- (void)didReceiveMemoryWarning//内存警告
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
    
    NSLog(@"内存快爆了");

         //判断是否加载过 或者是否正在屏幕上显示
    if([self isViewLoaded]==YES &&self.view.window==nil){
    
        //将跟视图销毁
        self.view=nil;
    }
}