Question

我的拆分视图控制器代码：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    LeftViewController *hvc = [[[LeftViewController alloc] initWithNibName:nil bundle:nil] autorelease];    
    DetailViewController *dvc = [[[DetailViewController alloc] initWithNibName:nil bundle:nil] autorelease];
    UINavigationController *rootNav = [[[UINavigationController alloc] initWithRootViewController:hvc] autorelease];
    UINavigationController *detailNav = [[[UINavigationController alloc] initWithRootViewController:dvc] autorelease];
    UISplitViewController *svc= [[[UISplitViewController alloc] init] autorelease];
    [svc setViewControllers:[NSArray arrayWithObjects:rootNav, detailNav, nil]];
    svc.delegate = dvc;
    [window setRootViewController:svc];
    [self.window makeKeyAndVisible];
    return YES;
}

DetailViewController.m和LeftViewController.m都包含

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    NSLog(@"should rotate asked to detailviewcontroller");
    return YES;
}

在iPad模拟器上，当应用程序刚刚启动时，我可以看到shouldAutorotateToInterfaceOrientation的这么多来电

should rotate asked to detailviewcontroller
should rotate asked to leftviewcontroller
should rotate asked to leftviewcontroller
should rotate asked to detailviewcontroller
...
should rotate asked to leftviewcontroller   // these two lines
should rotate asked to detailviewcontroller // are repeated 13 times
...
should rotate asked to leftviewcontroller
should rotate asked to detailviewcontroller

这背后的原因是什么？我必须提到我不是在改变模拟器的方向

Answer 1

shouldAutorotateToInterfaceOrientation用于检查您的视图是否支持特定方向。

这并不一定意味着您的设备正在移动/正在旋转。

您不应该担心导致外部实体多次查询您的视图控制器的实现细节，只需为您的视图返回适当的值。

如果您对检测设备轮换感兴趣，可能会决定依赖UIDeviceOrientationDidChangeNotification。

shouldAutorotateToInterfaceOrientation被多次调用 - 这是正常的吗？

1 个答案: