自定义一个GooView
// 初始化要使用到的资源和对象
private void initView() {
paint = new Paint();
paint.setAntiAlias(true);//边缘更加清晰
paint.setColor(Color.RED);
}
对画笔进行初始化
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (isDisappear) {
return;
}
mStickRadius = fixStickRadius();
// 连接组建数据
float offsetY = mStickCenter.y - mDragCenter.y;
float offsetX = mStickCenter.x - mDragCenter.x;
Double lineK = 0d;
if (offsetX!=0) {
lineK = (double) (offsetY / offsetX);
}
PointF[] mStickPoints = GeometryUtil.getIntersectionPoints(mStickCenter, mStickRadius, lineK);
PointF[] mDragPoints = GeometryUtil.getIntersectionPoints(mDragCenter, mDragRadius, lineK);
PointF mControlorPoint = GeometryUtil.getMiddlePoint(mStickCenter, mDragCenter);
// 绘制拖拽圆
canvas.drawCircle(mDragCenter.x, mDragCenter.y, mDragRadius, paint);
// 如果没有超出最大距离，才绘制固定圆和连接组件
if (!isBrokenConnect) {
// 绘制固定圆
canvas.drawCircle(mStickCenter.x, mStickCenter.y, mStickRadius, paint);
// 绘制连接组件
Path path = new Path();
path.moveTo(mDragPoints[0].x, mDragPoints[0].y);// 移动到起始点
path.quadTo(mControlorPoint.x, mControlorPoint.y, mStickPoints[0].x, mStickPoints[0].y);// 绘制曲线，x1、y1 是控制点，x2、y2是结束点
path.lineTo(mStickPoints[1].x, mStickPoints[1].y);// 绘制直线
path.quadTo(mControlorPoint.x, mControlorPoint.y, mDragPoints[1].x, mDragPoints[1].y);
path.close();// 闭合路径
canvas.drawPath(path, paint);
}
// 绘制参考内容
paint.setStyle(Style.STROKE);// 设置为只绘制边线
paint.setColor(Color.BLUE);// 修改填充颜色
canvas.drawCircle(mStickCenter.x, mStickCenter.y, MAX_DISTANCE, paint);
canvas.drawCircle(mDragPoints[0].x, mDragPoints[0].y, 2, paint);
canvas.drawCircle(mDragPoints[1].x, mDragPoints[1].y, 2, paint);
canvas.drawCircle(mStickPoints[0].x, mStickPoints[0].y, 2, paint);
canvas.drawCircle(mStickPoints[1].x, mStickPoints[1].y, 2, paint);
paint.setStyle(Style.FILL);
paint.setColor(Color.RED);
}
无效的时候就不绘图，
private float fixStickRadius() {
float distance = GeometryUtil.getDistanceBetween2Points(mStickCenter, mDragCenter);
float fraction = distance / MAX_DISTANCE;// 百分比 = 当前的圆心距离 / 最大距离
if (fraction > 1) {
fraction = 1;
}
return evaluate(fraction , mDragRadius, mDragRadius/2);
}
返回一个浮点数，就是拖拽棍子的长度。
mDragCenter这个被不断刷新
// 如果没有超出最大距离，才绘制固定圆和连接组件
if (!isBrokenConnect) {
// 绘制固定圆
canvas.drawCircle(mStickCenter.x, mStickCenter.y, mStickRadius, paint);
// 绘制连接组件
Path path = new Path();
path.moveTo(mDragPoints[0].x, mDragPoints[0].y);// 移动到起始点
path.quadTo(mControlorPoint.x, mControlorPoint.y, mStickPoints[0].x, mStickPoints[0].y);// 绘制曲线，x1、y1 是控制点，x2、y2是结束点
path.lineTo(mStickPoints[1].x, mStickPoints[1].y);// 绘制直线
path.quadTo(mControlorPoint.x, mControlorPoint.y, mDragPoints[1].x, mDragPoints[1].y);
path.close();// 闭合路径
canvas.drawPath(path, paint);
}
如果没有被中断话棍子，path.close();// 闭合路径
case MotionEvent.ACTION_MOVE:
// 移动拖拽圆的位置
float x = event.getX();
float y = event.getY();
updateDragCenter(x, y);
// 如果现在两个圆的距离超过了最大限制，则标识不再绘制连接组件和固定圆
float distance = GeometryUtil.getDistanceBetween2Points(mStickCenter, mDragCenter);
if (distance > MAX_DISTANCE) {
isBrokenConnect = true;
}
invalidate();
更新棍子的长度。重绘
// 松手时，如果没有断开连接，则显示回弹效果
final PointF startPointF = new PointF(mDragCenter.x, mDragCenter.y);
ValueAnimator animator = ValueAnimator.ofFloat(1);
animator.addUpdateListener(new AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator value) {
System.out.println("time="+value.getCurrentPlayTime()+";percent="+value.getAnimatedFraction());
float percent = value.getAnimatedFraction();
PointF newPoint = GeometryUtil.getPointByPercent(startPointF, mStickCenter, percent);
updateDragCenter(newPoint.x, newPoint.y);
}
});
animator.addListener(new AnimatorListener() {
@Override
public void onAnimationStart(Animator arg0) {
}
@Override
public void onAnimationRepeat(Animator arg0) {
}
@Override
public void onAnimationEnd(Animator arg0) {
// 动画播放结束之后，调用监听
if (onDragEventListener!=null) {
onDragEventListener.onReset(false);
}
}
@Override
public void onAnimationCancel(Animator arg0) {
}
});
animator.setDuration(200);
animator.setInterpolator(new OvershootInterpolator(8));
animator.start();
}
invalidate();
break;
没有中断的时候。刷新值
随时随地看视频
