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androidtouchdrawingdrawrectangle

How to draw rectangle as user draws on screen in android


I want to draw rectangle on the screen as user desires, How can I get the points to draw rectangle from user touch event? I have drawn line using onTouchEvent and paint as below. Like this,drawing lines as user desires I want to draw rectangles, But I could not get the values for this. please help

public class SimpleDrawingView extends View {
private final int paintColor = Color.BLACK;
private Paint drawPaint;
private Path path = new Path();
float pointX;
float pointY;

public SimpleDrawingView(Context context, AttributeSet attrs) {
    super(context, attrs);
    setFocusable(true);
    setFocusableInTouchMode(true);
    setupPaint();
}

private void setupPaint() {
    // Setup paint with color and stroke styles
    drawPaint = new Paint();
    drawPaint.setColor(paintColor);
    drawPaint.setAntiAlias(true);
    drawPaint.setStrokeWidth(5);
    drawPaint.setStyle(Paint.Style.STROKE);
    drawPaint.setStrokeJoin(Paint.Join.ROUND);
    drawPaint.setStrokeCap(Paint.Cap.ROUND);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
     pointX = event.getX();
     pointY = event.getY();
    // Checks for the event that occurs
    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            path.moveTo(pointX, pointY);
            return true;
        case MotionEvent.ACTION_MOVE:
            path.lineTo(pointX, pointY);
            break;
        default:
            return false;
    }
    // Force a view to draw again
    postInvalidate();
    return true;
}
@Override
protected void onDraw(Canvas canvas) {
    canvas.drawPath(path,drawPaint);

}

}


Solution

  • You can also do in this way

    public class SimpleDrawingView extends View {
    private final int paintColor = Color.BLACK;
    private Paint drawPaint;
    float pointX;
    float pointY;
    float startX;
    float startY;
    
    public SimpleDrawingView(Context context, AttributeSet attrs) {
    super(context, attrs);
    setFocusable(true);
    setFocusableInTouchMode(true);
    setupPaint();
    }
    
    private void setupPaint() {
    // Setup paint with color and stroke styles
    drawPaint = new Paint();
    drawPaint.setColor(paintColor);
    drawPaint.setAntiAlias(true);
    drawPaint.setStrokeWidth(5);
    drawPaint.setStyle(Paint.Style.STROKE);
    drawPaint.setStrokeJoin(Paint.Join.ROUND);
    drawPaint.setStrokeCap(Paint.Cap.ROUND);
    }
    
    @Override
     public boolean onTouchEvent(MotionEvent event) {
    pointX = event.getX();
    pointY = event.getY();
    // Checks for the event that occurs
    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            startX = pointX;
            startY = pointY;
            return true;
        case MotionEvent.ACTION_MOVE:
            break;
        default:
            return false;
    }
    // Force a view to draw again
    postInvalidate();
    return true;
    }
    
     @Override
     protected void onDraw(Canvas canvas) {
     canvas.drawRect(startX, startY, pointX, pointY, drawPaint);
      }
    }