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，我会显示一个可见的图像，直到我的 webview 加载为止。 Web 视图加载后，该图像将设置为隐藏。如何执行以下操作： 如果是纵向，则显示 DefaultPortrait.png 如果横向，则显示 DefaultLandscape.png？

如果设备是纵向则显示

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];

，或者

如果设备是横向则显示

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。希望它能解决您的问题。

    - (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] 

然后使用它：

 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。如果是纵向模式，则该变量为 true；如果是横向模式，则该变量为 false。现在在

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

}