Draw rectangle in arbitrary position after touch event in canvas android
User 3353723
CanvasI'm trying to draw a rectangle (should not exceed the canvas size) anywhere in the shape, and if the user touches the shape, a rectangle should be drawn at another random location . I've managed to draw the rectangle, but need help Touch Eventand draw it in random positions.
public class DrawView extends View {
Paint paint = new Paint();
public DrawView(Context context) {
super(context);
}
@Override
public void onDraw(Canvas canvas) {
paint.setColor(Color.BLACK);
paint.setStrokeWidth(3);
canvas.drawRect(30, 30, 80, 80, paint);
paint.setStrokeWidth(0);
paint.setColor(Color.CYAN);
canvas.drawRect(33, 60, 77, 77, paint );
paint.setColor(Color.YELLOW);
canvas.drawRect(33, 33, 77, 60, paint );
}
}
Any help would be greatly appreciated.
Daniel Hussain
You can follow the instructions below:
E.g
public class DrawView extends View {
// here you define hashmap for user touch points
Paint paint = new Paint();
public DrawView(Context context) {
super(context);
}
@Override
public void onDraw(Canvas canvas) {
yourRandomFunction(-99,-99);
}
public void yourRandomFunction(float x , float y ){
//for first time user touch
// if -99 && -99 {
//Calculate random points here.
paint.setColor(Color.BLACK);
paint.setStrokeWidth(3);
canvas.drawRect(30, 30, 80, 80, paint);
paint.setStrokeWidth(0);
paint.setColor(Color.CYAN);
canvas.drawRect(33, 60, 77, 77, paint );
paint.setColor(Color.YELLOW);
canvas.drawRect(33, 33, 77, 60, paint );
// add points to hashmap
}
//else check in hashmap if exist then {
//Calculate random points here.
paint.setColor(Color.BLACK);
paint.setStrokeWidth(3);
canvas.drawRect(30, 30, 80, 80, paint);
paint.setStrokeWidth(0);
paint.setColor(Color.CYAN);
canvas.drawRect(33, 60, 77, 77, paint );
paint.setColor(Color.YELLOW);
canvas.drawRect(33, 33, 77, 60, paint );
// add point to hashmap
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float eventX = event.getX();
float eventY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
//check points in hashmap
return true;
case MotionEvent.ACTION_MOVE:
break;
case MotionEvent.ACTION_UP:
// nothing to do
yourRandomFuncntion(eventX,eventY);
break;
default:
return false;
}
// Schedules a repaint.
invalidate();
return true;
}
}