iOS 4.2 如何在方向改变时显示不同的图像？

Question

iOS4.2 当我的应用程序启动时，我会显示一个在我的 web 视图加载之前可见的图像。在 webview 加载后，该图像被设置为隐藏。如何执行以下操作： 如果是纵向，则显示 DefaultPortrait.png 如果是横向则显示 DefaultLandscape.png？

如果设备是纵向的，则显示

self.view.backgroundColor = [UIColor blackColor];
CGRect myImageRect = CGRectMake(0.0f, 0.0f, 320.0f, 480.0f);
myImage = [[UIImageView alloc] initWithFrame:myImageRect];
[myImage setImage:[UIImage imageNamed:@"Default2.png"]];
myImage.opaque = YES; // explicitly opaque for performance
[self.view addSubview:myImage];
[myImage release];

或

如果设备是横向的，则显示

CGRect myImageRect = CGRectMake(0.0f, 0.0f, 480f, 320.0f);
myImage = [[UIImageView alloc] initWithFrame:myImageRect];
[myImage setImage:[UIImage imageNamed:@"Default2L.png"]];
myImage.opaque = YES; // explicitly opaque for performance
[self.view addSubview:myImage];
[myImage release];

Answer 1

您可以使用didRotateFromInterfaceOrientation 来实现您的代码。现在，当方向将从纵向更改时，实现您想要在设备处于横向模式时显示的代码，反之亦然。希望它能解决你的问题。

    - (void) didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation{
    if ((fromInterfaceOrientation == UIInterfaceOrientationPortrait) || (fromInterfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)) {

        // your method for landscape..

    }
    if ((fromInterfaceOrientation == UIInterfaceOrientationLandscapeRight) || (fromInterfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)) {

        //your method for portrait
    }
}

Answer 2

您可以在开始时使用它来获取当前方向：

   UIInterfaceOrientation currentOrientation = [[UIApplication sharedApplication] statusBarOrientation] 

然后使用这个：

 if ((currentOrientation == UIInterfaceOrientationPortrait) || (currentOrientation == UIInterfaceOrientationPortraitUpsideDown)) {
self.view.backgroundColor = [UIColor blackColor];
CGRect myImageRect = CGRectMake(0.0f, 0.0f, 320.0f, 480.0f);
myImage = [[UIImageView alloc] initWithFrame:myImageRect];
[myImage setImage:[UIImage imageNamed:@"Default2.png"]];
myImage.opaque = YES; // explicitly opaque for performance
[self.view addSubview:myImage];
[myImage release];

    }
   else if ((currentOrientation == UIInterfaceOrientationLandscapeRight) || (currentOrientation == UIInterfaceOrientationLandscapeLeft)) {
self.view.backgroundColor = [UIColor blackColor];
CGRect myImageRect = CGRectMake(0.0f, 0.0f, 320.0f, 480.0f);
myImage = [[UIImageView alloc] initWithFrame:myImageRect];
[myImage setImage:[UIImage imageNamed:@"Default2.png"]];
myImage.opaque = YES; // explicitly opaque for performance
[self.view addSubview:myImage];
[myImage release];
}

Answer 3

如果您想在两种模式下显示相同的图像，那么首先您在应用程序委托文件中声明一个布尔类型变量并在应用程序委托 .m 文件中定义。 IF 纵向模式变量为 true，横向则为 false。现在在

_(void)viewDidLoad{
              if (Boolean variable == TRUE ){
                                         //display portrait mode }
                 else 
                      //display landscape mode

}