public class ViewPagerIndicator extends LinearLayout {

private Paint mPaint;

private Path mPath;//構造三角形類

private static final float RADIO=1/6F;

private int mTriangleWidth;

private int mTriangleHeight;

private int mInitTranslationX;//三角形的初始偏移位置，及第一次出現(xiàn)的X坐標

private int mTranslationX=0;//隨著手指滑動，三角形會移動，該數(shù)據(jù)表示移動

public ViewPagerIndicator(Context context){

super(context);

}

public ViewPagerIndicator(Context context, AttributeSet attrs) {

super(context, attrs);

//初始化畫筆

mPaint=new Paint();

mPaint.setAntiAlias(true);

mPaint.setColor(Color.parseColor("#ffffffff"));

mPaint.setStyle(Style.FILL);

}

protected void dispatchDraw(Canvas canvas){

canvas.save();

canvas.translate(mInitTranslationX+ mTranslationX, getHeight());

canvas.drawPath(mPath, mPaint);

canvas.restore();

super.dispatchDraw(canvas);

}

@Override

protected void onSizeChanged(int w,int h,int oldw,int oldh){

super.onSizeChanged(w, h, oldw, oldh);

mTriangleWidth=(int)( w/3*RADIO);

mInitTranslationX=w/3/2-mTriangleWidth/2;

initTriangle();

}

//初始化三角形

private void initTriangle() {

mPath=new Path();

mTriangleHeight=mTriangleWidth/2;

mPath.moveTo(0, 0);//應該是相對坐標

mPath.lineTo(mTriangleWidth, 0);

mPath.lineTo(mTriangleWidth/2,-mTriangleHeight);

mPath.close();

}

}