获取屏幕尺寸，大于7为平板，小于7为手机

/**
 * 获取屏幕物理尺寸
 * @return
 */
private double getScreenSize(){
    DisplayMetrics dm = new DisplayMetrics();
    ((Activity)getContext()).getWindowManager().getDefaultDisplay().getMetrics(dm);
    double x = Math.pow(dm.widthPixels/dm.xdpi, 2);
    double y = Math.pow(dm.heightPixels/dm.ydpi, 2);
    double screenInches = Math.sqrt(x+y);

    return screenInches;
}