1.在AppDelegate.m中添加下代码块:

- (void)redirectNSlogToDocumentFolder

{

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *documentDirectory = [paths objectAtIndex:0];

NSString *fileName = [NSString stringWithFormat:@"MyLog.txt"];

NSString *logFilePath = [documentDirectory stringByAppendingPathComponent:fileName];

// 先删除已经存在的文件

NSFileManager *defaultManager = [NSFileManager defaultManager];

[defaultManager removeItemAtPath:logFilePath error:nil];

// 将log输入到文件

freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a+", stdout);

freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a+", stderr);

}

2.在didFinishLaunchingWithOptions中调用 :

[self redirectNSlogToDocumentFolder];

运行你的app，在沙盒Documents下即可找到 MyLog.txt 。将其导出 分析即可