iOS8.0 之後UIAlertView和UIActionSheet的創建方式的新變化
最近已經換了Xcode 6.1,開始適配iOS 8.0以上版本了,在iOS 8以前,我們創建一個警告視圖(UIAlertView),通常是這樣的
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Title" message:@"Message" delegate:self cancelButtonTitle:@"取消" otherButtonTitles:@"確定", nil]; [alertView show];
運行後,如圖所示:
通過UIAlertViewDelegate 中的
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex;來響應按鈕事件
創建一個選擇按鈕項( UIActionSheet),通常是這樣的:
UIActionSheet *actioSheet = [[UIActionSheet alloc] initWithTitle:@"Title" delegate:self cancelButtonTitle:@"Cancel" destructiveButtonTitle:@"Destructive" otherButtonTitles:@"otherButton", nil]; [actioSheet showInView:self.view];
運行後如圖所示:
通過UIActionSheetDelegate中的
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex;響應按鈕事件
但是在Xcode 6.1 iOS 8.0 的環境下,創建這兩個控件會出現這樣的提示
( 重要:UIAlerView 在iOS8中已棄用,同時UIAlertViewDeleagte也過時。在iOS8以後用UIAlertController的preferredStyle類型中的UIAlertControllerStyleAlert來創建和管理警告)
雖然蘋果申明UIAlertView已經被被棄用,但是我們創建UIAlertView在iOS 8下運行並沒有給出任何警告……
那我們就一起來看一下這個UIAlertController 是怎麼用的,下面就是UIAlertController.h的全部內容
#import <UIKit/UIViewController.h> typedef NS_ENUM(NSInteger, UIAlertActionStyle) { UIAlertActionStyleDefault = 0, UIAlertActionStyleCancel, UIAlertActionStyleDestructive } NS_ENUM_AVAILABLE_IOS(8_0); typedef NS_ENUM(NSInteger, UIAlertControllerStyle) { UIAlertControllerStyleActionSheet = 0, UIAlertControllerStyleAlert } NS_ENUM_AVAILABLE_IOS(8_0); NS_CLASS_AVAILABLE_IOS(8_0) @interface UIAlertAction : NSObject <NSCopying> + (instancetype)actionWithTitle:(NSString *)title style:(UIAlertActionStyle)style handler:(void (^)(UIAlertAction *action))handler; @property (nonatomic, readonly) NSString *title; @property (nonatomic, readonly) UIAlertActionStyle style; @property (nonatomic, getter=isEnabled) BOOL enabled; @end NS_CLASS_AVAILABLE_IOS(8_0) @interface UIAlertController : UIViewController + (instancetype)alertControllerWithTitle:(NSString *)title message:(NSString *)message preferredStyle:(UIAlertControllerStyle)preferredStyle; - (void)addAction:(UIAlertAction *)action; @property (nonatomic, readonly) NSArray *actions; - (void)addTextFieldWithConfigurationHandler:(void (^)(UITextField *textField))configurationHandler; @property (nonatomic, readonly) NSArray *textFields; @property (nonatomic, copy) NSString *title; @property (nonatomic, copy) NSString *message; @property (nonatomic, readonly) UIAlertControllerStyle preferredStyle; @end
使用 + 方法來創建一個UIAlertController
+ (instancetype)alertControllerWithTitle:(NSString *)title message:(NSString *)message preferredStyle:(UIAlertControllerStyle)preferredStyle;
UIAlertControllerStyle枚舉內容:
typedef NS_ENUM(NSInteger, UIAlertControllerStyle) {
UIAlertControllerStyleActionSheet = 0,
UIAlertControllerStyleAlert
}
顯然可以通過這個方法同時來創建一個Alert 或者ActionSheet
沒有了按鈕標題參數,取而代之的是一個UIAction類來管理按鈕選項,同樣通過一個+方法來創建
+ (instancetype)actionWithTitle:(NSString *)title style:(UIAlertActionStyle)style handler:(void (^)(UIAlertAction *action))handler;
通過一個Block回調來處理按鈕響應事件,這果然很棒!!
所以呢,在iOS 8後,創建一個AlertView,已經變成這樣了(官方源代碼):
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];運行後如圖所示:
創建一個ActionSheet方法類似:
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];