如何更改 UIAlertView 中的消息对齐方式？

Question

　　当我使用 UIAlertView 时，我发现消息的 textAligment 是 Center。例如，当我写这段代码时：

    UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:nil
                                                   message:@"this is first line     \nsecondLine should be center"
                                                  delegate:nil
                                         cancelButtonTitle:nil
                                         otherButtonTitles:nil, nil];
[alertView show];

效果如下：
如我们所见，文本“这是第一行”在中心，但我想将其更改为左侧。我知道 UILabel 可以更改文本的对齐方式，但我不知道是否可以在 UIAlertView 中更改它。

Answer 1

像这样编辑你的代码。

UIAlertView *alert = [[UIAlertView alloc]initWithTitle:nil
                                               message:nil
                                              delegate:nil
                                     cancelButtonTitle:nil
                                     otherButtonTitles:nil, nil];


UILabel *v = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 80, 40)];
v.text = NSTextAlignmentLeft;
v.numberOfLines = 0;
v.text = @"this is first line\nsecondLine should be center";
[alert setValue:v forKey:@"accessoryView"];
[alert show];

Answer 2

iOS7：对于左对齐，你可以这样做：

NSArray *subViewArray = alertView.subviews;
for(int x = 0; x < [subViewArray count]; x++){

    //If the current subview is a UILabel...
    if([[[subViewArray objectAtIndex:x] class] isSubclassOfClass:[UILabel class]]) {
        UILabel *label = [subViewArray objectAtIndex:x];
        label.textAlignment = NSTextAlignmentLeft;
    }
}

参考：How to make a multiple line, left-aligned UIAlertView?

或者你可以在alertView中添加一个UILabel：

    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Centered Title" message:@"\n\n\n" delegate:self cancelButtonTitle:@"Close" otherButtonTitles:nil];

    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(12.0, 24.0, 250.0, 80.0)];
    label.numberOfLines = 0;
    label.textAlignment = NSTextAlignmentLeft;
    label.backgroundColor = [UIColor clearColor];
    label.textColor = [UIColor whiteColor];
    label.text = @"Here is an example of a left aligned label in a UIAlertView!";
    [alert addSubview:label];
    [alert show];

参考：How to align only the title in UIAlertView