我正在开发一款通用应用程序，应该能够在 iPad 和 iPhone 上运行。 Apple iPad 文档说使用 UI_USER_INTERFACE_IDIOM() 来检查我是否在 iPad 或 iPhone 上运行，但我们的 iPhone 是 3.1.2 并且不会定义 UI_USER_INTERFACE_IDIOM() 。因此，此代码中断：
//iPhone should not be flipped upside down. iPad can have any
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
return YES; //are we on an iPad?
} else {
return interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown;
}
}
在Apple的 SDK 兼容性指南 他们建议执行以下操作来检查该函数是否存在：
//iPhone should not be flipped upside down. iPad can have any
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
if(UI_USER_INTERFACE_IDIOM() != NULL &&
UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
return YES; //are we on an iPad?
} else {
return interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown;
}
}
这有效，但会导致编译器警告：“指针和整数之间的比较。”经过深入研究后，我发现我可以通过以下转换为 (void *) 使编译器警告消失：
//iPhone should not be flipped upside down. iPad can have any
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
if((void *)UI_USER_INTERFACE_IDIOM() != NULL &&
UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
return YES; //are we on an iPad?
} else {
return interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown;
}
}
我的问题是：这里的最后一个代码块可以/可接受/标准做法吗？我找不到其他人通过快速搜索做类似的事情，这让我想知道我是否错过了陷阱或类似的事情。
谢谢。
I am working on a universal app that should be able to run on iPad and iPhone. The Apple iPad docs say to use UI_USER_INTERFACE_IDIOM() to check if I am running on iPad or iPhone, but our iPhone is 3.1.2 and will not have UI_USER_INTERFACE_IDIOM() defined. As such, this code breaks:
//iPhone should not be flipped upside down. iPad can have any
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
return YES; //are we on an iPad?
} else {
return interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown;
}
}
In Apple's SDK Compatibility Guide they suggest doing the following to check if the function exists:
//iPhone should not be flipped upside down. iPad can have any
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
if(UI_USER_INTERFACE_IDIOM() != NULL &&
UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
return YES; //are we on an iPad?
} else {
return interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown;
}
}
This works, but results in the compiler warning: "Comparison between pointer and integer." After digging around I figured out that I can make the compiler warning disappear with the following cast to (void *):
//iPhone should not be flipped upside down. iPad can have any
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
if((void *)UI_USER_INTERFACE_IDIOM() != NULL &&
UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
return YES; //are we on an iPad?
} else {
return interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown;
}
}
My question is this: Is the last code block here okay/acceptable/standard practice? I couldn't find anyone else doing something like this with quick searching which makes me wonder if I missed a gotcha or something similar.
Thanks.
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评论（1）
您需要根据 3.2 SDK 构建 iPad 应用程序。因此，它将正确构建，并且 UI_USER_INTERFACE_IDIOM() 宏仍然有效。如果您想知道如何/为什么，请在文档中查找它 - 它是一个 #define，它将被编译器理解并编译成可以在 3.1（等）上正确运行的代码。
You need to build apps for iPad against the 3.2 SDK. As such it will build correctly, and the UI_USER_INTERFACE_IDIOM() macro will still work. If you want to know how/why, look it up in the docs - it is a #define, which will be understood by the compiler and compile into code that will run correctly on 3.1 (etc).