方形。

我在MotionEvent.TOUCH_DOWN上有动画代码：

if (abortIndicatorView == null)
    abortIndicatorView = new View(this);

FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(50, 50);
params.gravity = Gravity.CENTER_VERTICAL | Gravity.CENTER_HORIZONTAL;
abortIndicatorView.setLayoutParams(params);
abortIndicatorView.setBackgroundColor(0x80FF0000);
((FrameLayout)findViewById(android.R.id.content)).addView(abortIndicatorView);

double height = Resources.getSystem().getDisplayMetrics().heightPixels;
double width = Resources.getSystem().getDisplayMetrics().widthPixels;
final float radius = (float)Math.sqrt(Math.pow(width, 2) + Math.pow(height, 2)) / 2;
Log.i(TAG, "Radius: " + radius);

abortIndicatorView.startAnimation(new Animation() {
    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        abortIndicatorView.getLayoutParams().width = (int) (radius * interpolatedTime);
        abortIndicatorView.getLayoutParams().height = (int) (radius * interpolatedTime);
    }

    @Override
    public boolean willChangeBounds() {
        return true;
    }
});

但它没有动画效果，视图会以50,50的大小和中心添加，但没有别的。

Answer 1

在abortIndicatorView.requestLayout();中添加applyTransformation并为动画设置持续时间。

Animation animation = new Animation() {
        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            abortIndicatorView.getLayoutParams().width = (int) (radius * interpolatedTime);
            abortIndicatorView.getLayoutParams().height = (int) (radius * interpolatedTime);
            abortIndicatorView.requestLayout();// Add this line
        }

        @Override
        public boolean willChangeBounds() {
            return true;
        }
    };
animation.setDuration(1000);

abortIndicatorView.startAnimation(animation);

查看动画不动画

1 个答案: