- (void)viewDidLayoutSubviews {

    [super viewDidLayoutSubviews];

    CGRect frame = self.tabBar.frame;

    frame.size.height = 55;

    frame.origin.y = self.view.frame.size.height - frame.size.height;

    self.tabBar.frame = frame;

    self.tabBar.backgroundColor = mRGBToColor(0xeaeaea);

    self.tabBar.barStyle = UIBarStyleBlack;

    //此处需要设置barStyle，否则颜色会分成上下两层

}

ios简单更改系统TabBar的高度