UIButton 中，文字和图片共存

其实只是设置背景图片而已。

UIButton *btnCommit = [UIButton buttonWithType:UIButtonTypeCustom];

    [btnCommit.titleLabel setFont:[UIFont systemFontOfSize:16]];//这句话不存在的话，文字会显示不出来

    [btnCommit setFrame:CGRectMake(5, 5, 45, 35)];

    [btnCommit setTitle:@"注册" forState:UIControlStateNormal];

    [btnCommit setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];

    [btnCommit setBackgroundImage:[UIImage imageNamed:@"icon_btn_other_click"] forState:UIControlStateNormal];

    [btnCommit setBackgroundImage:[UIImage imageNamed:@"icon_btn_other"] forState:UIControlStateHighlighted];

    [btnCommit addTarget:self action:@selector(commit) forControlEvents:UIControlEventTouchUpInside];