在 UITextField UI 上调用 UIAlertView 会关闭键盘

Question

我注意到一些非常奇怪的行为。我想在选择UITextField时显示UIAlertView：

[self.addressTextField addTarget:self action:@selector(addressTextFieldSelected) forControlEvents:UIControlEventEditingDidBegin];

调用的方法为：

- (void)addressTextFieldSelected {
    if (!geoPoint) {
        UIAlertView* alertView = [[UIAlertView alloc] initWithTitle:@"Alert" message:@"Text" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
        [alertView show];
    }
}

触摸文本字段时，键盘确实开始向上滑动。但是，当警报视图出现时，键盘将关闭。选择"确定"并关闭警报视图后，文本字段的键盘将向上滑动。

编辑

在其他人的帮助下，我创建了这项工作，尽管我对键盘首先消失有点不满意。

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
    if (textField.tag == 2) {
        if (!geoPoint && !justShowedGeoPointAlert) {
            showingGeoPointAlert = YES;
            UIAlertView* alertView = [[UIAlertView alloc] initWithTitle:@"Alert" message:@"Make sure to geotag this address." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
            [alertView show];
            return NO;
        } else {
            justShowedGeoPointAlert = NO;
        }
    }
    return YES;
}
- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex {
    if (showingGeoPointAlert) {
        justShowedGeoPointAlert = YES;
        showingGeoPointAlert = NO;
        [self.addressTextField becomeFirstResponder];
    }
}

Answer 1

实现 UITextField 的以下委托方法：

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField;

在此方法中显示

警报视图，并在此方法中返回NO，则不会显示键盘。

然后实现以下 UIAlertView 委托方法：

- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex;

在此方法中，显示键盘：

[self.addressTextField becomeFirstResponder];

Answer 2

将UIAlertView的代码移动到- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField，如果返回NO键盘将不会出现

Answer 3

尝试如下操作：

@interface ViewController () <UIAlertViewDelegate, UITextFieldDelegate>
@property (weak, nonatomic) IBOutlet UITextField *textField;
@property (weak, nonatomic) UITextField *selectedTextField;
@end
@implementation ViewController
- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
    if (textField == self.selectedTextField) {
        self.selectedTextField = nil;
        return YES;
    }
    self.selectedTextField = textField;
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Alert" message:@"Text" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [alertView show];
    return NO;
}
- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex {
    [self.selectedTextField becomeFirstResponder];
}
@end