我正在尝试绘制一个圆圈的动画。在我的自定义视图中,我有
private final Paint mPaint = new Paint() {
{
setDither(true);
setStyle(Paint.Style.STROKE);
setStrokeCap(Paint.Cap.ROUND);
setStrokeJoin(Paint.Join.ROUND);
setColor(Color.BLUE);
setStrokeWidth(30.0f);
setAntiAlias(true);
}
};
...
protected void onDraw(Canvas canvas) {
super.onDraw();
if (mOval == null) {
mOval = new RectF(getLeft(), getTop(), getRight(), getBottom());
}
if (mPath == null) {
mPath = new Path();
mPath.moveTo(0, getHeight() / 2);
}
float sweepAngle = Math.min((float) mElapsedTime / 1000 * 60 * 1, 1) * 360;
if (sweepAngle == 0) {
mPath.reset();
} else if (mCurrentAngle != sweepAngle) {
mPath.arcTo(mOval, mCurrentAngle, sweepAngle);
}
mCurrentAngle = sweepAngle;
canvas.drawPath(mPath, mPaint);
}
每隔一段时间,我就会更新mElapsedTime
和调用invalidate()
. 但是,屏幕上没有绘制任何内容。我尝试了几种变体,但无济于事。有什么我做错了吗?有没有更简单的方法来做到这一点?给定一个圆圈的百分比,我希望能够使圆圈的大部分成为屏幕上绘制的内容。