当网络连接不佳时，iOS 应用程序在启动时会挂起一段时间
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【中文标题】当网络连接不佳时，iOS 应用程序在启动时会挂起一段时间【英文标题】：iOS app hang for a while at startup when network connection is poor 【发布时间】：2015-01-21 12:19:01 【问题描述】：我有一个很大的问题，我正在地铁中测试我的应用程序，当我在一个超级糟糕的覆盖站中时，我的应用程序在启动应用程序的第一个屏幕上冻结了一段时间（比如 30 秒或 1 分钟） cero，然后一切都开始像魅力一样工作。
我有 2 个函数负责在我的 WS 中查找信息（响应是 JSON），并且我已将此 NSURLRequest 的时间设置为 2.5 秒，所以如果服务器有点慢我为什么要查找存储在 iPhone 中而不是服务器中的 JSON 文件。
如果我在飞行模式下测试我的应用程序，我的代码就像一个魅力，一切都从设备中读取，但如果我的覆盖率非常低或者我模拟了它，应用程序冻结，然后像在飞机上一样工作模式。
如果我在 Xcode 中添加断点，一切都会像往常一样执行（我的意思是快速），最后调用的函数是 viewWillAppear:.
有没有人有类似的问题？或者有人知道会发生什么吗？
任何想法将不胜感激。
提前致谢。
这是我用来获取 JSON 的函数：
-(NSData *)getMainMenuJsonData
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
if ([[defaults objectForKey:@"OnLine"] boolValue] )
NSString *urlAsString = [NSString stringWithFormat:@"%@%@/%@/%@",[configs valueForKey:@"wsURL"], [configs valueForKey:@"clientToken"], [configs valueForKey:@"appToken"], [CommonsUtils getCommonUtil].getAppLanguage];
NSURLRequest * urlRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:urlAsString] cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:2.5];
NSURLResponse * response = nil;
NSError * error = nil;
NSData * data = [NSURLConnection sendSynchronousRequest:urlRequest returningResponse:&response error:&error];
plistPath = [[NSBundle mainBundle] pathForResource:@"Config" ofType:@"plist"];
configs = [[NSDictionary alloc] initWithContentsOfFile:plistPath];
NSUInteger statusCode = ((NSHTTPURLResponse *)response).statusCode;
if (statusCode == 200 && error == Nil)
if (error != Nil)
return Nil;
else
return data;
else
return Nil;
else
return Nil;
-(NSData *)getSpecificJsonData:(NSString *)itemId
NSString *urlAsString = [NSString stringWithFormat:@"%@%@/%@/%@/%@",[configs valueForKey:@"wsURL"], [configs valueForKey:@"clientToken"], [configs valueForKey:@"appToken"], [CommonsUtils getCommonUtil].getAppLanguage, itemId];
NSURLRequest * urlRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:urlAsString] cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:2.5];
NSURLResponse * response = nil;
NSError * error = nil;
NSData * data = [NSURLConnection sendSynchronousRequest:urlRequest returningResponse:&response error:&error];
plistPath = [[NSBundle mainBundle] pathForResource:@"Config" ofType:@"plist"];
configs = [[NSDictionary alloc] initWithContentsOfFile:plistPath];
NSUInteger statusCode = ((NSHTTPURLResponse *)response).statusCode;
if (statusCode == 200 && error == Nil)
if (error != Nil)
return Nil;
else
return data;
else
return Nil;
这是我主屏幕的所有代码，一旦加载并调用 viewWillAppear:，如果我触摸屏幕上的一个按钮，执行 btnAction: 函数需要一段时间（如 30 秒或 1 分钟） ：
//
// vcMainScreen.m
// SmartHotel
//
// Created by GoSmart on 08/07/13.
// Copyright (c) 2013 GoSmart. All rights reserved.
