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爲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) { // 可以在這裏對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]; }];
最後是以前經常是alertview與actionsheet結合使用,這裏同樣也有:
- (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。