当我运行iPhone应用程序时，它只显示一个白色窗口，但当我按下home按钮时，它会显示输出内容'；怎么了？

我的代码是

window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
window.backgroundColor = [UIColor blackColor];  
CGRect rect = CGRectMake(0,0,320,480);

view = [ [ UIView alloc ] initWithFrame:rect ];
view.backgroundColor = [UIColor blueColor]; 
[window addSubview:view];

// Override point for customization after application launch
[window makeKeyAndVisible];

删除以下内容：

window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];