【发布时间】：2012-05-01 09:19:03
【问题描述】：
我正在尝试实施this post 中给出的建议。
不幸的是，我不清楚这些步骤。我尝试实施这些建议，但即使在我启动和停止 locationServices 之后，backgroundTimeRemaining 也会继续减少。这就是我开发它的方式：
- (void)applicationDidEnterBackground:(UIApplication *)application {
UIApplication* app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
// Start the long-running task and return immediately.
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// Do the work associated with the task.
self.timer = nil;
[self initTimer];
});
}
初始化定时器：
- (void)initTimer {
// Create the location manager if this object does not
// already have one.
if (nil == self.locationManager)
self.locationManager = [[CLLocationManager alloc] init];
self.locationManager.delegate = self;
[self.locationManager startMonitoringSignificantLocationChanges];
if (self.timer == nil) {
self.timer = [NSTimer scheduledTimerWithTimeInterval:0.3
target:self
selector:@selector(checkUpdates:)
userInfo:nil
repeats:YES];
}
}
检查更新：
- (void)checkUpdates:(NSTimer *)timer{
UIApplication* app = [UIApplication sharedApplication];
double remaining = app.backgroundTimeRemaining;
if(remaining < 580.0) {
[self.locationManager startUpdatingLocation];
[self.locationManager stopUpdatingLocation];
[self.locationManager startMonitoringSignificantLocationChanges];
}
DbgLog(@"Reminaing %f", app.backgroundTimeRemaining);
}
是否有人对我的代码中可能存在的问题提出建议？ initTimer 和 checkUpdates 都被调用，但仅限于后台执行时间（+- 10 分钟）。我希望应用程序“永远”每 n 分钟更新一次位置。
我的应用的 UIBackgroundModes 设置为位置。
更新：
我现在正在重置 didUpdateToLocation 和 didFailWithError 上的计时器。但是 backgroundTimeRemaining 仍然在不断减少：
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation {
NSLog(@"Did Update Location = %f / %f", [newLocation coordinate].latitude, [newLocation coordinate].longitude);
UIApplication* app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
// Start the long-running task and return immediately.
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// Do the work associated with the task.
[self initTimer];
});
}
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
[self.locationManager stopUpdatingLocation];
UIApplication* app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
// Start the long-running task and return immediately.
[self initTimer];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// Do the work associated with the task.
});
}
我也让计时器失效：
- (void)checkUpdates:(NSTimer *)timer{
UIApplication* app = [UIApplication sharedApplication];
double remaining = app.backgroundTimeRemaining;
if(remaining < 580.0 && remaining > 570.0) {
[self.timer invalidate];
self.timer = nil;
[self.locationManager startUpdatingLocation];
[self.locationManager stopUpdatingLocation];
}
DbgLog(@"*************************Checking for updates!!!!!!!!!!! Reminaing %f", app.backgroundTimeRemaining);
}
【问题讨论】：
-
App Store 是否接受您的应用程序？我正在考虑采用相同的方法，但我需要确保我的应用不会被拒绝。谢谢顺便说一句！
-
你让它工作了吗/？
-
@scurioni 如何在“冷却”期间移除状态栏图标（在 stopUpdatingLocation 到下一个 startUpdatingLocation 之间）？即使在调用 stopUpdatingLocation 之后它仍然存在。该图标只有在显式调用 stopUpdatingLocation （从 ViewController 或类似的东西）后才会消失
标签： ios objective-c iphone background locationmanager