提示框的綜合使用--UIAlertViewController

UIAlertViewController貌似把UIAlertView和UIActionSheet二合一了

- (void)showOkayCancelAlert {
    NSString *title = NSLocalizedString(@"A Short Title Is Best", nil);
    NSString *message = NSLocalizedString(@"A message should be a short, complete sentence.", nil);
    NSString *cancelButtonTitle = NSLocalizedString(@"Cancel", nil);
    NSString *otherButtonTitle = NSLocalizedString(@"OK", nil);

    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:title message:message preferredStyle:UIAlertControllerStyleAlert];
    
    // Create the actions.
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:cancelButtonTitle style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
        NSLog(@"The \"Okay/Cancel\" alert's cancel action occured.");
    }];
    
    UIAlertAction *otherAction = [UIAlertAction actionWithTitle:otherButtonTitle style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
        NSLog(@"The \"Okay/Cancel\" alert's other action occured.");
    }];
    
    // Add the actions.
    [alertController addAction:cancelAction];
    [alertController addAction:otherAction];
    
    [self presentViewController:alertController animated:YES completion:nil];
}

這是最普通的一個alertcontroller，一個取消按鈕，一個確定按鈕。

新的alertcontroller，其初始化方法也不一樣了，按鈕響應方法綁定使用了block方式，有利有弊。需要注意的是不要因為block導致了引用循環，記得使用__weak，尤其是使用到self。

上面的界面如下：

如果UIAlertAction *otherAction這種otherAction多幾個的話，它會自動排列成如下：

另外，很多時候，我們需要在alertcontroller中添加一個輸入框，例如輸入密碼：

這時候可以添加如下代碼：

 [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
        // 可以在這里對textfield進行定制，例如改變背景色
        textField.backgroundColor = [UIColor orangeColor];
    }];

而改變背景色會這樣：

完整的密碼輸入：

- (void)showSecureTextEntryAlert {
    NSString *title = NSLocalizedString(@"A Short Title Is Best", nil);
    NSString *message = NSLocalizedString(@"A message should be a short, complete sentence.", nil);
    NSString *cancelButtonTitle = NSLocalizedString(@"Cancel", nil);
    NSString *otherButtonTitle = NSLocalizedString(@"OK", nil);

    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:title message:message preferredStyle:UIAlertControllerStyleAlert];
    
    // Add the text field for the secure text entry.
    [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
        // Listen for changes to the text field's text so that we can toggle the current
        // action's enabled property based on whether the user has entered a sufficiently
        // secure entry.
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleTextFieldTextDidChangeNotification:) name:UITextFieldTextDidChangeNotification object:textField];

        textField.secureTextEntry = YES;
    }];

    // Create the actions.
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:cancelButtonTitle style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
        NSLog(@"The \"Secure Text Entry\" alert's cancel action occured.");

        // Stop listening for text changed notifications.
        [[NSNotificationCenter defaultCenter] removeObserver:self name:UITextFieldTextDidChangeNotification object:alertController.textFields.firstObject];
    }];

    UIAlertAction *otherAction = [UIAlertAction actionWithTitle:otherButtonTitle style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
        NSLog(@"The \"Secure Text Entry\" alert's other action occured.");

        // Stop listening for text changed notifications.
        [[NSNotificationCenter defaultCenter] removeObserver:self name:UITextFieldTextDidChangeNotification object:alertController.textFields.firstObject];
    }];
    
    // The text field initially has no text in the text field, so we'll disable it.
    otherAction.enabled = NO;

    // Hold onto the secure text alert action to toggle the enabled/disabled state when the text changed.
    self.secureTextAlertAction = otherAction;

    // Add the actions.
    [alertController addAction:cancelAction];
    [alertController addAction:otherAction];
    
    [self presentViewController:alertController animated:YES completion:nil];
}

注意四點：

1.添加通知，監聽textfield內容的改變：

// Add the text field for the secure text entry.
    [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
        // Listen for changes to the text field's text so that we can toggle the current
        // action's enabled property based on whether the user has entered a sufficiently
        // secure entry.
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleTextFieldTextDidChangeNotification:) name:UITextFieldTextDidChangeNotification object:textField];

        textField.secureTextEntry = YES;
    }];

2.初始化時候，禁用“ok”按鈕：

otherAction.enabled = NO;

self.secureTextAlertAction = otherAction;//定義一個全局變量來存儲

3.當輸入超過5個字符時候，使self.secureTextAlertAction ＝ YES：

- (void)handleTextFieldTextDidChangeNotification:(NSNotification *)notification {
    UITextField *textField = notification.object;

    // Enforce a minimum length of >= 5 characters for secure text alerts.
    self.secureTextAlertAction.enabled = textField.text.length >= 5;
}

4.在“OK”action中去掉通知：

UIAlertAction *otherAction = [UIAlertAction actionWithTitle:otherButtonTitle style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
        NSLog(@"The \"Secure Text Entry\" alert's other action occured.");

        // Stop listening for text changed notifications.
        [[NSNotificationCenter defaultCenter] removeObserver:self name:UITextFieldTextDidChangeNotification object:alertController.textFields.firstObject];
    }];

 

最后是以前經常是alertview與actionsheet結合使用，這里同樣也有：

- (void)showOkayCancelActionSheet {
    NSString *cancelButtonTitle = NSLocalizedString(@"Cancel", nil);
    NSString *destructiveButtonTitle = NSLocalizedString(@"OK", nil);
    
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
    
    // Create the actions.
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:cancelButtonTitle style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
        NSLog(@"The \"Okay/Cancel\" alert action sheet's cancel action occured.");
    }];
    
    UIAlertAction *destructiveAction = [UIAlertAction actionWithTitle:destructiveButtonTitle style:UIAlertActionStyleDestructive handler:^(UIAlertAction *action) {
        NSLog(@"The \"Okay/Cancel\" alert action sheet's destructive action occured.");
    }];
    
    // Add the actions.
    [alertController addAction:cancelAction];
    [alertController addAction:destructiveAction];
    
    [self presentViewController:alertController animated:YES completion:nil];
}

在底部顯示如下：

 

好了，至此，基本就知道這個新的controller到底是怎樣使用了