自从在 iOS 8 上测试我的应用程序后,我发现围绕 View Controller 初始化和呈现的工作非常慢。
我曾经在 iOS 6 和 7 上使用过类似的代码:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
....
[self.window setRootViewController:_rootController];
[self.window makeKeyAndVisible];
// Conditions
if (#first launch condition#) {
// quite small controller containing Welcome showcase
WelcomeViewController *w = ....
[_rootViewController presentViewController:w animated:NO];
}
else if (#last opened item condition#) {
// pretty big container, root view controller contains
// a grid view which opens Item detail container the same way
ItemDetailController *item = ....
[_rootViewController presentViewController:item animated:NO];
}
}
在 iOS 8 中,这变成了一个非常缓慢的 hell 。 Root View Controller 现在显示 0.5-1 秒,然后立即重新绘制屏幕。此外,呈现的缓慢开始导致 Unbalanced calls to begin/end appearance transitions _rootViewController
警告。
最初的快速提示是通过调用另一个函数来移动两个条件,并以零延迟调用它,以便在下一个主运行循环中处理它:
[self performSelector:@selector(postAppFinishedPresentation) withObject:nil afterDelay:0];
或类似的东西。这解决了不平衡的调用问题,但视觉差距(rootviewcontroller、差距、呈现的差距)变得(显然)更大。
当您调用通常的东西时,演示的缓慢也很明显:
// Example: Delegate caught finished Sign In dialog,
// dismiss it and instantly switch to Profile controller
-(void)signInViewControllerDidFinishedSuccessfully
{
[self dismissViewControllerAnimated:NO completion:^{
UserProfileViewController *userProfile = ...
[self presentViewController:userProfile animated:NO];
}];
}
这应该是一段完全公平的代码,它曾经在 iOS 7 上执行直接过渡,而无需父 View Controller 的可见轻弹。现在,同样的事情 – 父 View Controller 在过渡期间轻弹,即使它都在没有动画的情况下处理。
p>有人将此视为问题吗?任何解决方案?我很乐意解决这个问题,而无需为我需要完美传输的每件事使用 UIWindow
做一些有趣的魔术。
最佳答案
我不确定要求仅限于拥有 Root View Controller 并在那里呈现任何内容。
但根据您的代码,它有欢迎 View Controller 的东西,我认为在这种情况下,这个逻辑更有用。
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
// Conditions
if (#first launch condition#) {
// quite small controller containing Welcome showcase
WelcomeViewController *w = ....
//It can be navigation or tab bar controller which have "w" as rootviewcontroller
[self.window setRootViewController:w];
}
else if (#last opened item condition#) {
// pretty big container, root view controller contains
// a grid view which opens Item detail container the same way
ItemDetailController *item = ....
//It can be navigation or tab bar controller which have "item" as rootviewcontroller
[self.window setRootViewController:item];
}
[self.window makeKeyAndVisible];
}
关于iOS 8 – 在设置关键窗口或关闭并立即呈现另一个 View Controller 后快速呈现 View Controller 时出现故障,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/25977717/