iOS 设置按钮上图下文的方式

 UIButton *tabBtn = [UIButtonbuttonWithType:UIButtonTypeCustom];

        tabBtn.frame = CGRectMake(tabbarBtn_Width * i, 0, tabbarBtn_Width, 43);
        tabBtn.contentHorizontalAlignment = UIControlContentHorizontalAlignmentCenter;//这是图片和文字的布局居中
        [tabBtn setImage:[UIImage imageNamed:tabbarBtn[i]] forState:UIControlStateNormal];
        [tabBtn setImage:[UIImage imageNamed:tabbarBtn_h[i]] forState:UIControlStateSelected];
        [tabBtn setTintColor:[UIColor whiteColor]];

        [tabBtn setTitle:tabarName[i] forState:UIControlStateNormal];

        //设置文字的偏移量，上偏移文字的高度，左偏移图片的宽度，下部和右边不变

        [tabBtn setTitleEdgeInsets:UIEdgeInsetsMake(tabBtn.imageView.frame.size.height,-tabBtn.imageView.frame.size.width, 0,0)];
        //设置图片的偏移量，上偏移图片的高度，左偏移图片的宽度，下部和右边不变
        [tabBtn setImageEdgeInsets:UIEdgeInsetsMake(- 5,0,0, -tabBtn.titleLabel.bounds.size.width + 10)];

        tabBtn.titleLabel.font = [UIFont systemFontOfSize:12.0];