是不是发现原来这段代码：
#pragma mark -
#pragma mark - alert delegate
- (void) willPresentAlertView:(UIAlertView *)alertView
{
for (UIView *subViewin alertView.subviews)
{
UILabel *tmpLabel = (UILabel *)subView;
tmpLabel.textAlignment =NSTextAlignmentLeft;
}
}
在iOS7.0及以上版本不能用（说明苹果对私有api管理越来越严格，猜测），如果还想uialertview文字对其要费一些心思了。
如果你有这样的需求:
1>message 信息显示居左对齐，如下图（iOS6.0和iOS7.1显示）
2>在iOS7.0以下版本标题居中，message居左（如上图）。
我们对上述代理方法稍作更改如下：
#pragma mark -
#pragma mark - alert delegate
- (void) willPresentAlertView:(UIAlertView *)alertView
{
//由于不希望标题也居左
NSInteger labelIndex = 1;
//在ios7.0一下版本这个方法是可以的
for (UIView *subViewin alertView.subviews)
{
if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_6_1)
{
if ([subView isKindOfClass: [UILabelclass]])
{
if (labelIndex > 1)
{
UILabel *tmpLabel = (UILabel *)subView;
tmpLabel.textAlignment =NSTextAlignmentLeft;
}
//过滤掉标题
labelIndex ++;
}
}
}
}
但这只能在ios7.0以下版本可以生效；如果是8.0，处理方式还不一样，具体如下：
- (void) showAlertWithMessage:(NSString *) message
{
//8.0
if (NSFoundationVersionNumber > NSFoundationVersionNumber_iOS_7_1) {
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"ffff"message:message preferredStyle:UIAlertControllerStyleAlert];
NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
//paragraphStyle.lineBreakMode = NSLineBreakByWordWrapping;
paragraphStyle.alignment = NSTextAlignmentLeft;
//行间距
paragraphStyle.lineSpacing = 5.0;
NSDictionary * attributes = @{NSFontAttributeName : [UIFont systemFontOfSize:18.0], NSParagraphStyleAttributeName : paragraphStyle};
NSMutableAttributedString *attributedTitle = [[NSMutableAttributedString alloc] initWithString:message];
[attributedTitle addAttributes:attributes range:NSMakeRange(0, message.length)];
[alertController setValue:attributedTitle forKey:@"attributedMessage"];//attributedTitle\attributedMessage
//end ---
UIAlertAction *defaultAction1 = [UIAlertAction actionWithTitle:@"cancel"
style: UIAlertActionStyleDefault
handler:^(UIAlertAction *action) {
UITextField *textField = alertController.textFields[0];
NSLog(@"text was %@", textField.text);
}];
UIAlertAction *defaultAction2 = [UIAlertAction actionWithTitle:@"ok"
style: UIAlertActionStyleDefault
handler:^(UIAlertAction *action) {
NSLog(@"ok btn");
[alertControllerdismissViewControllerAnimated:YES completion:nil];
}];
[alertController addAction:defaultAction1];
[alertController addAction:defaultAction2];
//添加textfield
UIViewController *rootViewController = [UIApplicationsharedApplication].keyWindow.rootViewController;
[rootViewController presentViewController:alertController animated: YES completion: nil];
}else{
UIAlertView *tmpAlertView = [[UIAlertView alloc] initWithTitle:@"测试换行"
message:message
delegate:self
cancelButtonTitle:nil
otherButtonTitles:@"知道了", nil];
//如果你的系统大于等于7.0
if (floor(NSFoundationVersionNumber) > NSFoundationVersionNumber_iOS_6_1)
{
CGSize size = [self.messageString sizeWithFont:[UIFont systemFontOfSize:15] constrainedToSize:CGSizeMake(240, 1000) lineBreakMode:NSLineBreakByTruncatingTail];
UILabel *textLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 240, size.height)];
textLabel.font = [UIFont systemFontOfSize:15];
textLabel.textColor = [UIColor blackColor];
textLabel.backgroundColor = [UIColor clearColor];
textLabel.lineBreakMode = NSLineBreakByWordWrapping;
textLabel.numberOfLines = 0;
textLabel.textAlignment = NSTextAlignmentLeft;
textLabel.text = self.messageString;
[tmpAlertView setValue:textLabel forKey:@"accessoryView"];
//这个地方别忘了把alertview的message设为空
tmpAlertView.message = @"";
}
[tmpAlertView show];
}
}
这样的话就可以了。
调用这个方法：
- (void)viewDidLoad
{
[superviewDidLoad];
self.view.backgroundColor = [UIColorgrayColor];
self.messageString =@"1.第一行我是3个子\n2.第二行我是好几个字反正目的是为了和第一行区分开来\n3.哈哈我是陪衬的";
UIButton *alertBtn = [[UIButtonalloc] initWithFrame:CGRectMake(0,200, 320, 40)];
[alertBtn setTitle:@"点我啊，我会alert" forState:UIControlStateNormal];
alertBtn.backgroundColor = [UIColorredColor];
[alertBtn addTarget:selfaction:@selector(alertBtnTapped)forControlEvents:UIControlEventTouchUpInside];
[self.viewaddSubview:alertBtn];
}
这里别忘声明一个属性self.messageString
