Passing value from activity to view class

Question

I have an activity in which there are 3 checkboxes in different views. These checkboxes are to pick up a color.

In the DrawingView class, I have to draw on my canvas with the color that is checked. What I want is to pass an integer value from the activity to the view class and set the color of paint accordingly. itried using getter and setters, but I get black color. I suppose this is because the color is being set in the constructor itself, and it does not change when I check any box.

Please refer this for updates in the below code

Code:

MainActivity: the color/checkbox is selected here. And the drawing is to be done in the layout of this activity itself.

        carImageView.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View view, MotionEvent motionEvent) {
            drawingView=new DrawingView(carImageView.getContext());
            drawingView=new DrawingView(carImageView.getContext(),null);
            drawingView.setColor(color);
            return false;
        }
    });


  scratchesCb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
      @Override
      public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
          if(b)
          {
              color=1;
              chipsCb.setChecked(false);
              dentsCb.setChecked(false);
          }
      }
  });
    chipsCb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
            if(b)
            {
                color=2;
                scratchesCb.setChecked(false);
                dentsCb.setChecked(false);
            }
        }
    });
    dentsCb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
            if(b)
            {
                color=3;
                chipsCb.setChecked(false);
                scratchesCb.setChecked(false);
            }
        }
    });
}

View Class:

   public DrawingView(Context context, @Nullable AttributeSet attrs) {
   super(context, attrs);
    mPaint=new Paint();
    if(color==1)
        mPaint.setColor(Color.RED);
    else if(color==2)
        mPaint.setColor(Color.BLUE);
    else if(color==3)
        mPaint.setColor(Color.GREEN);
    this.context=context;
    mPath=new Path();
    mPaint.setAntiAlias(true);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeJoin(Paint.Join.MITER);
    mPaint.setStrokeWidth(5f);
}
     public void setColor(int color){
    this.color=color;
}
public int getColor(){
    return this.color;
}

Edit

I don't necessarily want to use the exact same code. All I want is to change paint color when a checkbox is selected to be able to draw on an image view. Any other approach is welcome.

user_2735471 · Answer

You need to call invalidate() on the View to make it update.

Try this,

final DrawingView drawingView = new DrawingView(carImageView.getContext());

carImageView.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {
        drawingView.setColor(color);
        return false;
    }
});


scratchesCb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
  @Override
  public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
      if(b)
      {
          color = 1;
          drawingView.setColor(color);

          chipsCb.setChecked(false);
          dentsCb.setChecked(false);
      }
  }
});

chipsCb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
    @Override
    public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
        if(b)
        {
            color = 2;
            drawingView.setColor(color);

            scratchesCb.setChecked(false);
            dentsCb.setChecked(false);
        }
    }
});


dentsCb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
    @Override
    public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
        if(b)
        {
            color = 3;
            drawingView.setColor(color);

            chipsCb.setChecked(false);
            scratchesCb.setChecked(false);
        }
    }
});

DrawingView.java

public DrawingView(Context context) {
    super(context);
    this.context = context;
    init();
}

public DrawingView(Context context, @Nullable AttributeSet attrs) {
    super(context, attrs);
    this.context=context;
    init();
}

private void init() {
    mPath=new Path();

    mPaint = new Paint();
    mPaint.setAntiAlias(true);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeJoin(Paint.Join.MITER);
    mPaint.setStrokeWidth(5f);
    setColor(color);
}


public void setColor(int color){
    this.color=color;
    if(color==1)
        mPaint.setColor(Color.RED);
    else if(color==2)
        mPaint.setColor(Color.BLUE);
    else if(color==3)
        mPaint.setColor(Color.GREEN);

    // Call invalidate
    invalidate();
}

Passing value from activity to view class

Edit

5 Answers