好的,所以我想让这个应用程序显示网络错误警报代码。我添加了SystemConfiguration.framework框架和Apple的“Reachability”示例代码。
这是viewcontroller.h文件:
#import <UIKit/UIKit.h>
@class Reachability;
@interface Test_Internet_ConnectionViewController : UIViewController {
Reachability* internetReachable;
Reachability* hostReachable;
}
@property BOOL internetActive;
@property BOOL hostActive;
- (void) checkNetworkStatus:(NSNotification *)notice;
@end
这是viewcontroller.m文件:
#import "Test_Internet_ConnectionViewController.h"
#import "Reachability.h";
@implementation Test_Internet_ConnectionViewController
@synthesize internetActive;
@synthesize hostActive;
/*
// The designated initializer. Override to perform setup that is required before the view is loaded.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
*/
/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
[super viewDidLoad];
// check for internet connection
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(checkNetworkStatus:) name:kReachabilityChangedNotification object:nil];
internetReachable = [[Reachability reachabilityForInternetConnection] retain];
[internetReachable startNotifier];
// check if a pathway to a random host exists
hostReachable = [[Reachability reachabilityWithHostName: @"www.apple.com"] retain];
[hostReachable startNotifier];
// now patiently wait for the notification
}
/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// Return YES for supported orientations
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
- (void)viewDidUnload {
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void) checkNetworkStatus:(NSNotification *)notice
{
// called after network status changes
NetworkStatus internetStatus = [internetReachable currentReachabilityStatus];
switch (internetStatus)
{
case NotReachable:
{
NSLog(@"The internet is down.");
self.internetActive = NO;
UIAlertView *errorView = [[UIAlertView alloc] initWithTitle:@"Internet Unavailable" message:@"This page cannot load, please check your internet connection and try again." delegate:nil cancelButtonTitle:@"Dismiss" otherButtonTitles:nil];
[errorView show];
[errorView release];
break;
}
case ReachableViaWiFi:
{
NSLog(@"The internet is working via WIFI.");
self.internetActive = YES;
break;
}
case ReachableViaWWAN:
{
NSLog(@"The internet is working via WWAN.");
self.internetActive = YES;
break;
}
}
NetworkStatus hostStatus = [hostReachable currentReachabilityStatus];
switch (hostStatus)
{
case NotReachable:
{
NSLog(@"A gateway to the host server is down.");
self.hostActive = NO;
break;
}
case ReachableViaWiFi:
{
NSLog(@"A gateway to the host server is working via WIFI.");
self.hostActive = YES;
break;
}
case ReachableViaWWAN:
{
NSLog(@"A gateway to the host server is working via WWAN.");
self.hostActive = YES;
break;
}
}
}
- (void)dealloc {
[super dealloc];
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
@end
如果在打开应用程序时没有互联网,则错误按预期工作,但如果应用程序在最初使用互联网连接打开后失去连接,则错误显示3次,此时我显然只希望显示一次。
有人可以帮帮我吗? 提前谢谢。
答案 0 :(得分:1)
错误View委托可能应该是self而不是nil,但我不确定这是否能解决问题。如果没有,问题可能是NSNotificationCenter
向观察者发送了太多通知(在这种情况下为checkNetworkStatus
。最简单(但可能不太优雅)的解决方案是保留通知计数器显示错误视图时增加的变量,如果计数器为零,则仅显示错误视图。更好的解决方案是检查传入的通知,并以不同的方式响应不同的通知(或根本不响应)。