iOS UIAlertView弹框

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];    // Override point for customization after application launch.    self.window.backgroundColor = [UIColor whiteColor];    [self.window makeKeyAndVisible];            UIButton *btn1=[UIButton buttonWithType:UIButtonTypeRoundedRect];    [btn1 setTitle:@"Alert" forState:UIControlStateNormal];    btn1.frame=CGRectMake(10, 100, 100, 40);    [btn1 addTarget:self action:@selector(AlertViewShow) forControlEvents:UIControlEventTouchUpInside];    [self.window addSubview:btn1];            UIButton *btn2=[UIButton buttonWithType:UIButtonTypeRoundedRect];    [btn2 setTitle:@"ActionSheet" forState:UIControlStateNormal];    btn2.frame=CGRectMake(210, 100, 100, 40);    [btn2 addTarget:self action:@selector(ActionSheetShow) forControlEvents:UIControlEventTouchUpInside];    [self.window addSubview:btn2];                return YES;}-(void)AlertViewShow{    UIAlertView *pAlert=[[UIAlertView alloc]initWithTitle:@"警告" message:@"this is alertView" delegate:self cancelButtonTitle:@"cancel" otherButtonTitles:@"sure", nil];    [pAlert show];    [pAlert release];}-(void)ActionSheetShow{    UIActionSheet *pSheet=[[UIActionSheet alloc]initWithTitle:@"ActionView" delegate:self cancelButtonTitle:@"cancel" destructiveButtonTitle:@"确定" otherButtonTitles:@"第一页",@"第二页", nil];        [pSheet showInView:self.window];        [pSheet release];}