iOS8中提示框的使用UIAlertController(UIAlertView和UIActionSheet變形平板)

標籤：

iOS8推出了幾個新的“controller”，主要是把類似之前的UIAlertView變成了UIAlertController，這不經意的改變，貌似把我之前理解的“controller”一下子推翻了～但是也無所謂，有新東西不怕，學會使用了就行。接下來會探討一下這些個新的Controller。

 

- (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，按鈕回應程式法綁定使用了block方式，有利有弊。需要注意的是不要因為block導致了引用迴圈，記得使用__weak，尤其是使用到self。

上面的介面如下：

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

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) {        // 可以在這裡對textfield進行定製，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;//定義一個全域變數來儲存

3.當輸入超過5個字元時候，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];    }];

 

最後是以前經常是alertview與actionsheet結合使用，這裡同樣也有：

- (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。

iOS8中提示框的使用UIAlertController(UIAlertView和UIActionSheet變形平板)