在 Swift 中捕获 NSException [英] Catching NSException in Swift

问题描述

Swift 中的以下代码引发 NSInvalidArgumentException 异常:

The following code in Swift raises NSInvalidArgumentException exception:

task = NSTask()
task.launchPath = "/SomeWrongPath"
task.launch()

如何捕捉异常?据我了解，Swift 中的 try/catch 是针对 Swift 中引发的错误，而不是针对从 NSTask(我猜是用 ObjC 编写的)之类的对象引发的 NSExceptions.我是 Swift 的新手，所以可能我遗漏了一些明显的东西......

How can I catch the exception? As I understand, try/catch in Swift is for errors thrown within Swift, not for NSExceptions raised from objects like NSTask (which I guess is written in ObjC). I'm new to Swift so may be I'm missing something obvious...

编辑:这里是错误的雷达(特别是 NSTask):openradar.appspot.com/22837476

Edit: here's a radar for the bug (specifically for NSTask): openradar.appspot.com/22837476

推荐答案

这里有一些代码，将 NSExceptions 转换为 Swift 2 错误.

Here is some code, that converts NSExceptions to Swift 2 errors.

现在你可以使用

do {
    try ObjC.catchException {

       /* calls that might throw an NSException */
    }
}
catch {
    print("An error ocurred: (error)")
}

ObjC.h:

#import <Foundation/Foundation.h>

@interface ObjC : NSObject

+ (BOOL)catchException:(void(^)(void))tryBlock error:(__autoreleasing NSError **)error;

@end

ObjC.m

#import "ObjC.h"

@implementation ObjC 

+ (BOOL)catchException:(void(^)(void))tryBlock error:(__autoreleasing NSError **)error {
    @try {
        tryBlock();
        return YES;
    }
    @catch (NSException *exception) {
        *error = [[NSError alloc] initWithDomain:exception.name code:0 userInfo:exception.userInfo];
        return NO;
    }
}

@end

不要忘记将其添加到您的*-Bridging-Header.h"中:

Don't forget to add this to your "*-Bridging-Header.h":

#import "ObjC.h"

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