UIButton左对齐

项目中有时候会用到这个小功能, 有一次面试时候遇到提到这个问题, 在此记录一下

UIButton左对齐其实直接设置属性就好了, contentHorizontalAlignment

但是设置contentHorizontalAlignment属性后, 文字会贴在边框上面

所以这里需要调节一下contentEdgeInsets

UIButton *leftBtn = [[UIButton alloc] initWithFrame:CGRectMake(50, 100, 150, 50)];
    leftBtn.backgroundColor = [UIColor redColor];
    [leftBtn setTitle:@"标题左对齐" forState:UIControlStateNormal];
    [leftBtn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    //直接设置contentHorizontalAlignment属性就好
    leftBtn.contentHorizontalAlignment = UIControlContentHorizontalAlignmentLeft;
    //但是设置contentHorizontalAlignment属性后, 文字会贴在边框上面
    //所以这里需要调节一下contentEdgeInsets
    leftBtn.contentEdgeInsets = UIEdgeInsetsMake(0,5, 0, 0);
    [self.view addSubview:leftBtn];