Android 在画布上跟踪触摸输入
我有一个由帆布drawrect制成的5x5正方形游戏板:Android 在画布上跟踪触摸输入,android,canvas,touch,Android,Canvas,Touch,我有一个由帆布drawrect制成的5x5正方形游戏板: protected void onDraw(Canvas canvas) { for (int rowNo = 0; rowNo < nSquares; rowNo++) { paint.setColor(((rowNo & 1) == 0) ? colorA : colorB); for (int colNo = 0; colNo < nSquares; colNo++) {
protected void onDraw(Canvas canvas) {
for (int rowNo = 0; rowNo < nSquares; rowNo++) {
paint.setColor(((rowNo & 1) == 0) ? colorA : colorB);
for (int colNo = 0; colNo < nSquares; colNo++) {
int left = colNo * squareWidth;
int top = rowNo * squareWidth;
Rect areaRect = new Rect(left, top, left + squareWidth, top + squareWidth);
canvas.drawRect(areaRect, paint);
paint.setColor((paint.getColor() == colorA) ? colorB : colorA);
paint.setTextSize((float)(squareWidth*0.8));
RectF bounds = new RectF(areaRect);
String letter = "A";
bounds.right = paint.measureText(letter, 0, letter.length());
bounds.bottom = paint.descent() - paint.ascent();
bounds.left += (areaRect.width() - bounds.right) / 2.0f;
bounds.top += (areaRect.height() - bounds.bottom) / 2.0f;
canvas.drawText(letter, bounds.left, bounds.top - paint.ascent(), paint);
}
}
getSquare在哪里
public int getSquare(int x, int y) {
int row = 0;
int col = 0;
for(int rowNo = 1; rowNo <= nSquares; rowNo++) {
Log.i("Row", "Width: " + squareWidth + " rowNo: " + rowNo + " rowNo*squareW: " + rowNo*squareWidth + " y: " + y);
if(rowNo*squareWidth > y)
{
row = rowNo;
break;
}
}
for (int colNo = 1; colNo <= nSquares; colNo++) {
if(colNo*squareWidth > x)
{
col = colNo;
break;
}
}
Log.i(DEBUG_TAG, "Row: " + row + " Col: " + col);
return (row-1)*nSquares + col;
}
问题是onTouchEvent getX和getY指的是屏幕0,0,但当我绘制正方形0,0,0,0时,它指的是视图原点?我说得对吗?
如何获取相对于游戏板视图的输入位置?
获取屏幕中的视图位置并将其添加/减去到tochEvent x和y位置是否是一种解决方案?我假设onDraw和getSquare属于GameBoardView,而onTouchEvent属于其直接父对象。如果是这样,那么onTouchEvent应该是这样的
public boolean onTouchEvent(MotionEvent event){
int action = MotionEventCompat.getActionMasked(event);
int x = (int)event.getX() - gameBoard.getX();
int y = (int)event.getY() - gameBoard.getY();
Log.i(DEBUG_TAG, "Position: (" + x + ", " + y + ")");
int squareTouched = gameBoard.getSquare(x, y);
}
在视图中,onDraw和onTouchEvent中的x和y都是相对于视图本身的,滚动视图时除外。因为在您的例子中,onTouchEvent属于父对象,onDraw属于子对象,所以我使用View.getX和getY来转换坐标。View.getX返回视图相对于其父视图的x位置加平移x。我无法让gameBoard.getX/Y返回正确的值。我猜动作栏被排除在外了 我现在在屏幕上使用getLocationOnScreen 解决了我的问题
public boolean onTouchEvent(MotionEvent event){
int action = MotionEventCompat.getActionMasked(event);
int x = (int)event.getX() - gameBoard.getX();
int y = (int)event.getY() - gameBoard.getY();
Log.i(DEBUG_TAG, "Position: (" + x + ", " + y + ")");
int squareTouched = gameBoard.getSquare(x, y);
}
@Override
public boolean onTouchEvent(MotionEvent event){
int action = MotionEventCompat.getActionMasked(event);
int boardLocation[] = new int[2];
gameBoard.getLocationOnScreen(boardLocation);
int touchX = (int)event.getX();
int touchY = (int)event.getY();
int x = touchX - boardLocation[0];
int y = touchY - boardLocation[1];
int squareTouched = gameBoard.getSquare(x,y);
}