如何在屏幕上独立移动两个圆圈？
我有一个应用程序可以在屏幕上画两个圆圈。绘制完成后，我可以移动其中一个圆圈并将其放置在我想要的位置。有没有办法确定我触摸了哪个圆圈，以便我可以移动该特定圆圈？目前我只能在 centerX centerY 的坐标处移动圆。
public boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN: {
if(xyFound == false) {
centreX = (int) ev.getX()-70;
centreY = (int) ev.getY()-70;
xyFound = true;
} else {
centreA = (int) ev.getX()-70;
centreB = (int) ev.getY()-70;
abFound = true;
bothCirclesInPlace = true;
invalidate();
}
}
case MotionEvent.ACTION_MOVE: {
if(xyFound == false){
centreX = (int) ev.getX()-70;
centreY = (int) ev.getY()-70;
xyFound = true;
}else{
centreA = (int) ev.getX()-70;
centreB = (int) ev.getY()-70;
bothCirclesInPlace = true;
invalidate();
} break;
}
。
[更新1]
@Override
public boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN: {
float circ1Val = centreX + centreY;
float circ2Val = centreA + centreB;
float choice1 = circ1Val - (ev.getX() + ev.getY());
float choice2 = circ2Val - (ev.getX() + ev.getY());
float circleToBeMoved = choice1 < choice2 ? ;
。 我不确定计算每个圆圈和触摸事件之间的距离的最佳方法。这是正确的路线吗？或者有更好的方法吗？谢谢
I've an app that paints 2 circles on the screen. once drawn I can move one of the circles around and place where i want. Is there a way to determin which circle I have touched so that I can move that particular circle? At the moment I can only move the circle at co-ords at centreX centreY.
public boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN: {
if(xyFound == false) {
centreX = (int) ev.getX()-70;
centreY = (int) ev.getY()-70;
xyFound = true;
} else {
centreA = (int) ev.getX()-70;
centreB = (int) ev.getY()-70;
abFound = true;
bothCirclesInPlace = true;
invalidate();
}
}
case MotionEvent.ACTION_MOVE: {
if(xyFound == false){
centreX = (int) ev.getX()-70;
centreY = (int) ev.getY()-70;
xyFound = true;
}else{
centreA = (int) ev.getX()-70;
centreB = (int) ev.getY()-70;
bothCirclesInPlace = true;
invalidate();
} break;
}
.
[update1]
@Override
public boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN: {
float circ1Val = centreX + centreY;
float circ2Val = centreA + centreB;
float choice1 = circ1Val - (ev.getX() + ev.getY());
float choice2 = circ2Val - (ev.getX() + ev.getY());
float circleToBeMoved = choice1 < choice2 ? ;
.
I'm not sure the best way to calculate the distance between each of the circles and the touch event. is this on the correct lines? or is there a better way? thanks
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有以下方法：
在
ACTION_DOWN上，您确定哪个圆位于触摸点旁边。因此，您可以计算从(centreX,centreY)到(ev.getX(),ev.getY())以及从(centreA,centreB)< /code> 到(ev.getX(),ev.getY())。如果第一个小于第二个，您将移动第一个圆，否则移动第二个圆（将此选择保存在字段circleToBeMoved中）。如果两个距离都超出阈值（例如圆的半径），您可能想拒绝任何移动。其次，在
ACTION_MOVE上仅移动circleToBeMoved中包含的圆（如果有）。There is the following approach:
On
ACTION_DOWNyou determine which circle lies next to the point touched. Therefore you calculate the distance from(centreX,centreY)to(ev.getX(),ev.getY())and from(centreA,centreB)to(ev.getX(),ev.getY()). If the first is smaller than the second you'll move the first circle otherwise the second circle (save this choice in a fieldcircleToBeMoved). Maybe you want to reject any movement if both distances are beyond a threshold (e.g. radius of the circles).Second, on
ACTION_MOVEonly move the circle contained incircleToBeMoved(if any).