我们如何在 Xcode 中创建整数类型的全局变量
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How can we make a global variable of integer type in Xcode
提问by Amit Raj
How can I declare a global variable in Xcode and its data type should be integer and accessible by every class.
我如何在 Xcode 中声明一个全局变量，它的数据类型应该是整数并且每个类都可以访问。
回答by djromero
In some very special cases a truly global variable can simplify things. I don't think you researched the problem exhaustively, but here is my answer anyway, a simple case:
在一些非常特殊的情况下，一个真正的全局变量可以简化事情。我认为您没有详尽地研究这个问题，但无论如何，这是我的答案，一个简单的案例：
// Globals.h
#ifndef Globals_h
#define Globals_h
extern NSInteger globalVariable;
#endif
// main.m
NSInteger globalVariable;
int main(int argc, char *argv[])
{
globalVariable = <# initial value #>;
...
}
// Prefix.pch
#ifdef __OBJC__
#import
#import <Foundation/Foundation.h>
#import "Globals.h"
#endif
Now, you can use globalVariableanywhere in your code, you don't even need to include the header file.
现在，您可以globalVariable在代码中的任何位置使用，甚至不需要包含头文件。
Warning: things are slightly complex if you need thread safety or a different variable type.
警告：如果您需要线程安全或不同的变量类型，事情会稍微复杂一些。
回答by Alex Moskalev
You can use global variable in you AppDelegate :
您可以在 AppDelegate 中使用全局变量：
@interface myAppDelegate : NSObject <UIApplicationDelegate> {
MyDBManager *myDBManager;
}
@property (nonatomic, retain) MyDBManager *myDBManager;
@end
@interface AnyOtherClass : UITableViewController {
MyDBManager *myDBManager;
NSObject *otherVar;
}
@property (nonatomic,retain) MyDBManager *myDBManager;
@property (nonatomic,retain) NSObject *otherVar;
@end
//getting the data from "global" myDBManager and putting it into local var of AnyOtherClass
- (void)viewWillAppear:(BOOL)animated {
//get the myDBManager global Object
MyAppDelegate *mainDelegate = (MyAppDelegate *)[[UIApplication sharedApplication]delegate];
myDBManager = mainDelegate.myDBManager;
}
- (void)dealloc {
[otherVar release];
//[dancesDBManager release]; DO NOT RELEASE THIS SINCE ITS USED AS A GLOBAL VARIABLE!
[super dealloc];
}
Hope it will help
希望它会有所帮助
