Bonjour, j'ai un problème j'ai crée une vue personnalisée qui se dessine entièrement d'elle même mais sa méthode onDraw n'est jamais appelée

voilà ma classe

package com.example.launcher;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;

import com.example.launcher.PagedView.OnPageChangeListener;

/**
 * TODO: document your custom view class.
 */
public class PageIndicator extends View  implements OnPageChangeListener{

	private static int GREY = 0x7dcccccc;
	private static int WHITE = 0xffffff;
	private int mCurrentPage;
	private int mPageCount;
	private Paint mPaint = new Paint();
	private Rect mSize = new Rect(0,0,0,0);
	private Rect mIndicatorRect = new Rect(0,0,0,0);
	private int mWidth;
	private int mHeight;
	public PageIndicator(Context context) {
		super(context);
		init();
	}

	public PageIndicator(Context context, AttributeSet attrs) {
		super(context, attrs);
		init();
	}

	public PageIndicator(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		init();
	}

	private void init() {
		
	}

	@Override
	public void onPageChange(int index) {
		mCurrentPage = index;
		if(mPageCount > 1)
			mIndicatorRect.offsetTo(index*(mWidth/mPageCount), 0);	
		invalidate();
	}

	@Override
	public void onPageCountChanged(int count) {
		mPageCount = count;
		if(mPageCount > 1)
			mIndicatorRect.right = mIndicatorRect.left + mWidth/mPageCount;
		else
			mIndicatorRect.right = mWidth;
		invalidate();
	}
	@Override
    protected void onSizeChanged(int xNew, int yNew, int xOld, int yOld){
            super.onSizeChanged(xNew, yNew, xOld, yOld);
            mWidth = xNew;
            mHeight = yNew;
            mSize.bottom = mHeight;
    		mSize.right = mHeight;
    		mIndicatorRect.bottom = mHeight;
    		if(mPageCount > 1)
    			mIndicatorRect.right = mWidth/mPageCount;
    		else
    			mIndicatorRect.right = mWidth;
    }
	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
	{
		final int width = MeasureSpec.getSize(widthMeasureSpec);
		final int height = MeasureSpec.getSize(heightMeasureSpec);

		setMeasuredDimension(width, height);
	}
	@Override
	protected void onDraw(Canvas canvas)
	{
		mPaint.setColor(GREY);
		canvas.drawRect(mSize, mPaint);
		mPaint.setColor(WHITE);
		canvas.drawRect(mIndicatorRect, mPaint);
	}
}

Merci d'avance pour vos réponses