查看崩溃日志

在遇到客户端crash的时候，如果没有崩溃日志或者重现的时候你不是连着调试，很难解决问题
我们可以把崩溃日志写入到本地文件方便调试

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{

    [self redirectNSlogToDocumentFolder];

}


- (void)redirectNSlogToDocumentFolder
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentDirectory = [paths objectAtIndex:0];
    NSString *fileName = [NSString stringWithFormat:@"dr.log"];// 注意不是NSData!
    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);
}