//
#import "vcMainScreen.h"
#import "Util.h"
#import "Reachability.h"
#import "CommonsUtils.h"
@interface vcMainScreen ()
@property (nonatomic) Reachability *reachabilityInfo;
@end
@implementation vcMainScreen
NSDictionary *dValue;
NSData *jsonData;
NSDictionary *dConfiguration, *configs, *languages;
Util *util;
BOOL ok;
NSString *plistPath, *language;
@synthesize tabController;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self)
return self;
- (void)viewDidLoad
_reachabilityInfo = [Reachability reachabilityWithHostname:@"www.google.com"];
[_reachabilityInfo startNotifier];
[super viewDidLoad];
util = [[Util alloc] crearUtil];
[[self navigationController] setNavigationBarHidden:YES animated:NO];
NetworkStatus internetStatus = [_reachabilityInfo currentReachabilityStatus];
NSData *mainData = Nil;
if (internetStatus != NotReachable)
mainData = [util getMainMenuJsonData];
if (mainData != Nil)
jsonData = mainData;
else
plistPath = [[NSBundle mainBundle] pathForResource:@"Config" ofType:@"plist"];
configs = [[NSDictionary alloc] initWithContentsOfFile:plistPath];
languages = [configs valueForKey:@"Languages"];
for (NSString * appLanguage in [NSLocale preferredLanguages])
language = [[languages valueForKey:appLanguage] objectAtIndex:0];
if ([language isEqual:[NSNull null]])
language = [[languages valueForKey:@"default"] objectAtIndex:0];
else
break;
NSString *jsonPath = [NSString stringWithFormat:@"%@/%@.json",[NSSearchPathForDirectoriesInDomains (NSDocumentDirectory,NSUserDomainMask, YES) objectAtIndex:0],language];
jsonData = [NSData dataWithContentsOfFile:jsonPath];
dConfiguration =[NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:nil];
[self createTabBar];
NSInteger count = 0;
for (UIView* subView in self.view.subviews)
if ([subView isKindOfClass:[UIButton class]])
UIButton *bCustom = (UIButton *)subView;
[bCustom addTarget:self action:@selector(btnAction:) forControlEvents:UIControlEventTouchUpInside];
count ++;
dValue = [[dConfiguration objectForKey:@"BackgroundImage"] objectAtIndex:0];
_ivBackGround.image = [UIImage imageNamed:[util getBackgroundImageName:[dValue objectForKey:@"Image"] andRetrina:[dValue objectForKey:@"ImageRetina"]]];
self.navigationItem.title = @"Home";
- (void)viewWillAppear:(BOOL)animated
[self.navigationController setNavigationBarHidden:YES animated:animated];
[super viewWillAppear:animated];
// Tracking view for analytics
id tracker = [[GAI sharedInstance] defaultTracker];
[tracker set:kGAIScreenName value:self.navigationItem.title];
[tracker send:[[GAIDictionaryBuilder createAppView] build]];
- (void)viewWillDisappear:(BOOL)animated
[self.navigationController setNavigationBarHidden:YES animated:animated];
[super viewWillDisappear:animated];
- (BOOL)shouldAutorotate
return YES;
- (NSUInteger)supportedInterfaceOrientations
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone)
return UIInterfaceOrientationMaskPortrait;
else
return UIInterfaceOrientationMaskAll;
- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation
return UIInterfaceOrientationPortrait;
- (void)didReceiveMemoryWarning
[super didReceiveMemoryWarning];
- (void)createTabBar
tabController = [self.storyboard instantiateViewControllerWithIdentifier:@"cCustomTabController"];
dValue = [dConfiguration objectForKey:@"Buttons"];
NSMutableArray *aControllers = [[NSMutableArray alloc] init];
int i = 0;
for (NSString* sProperty in dValue)
NSString* d = @"Details";
NetworkStatus internetStatus = [_reachabilityInfo currentReachabilityStatus];
NSData *itemData = Nil;
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
if (internetStatus != NotReachable && [[defaults objectForKey:@"OnLine"] boolValue])
itemData = [util getSpecificJsonData:[sProperty valueForKeyPath:@"Item"]];
if(itemData != nil)
UIStoryboard *aStoryboard = [UIStoryboard storyboardWithName:@"Main_iPhone" bundle:[NSBundle mainBundle]];
UIViewController *vcCustom = [aStoryboard instantiateViewControllerWithIdentifier:[util getControllerName:[sProperty valueForKeyPath:@"ViewController"]]];
[vcCustom setValue:itemData forKey:@"JsonData"];
[vcCustom setValue:[sProperty valueForKeyPath:@"Item"] forKey:@"Item"];
[vcCustom setValue:d forKey:@"Details"];
[util saveJSON:itemData withName:[NSString stringWithFormat:@"%@%@",[sProperty valueForKeyPath:@"Item"],[CommonsUtils getCommonUtil].getAppLanguage]];
[[vcCustom navigationController] setNavigationBarHidden:NO animated:NO];
vcCustom.navigationItem.leftBarButtonItem = Nil;
vcCustom.navigationItem.hidesBackButton = YES;
