objective-c - 如何为特定视图的导航栏设置自定义背景图像

Question

我在应用程序 delegate.m 中使用此代码：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:  (NSDictionary *)launchOptions {
   // Rename "specialNavBar.png" to the file name of your specific navigation bar    background image.
    UIImage *special = [UIImage imageNamed:@"movBar.png"];

     // Rename "SpecialViewController" to the class name that you want to have a different navigation bar for.
    [[UINavigationBar appearanceWhenContainedIn:[MovableViewController class], nil] setBackgroundImage:special
                                                                                     forBarMetrics:UIBarMetricsDefault];

// Override point for customization after application launch.
return YES;

}

APP崩溃并给我这个错误信息：

由于未捕获的异常“ NSUnknownKeyException”而终止应用程序，原因：“ [<MovableViewController 0xa17eb90> setValue:forUndefinedKey:]：此类不符合键的键值编码navBar。” * First throw call stack: (0x1d11012 0x11f3e7e 0x1d99fb1 0xc9fe41 0xc215f8 0xc210e7 0xc4bb58 0x355019 0x1207663 0x1d0c45a 0x353b1c 0x2187e7 0x218dc8 0x218ff8 0x219232 0x1683d5 0x16876f 0x168905 0x171917 0x13596c 0x13694b 0x147cb5 0x148beb 0x13a698 0x1f4adf9 0x1f4aad0 0x1c86bf5 0x1c86962 0x1cb7bb6 0x1cb6f44 0x1cb6e1b 0x13617a 0x137ffc 0x276d 0x2695) libc++abi.dylib:终止称为抛出异常

Answer 1

您可以像这样在导航栏中添加自定义图像。

_window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
UIImage *special = [UIImage imageNamed:@"movBar.png"];
[_window.rootViewController.navigationController.navigationBar setBackgroundImage:special forBarMetrics:UIBarMetricsDefault];

Answer 2

在要更改其背景的视图控制器中调用-setBackgroundImage:您的。UINavigationBar然后，在-viewWillDisappear:方法中，将其设置回原始图像。