IOS - 递归函数离开内存分配

Question

我有一个测试应用程序，我在这个应用程序中拥有的是通过 PHP 脚本进行的调用，一旦数据返回，递归调用就会一次又一次地调用 PHP 脚本，依此类推:

发生的事情是每次 [Self recusiveForumActivity];被调用时，我分配了 300kb 的内存，并且在调用此递归方法时内存使用量不断攀升。如果我删除该方法，内存使用量将保持稳定。我怎样才能克服这个问题，以便在每次调用递归方法时都不会丢失内存分配？

这是代码:

//
        //  ViewController.m
        //  Test
        //
        //  Created by trikam patel on 30/06/2015.
        //  Copyright (c) 2015 trikam patel. All rights reserved.
        //

        #import "ViewController.h"

        @interface ViewController ()

        @end

        @implementation ViewController


        -(NSString*)setupPhpCall:(NSString*)requestString :(NSString*)sciptPage{

            //NSURLCache *sharedCache = [[NSURLCache alloc] initWithMemoryCapacity:0 diskCapacity:0 diskPath:0];
            //[NSURLCache setSharedURLCache:sharedCache];


            NSHTTPURLResponse *urlresponse = nil;
            NSError *error = nil;
            NSString *response = @"";
            NSData *myRequestData = nil;
            NSMutableURLRequest *request = nil;
            NSData *returnData = nil;

            myRequestData = [NSData dataWithBytes: [requestString UTF8String] length: [requestString length]];

            //Create your request string with parameter name as defined in PHP file
            request = [[NSMutableURLRequest alloc] initWithURL: [NSURL URLWithString: [NSString stringWithFormat: @"http://www.hugt.co.uk/%@", sciptPage]]];
            // set Request Type
            [request setHTTPMethod: @"POST"];
            // Set content-type
            [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"content-type"];
            // Set Request Body
            [request setHTTPBody: myRequestData];
            // Now send a request and get Response
            //NSHTTPURLResponse* urlResponse = nil;
            //NSError *error = nil;

            //if(tmpArray.count == 0){
            returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:&urlresponse error: &error];
            response = [[NSString alloc] initWithBytes:[returnData bytes] length:[returnData length] encoding:NSUTF8StringEncoding];
            //}
            // Log Response
            urlresponse = nil;
            error = nil;
            myRequestData = nil;
            request = nil;
            returnData = nil;

            //NSLog(@"%@",response);/****/
            //[sharedCache removeAllCachedResponses];
            if(response != nil){

            return response;
            }

            return nil;
        }

        -(void)recurseForumActivity{
            dispatch_queue_t concurrentQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

            dispatch_async(concurrentQueue, ^{


            __block NSString *myRequestStringForum = [NSString stringWithFormat:@"lastDate=%@&threadTitle=%@&threadCountry=%@&threadCategory=%@&threadSubCategory=%@&getData=0",@"",@"", @"", @"", @""];
            __block NSString *responseForum = [self setupPhpCall:myRequestStringForum :@"getThreadRecurse.php"];


            dispatch_async(dispatch_get_main_queue(), ^{

                dispatch_queue_t concurrentQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

                dispatch_async(concurrentQueue, ^{

                dispatch_async(dispatch_get_main_queue(), ^{
                    [NSThread sleepForTimeInterval:2.0f];
                    responseForum = @"";
                    myRequestStringForum = @"";
                    [self recurseForumActivity];
                });
                });

            });

            });

        }

        - (void)viewDidLoad {
            [super viewDidLoad];
            [self recurseForumActivity];
            // Do any additional setup after loading the view, typically from a nib.
        }

        - (void)didReceiveMemoryWarning {
            [super didReceiveMemoryWarning];
            // Dispose of any resources that can be recreated.
        }

        @end

Answer 1

尝试使用 [object performSelector:method] 而不是递归调用。递归函数必须始终具有基本/退出条件，而您的代码没有任何此类条件。所以你不能在这里进行任何递归调用。

- (void)recurseForumActivity{
    dispatch_queue_t concurrentQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    dispatch_async(concurrentQueue, ^{

        __block NSString *myRequestStringForum = [NSString stringWithFormat:@"lastDate=%@&threadTitle=%@&threadCountry=%@&threadCategory=%@&threadSubCategory=%@&getData=0",@"",@"", @"", @"", @""];
        __block NSString *responseForum = [self setupPhpCall:myRequestStringForum :@"getThreadRecurse.php"];

        YourClass * __weak weakSelf = self;

        dispatch_async(dispatch_get_main_queue(), ^{

            dispatch_queue_t concurrentQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

            dispatch_async(concurrentQueue, ^{

                dispatch_async(dispatch_get_main_queue(), ^{
                    responseForum = @"";
                    myRequestStringForum = @"";
                    [weakSelf performSelector:@selector(recurseForumActivity) withObject:nil afterDelay:2.0f];
                });
            });

        });

    });
}