在xx-info.plist 里的 "Required background modes" 里加入"App provides Voice over IP services"
然后在delegate里加入以下代码，原理是进入后台时程序会在600秒那样结束任务，我做的就是在结束任务前新开一个任务，再结束旧任务，这样就一直的在后台运行，原链接：http://www.devdiv.com/forum.php?mod=viewthread&tid=200491
#import "AppDelegate.h"
#import "ViewController.h"
@interface AppDelegate ()
{
UIBackgroundTaskIdentifier backgroundTaskIdentifier;
UIBackgroundTaskIdentifier oldBackgroundTaskIdentifier;
NSInteger count;
}
@property (nonatomic,strong) NSTimer *timer;
@end
@implementation AppDelegate
//-(NSTimer *)timer{
// if (_timer==nil) {
// _timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timerFired) userInfo:nil repeats:YES];
//
// [_timer fire];
// }
// return _timer;
//}
- (BOOL) isMultitaskingSupported{
BOOL result = NO;
if ([[UIDevice currentDevice]
respondsToSelector:@selector(isMultitaskingSupported)]){ result = [[UIDevice currentDevice] isMultitaskingSupported];
}
return result;
}
- (void) timerMethod:(NSTimer *)paramSender{
count++;
if (count % 500 == 0) {
UIApplication *application = [UIApplication sharedApplication];
//开启一个新的后台
backgroundTaskIdentifier = [application beginBackgroundTaskWithExpirationHandler:^{
}];
//结束旧的后台任务
[application endBackgroundTask:backgroundTaskIdentifier];
oldBackgroundTaskIdentifier = backgroundTaskIdentifier;
}
NSLog(@"%ld",count);
}
- (void)applicationDidEnterBackground:(UIApplication *)application
{
if ([self isMultitaskingSupported] == NO){
return; }
//开启一个后台任务
backgroundTaskIdentifier = [application beginBackgroundTaskWithExpirationHandler:^{
}];
oldBackgroundTaskIdentifier = backgroundTaskIdentifier;
if ([self.timer isValid]) {
[self.timer invalidate];
}
self.timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timerMethod:) userInfo:nil repeats:YES];
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
// ViewController *vc = [[ViewController alloc] init];
// UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:vc];
// self.window.rootViewController = vc;
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
// [[UIApplication sharedApplication] setMinimumBackgroundFetchInterval:UIApplicationBackgroundFetchIntervalMinimum];
// [self timer];
// [[UIApplication sharedApplication] setMinimumBackgroundFetchInterval:10000];
return YES;
}
- (void)applicationWillResignActive:(UIApplication *)application {
// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
// Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}
-(void)backgroundHandler{
[self timer];
}
-(void)timerFired{
NSLog(@"%s %@",__func__,_timer);
}
- (void)applicationWillEnterForeground:(UIApplication *)application
{
if (backgroundTaskIdentifier != UIBackgroundTaskInvalid){
[application endBackgroundTask:backgroundTaskIdentifier];
if ([self.timer isValid]) {
[self.timer invalidate];
}
}
}
- (void)applicationDidBecomeActive:(UIApplication *)application {
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}
- (void)applicationWillTerminate:(UIApplication *)application {
// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}
@end
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