UIImage *imageBtn = [UIImage imageNamed:[util getImageName:[sProperty valueForKeyPath:@"Image"] andRetrina:[sProperty valueForKeyPath:@"ImageRetina"]]];
UIImage *imageBtnPress = [UIImage imageNamed:[util getImageName:[sProperty valueForKeyPath:@"ImageHeighlighted"] andRetrina:[sProperty valueForKeyPath:@"ImageRetinaHeighlighted"]]];
UITabBarItem *tab = [[UITabBarItem alloc] initWithTitle:[sProperty valueForKeyPath:@"Title"] image:imageBtn selectedImage:imageBtnPress];
UIImage * iSelected = imageBtnPress;
iSelected = [iSelected imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
[tab setSelectedImage:iSelected];
tab.tag = i;
if([[sProperty valueForKeyPath:@"Title"] isEqualToString:@"Notificaciones"])
tab.badgeValue=[sProperty valueForKeyPath:@"Badge"];
[vcCustom setTabBarItem:tab];
[vcCustom setTitle:[sProperty valueForKeyPath:@"Title"]];
UINavigationController *navigationController = [[cCustomNavigationController alloc] initWithRootViewController:vcCustom];
navigationController.navigationBar.tintColor = [UIColor colorWithRed:36.0/255.0 green:134.0/255.0 blue:232.0/255.0 alpha:1];
[aControllers insertObject:navigationController atIndex:i];
i++;
else
UIStoryboard *aStoryboard = [UIStoryboard storyboardWithName:@"Main_iPhone" bundle:[NSBundle mainBundle]];
UIViewController *vcCustom = [aStoryboard instantiateViewControllerWithIdentifier:[util getControllerName:[sProperty valueForKeyPath:@"ViewController"]]];
NSNumber *val = [NSNumber numberWithInteger:i];
NSString *nextJson = [sProperty valueForKeyPath:@"JsonConfigFile"];
[vcCustom setValue:[sProperty valueForKeyPath:@"Item"] forKey:@"Item"];
[vcCustom setValue:nextJson forKey:@"JsonConfigFile"];
[vcCustom setValue:val forKey:@"MenuButtonSelectedTag"];
[[vcCustom navigationController] setNavigationBarHidden:NO animated:NO];
vcCustom.navigationItem.leftBarButtonItem = Nil;
vcCustom.navigationItem.hidesBackButton = YES;
UIImage *imageBtn = [UIImage imageNamed:[util getImageName:[sProperty valueForKeyPath:@"Image"] andRetrina:[sProperty valueForKeyPath:@"ImageRetina"]]];
UIImage *imageBtnPress = [UIImage imageNamed:[util getImageName:[sProperty valueForKeyPath:@"ImageHeighlighted"] andRetrina:[sProperty valueForKeyPath:@"ImageRetinaHeighlighted"]]];
UITabBarItem *tab = [[UITabBarItem alloc] initWithTitle:[sProperty valueForKeyPath:@"Title"] image:imageBtn selectedImage:imageBtnPress];
UIImage * iSelected = imageBtnPress;
iSelected = [iSelected imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
[tab setSelectedImage:iSelected];
tab.tag = i;
if([[sProperty valueForKeyPath:@"Title"] isEqualToString:@"Notificaciones"])
tab.badgeValue=[sProperty valueForKeyPath:@"Badge"];
[vcCustom setTabBarItem:tab];
[vcCustom setTitle:[sProperty valueForKeyPath:@"Title"]];
UINavigationController *navigationController = [[cCustomNavigationController alloc] initWithRootViewController:vcCustom];
navigationController.navigationBar.tintColor = [UIColor colorWithRed:36.0/255.0 green:134.0/255.0 blue:232.0/255.0 alpha:1];
[aControllers insertObject:navigationController atIndex:i];
i++;
tabController.delegate = self;
tabController.viewControllers = aControllers;
tabController.tabBar.tintColor = [UIColor blackColor];
-(BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController
return YES;
- (IBAction)btnAction:(id)sender
UIButton *bCustom = (UIButton *)sender;
tabController.selectedIndex = bCustom.tag;
id<GAITracker> tracker= [[GAI sharedInstance] defaultTracker];
[tracker send:[[GAIDictionaryBuilder createEventWithCategory: @"ui_button"
action: @"button_press"
label: [NSString stringWithFormat:@"%@-%@", self.title, [[tabController.viewControllers objectAtIndex:bCustom.tag] title]]
value: nil] build]];
[self.navigationController pushViewController:tabController animated:YES];
@end
这是我 iPhone 中的设置：
【问题讨论】：
您的问题是您使用的是sendSynchronousRequest。来自文档：“在异步加载系统执行 URL 加载时调用线程被阻塞 [...]”。当您从主线程调用它时，您正在阻止它并且 UI 变得无响应。这适用于稳定且快速的 Internet 连接，因为应用会挂起几毫秒，但在网络不佳时，挂起会非常明显。
@GuillaumeAlgis 但我不明白为什么当 UI 再次响应时，一切都像魅力一样工作，我每次触摸按钮时都会调用 getSpecificJsonData:itemId，所以它不能是 sendSynchronousRequest 会冻结我的屏幕一直都是，事实上，当我处于飞行模式时，每次触摸按钮时应用程序都会变得有点慢（2.5 秒），并且行为是预期的，但是在启动应用程序时覆盖率低，UI 冻结然后就像我在飞行模式下一样工作（每次触摸按钮慢 2.5 秒）
@GuillaumeAlgis 注意：我检测到有时函数 NetworkStatus internetStatus = [_reachabilityInfo currentReachabilityStatus] 返回 NotReachable 并且其他一些函数返回 ReachableViaWWAN 如果它是 ReachableViaWWAN 它将执行 sendSynchronousRequest 并且当它返回 NotReachable 时它不会执行 sendSynchronousRequest 并在这两种情况下 UI 冻结，这让我发疯了
【参考方案1】：
对此没有正确答案，由于@Guillaume Algis 和 this 我能够找到并解决我的问题。
一如既往地感谢您的帮助。
【讨论】：
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