警告对话框&等待提示器

@synthesize alertView = _alertView;
@synthesize activityIndicator = _activityIndicator;

- (void)viewDidLoad {
    [super viewDidLoad];

    for(int i=0;i<2;i++){
        UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
        
        btn.frame = CGRectMake(100, 100+i*100, 100, 40);
        
        if(i==0)
        {
            [btn setTitle:(@"警告提示框") forState:UIControlStateNormal];
        }
        else if(i==1)
        {
            [btn setTitle:(@"等待指示器") forState:UIControlStateNormal];
        }
        btn.tag = 101 + i;
        
        [btn addTarget:self action:@selector(pressBtn:) forControlEvents:UIControlEventTouchUpInside];
        
        [self.view addSubview:btn];
    }

}

-(void) pressBtn:(UIButton *) btn
{
    if(btn.tag == 101)
    {
        _alertView = [[UIAlertView alloc] initWithTitle:@"警告" message:@"您的电量过低" delegate:self cancelButtonTitle:@"取消" otherButtonTitles:@"朕知道了",@"11",@"22", nil];
        [_alertView show];
    }else if(btn.tag == 102)
    {
        //宽度高度不可变
        _activityIndicator = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(100, 500,80,80)];
        
        _activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge;
        
        self.view.backgroundColor = [UIColor blackColor];
        
        [self.view addSubview:_activityIndicator];
        
        [_activityIndicator startAnimating];
    }
   
    
}
//当点击对话框的按钮时，调用此函数
-(void) alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    NSLog(@"index = %ld
",buttonIndex);
    
}

//对话框即将消息，此函数被调用

-(void) alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex
{
    NSLog(@"will dismiss");
    
}


-(void) alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
{
    NSLog(@"have already dismissed");
    
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


@end

@interface ViewController : UIViewController<UIAlertViewDelegate>
{
    //定义一个警告提示框
    UIAlertView* _alertView;
    //定义一个等待提示对象,转圈
    UIActivityIndicatorView* _activityIndicator;
    
}

//属性定义
@property(retain,nonatomic) UIAlertView* alertView;

@property(retain,nonatomic) UIActivityIndicatorView* activityIndicator;