Android自定义View标识当前选中的控件(2)

            selected = 0; 
        invalidate(); 
    } 
 
    public void previous() { 
        if (selected > 0) 
            selected--; 
        else 
            selected = count - 1; 
        invalidate(); 
    } 
 
    @Override 
    protected void onDraw(Canvas canvas) { 
        Paint paint = new Paint(); 
        paint.setAntiAlias(true); 
        // 起始位置,实现整体居中 
        float w = canvas.getWidth() - (count * 2 * radii) - space * (count - 1); 
 
        for (int i = 0; i < count; i++) { 
            if (i == selected) 
                paint.setColor(point_seleted_color); 
            else 
                paint.setColor(point_normal_color); 
            canvas.drawCircle(w / 2.f + radii + i * (space + radii + radii), 
                    radii + 1, ((int) radii + 2) / 2, paint); 
        } 
    } 
 
    @Override 
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 
        super.onMeasure(widthMeasureSpec, heightMeasureSpec); 
        setMeasuredDimension(widthMeasureSpec, (int) (radii * 2) + 2); 
    } 
 
    public void setSelected(int selectedId) { 
        if (selectedId >= 0 && selectedId <= count) 
            this.selected = selectedId; 
        else if (selectedId < 0) 
            this.selected = 0;