如何判断设备电量

 - (void)batteryMoniter {
     UIDevice *device = [UIDevice currentDevice];
     device.batteryMonitoringEnabled = YES;
     if (device.batteryState == UIDeviceBatteryStateUnknown) {
         NSLog(@"UnKnow");
     }else if (device.batteryState == UIDeviceBatteryStateUnplugged){
         NSLog(@"Unplugged");
     }else if (device.batteryState == UIDeviceBatteryStateCharging){
         NSLog(@"Charging");
     }else if (device.batteryState == UIDeviceBatteryStateFull){
         NSLog(@"Full");
     }
     NSLog(@"%f",device.batteryLevel);
 }

 NSLog(@"%f",device.batteryLevel);//简单的这句就是了。

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 Having said that, I would not use a timer event for this, it is pretty inefficient. You want to use KVO instead:

 - (void) viewWillAppear:(BOOL)animated {
   UIDevice *device = [UIDevice currentDevice];
   device.batteryMonitoringEnabled = YES;
   currentCharge.text = [NSString stringWithFormat:@"%.2f", device.batteryLevel];
   [device addObserver:self forKeyPath:@"batteryLevel" options:0x0 context:nil];
   [super viewWillAppear:animated];
 }

 - (void) viewDidDisappear:(BOOL)animated {
   UIDevice *device = [UIDevice currentDevice];
   device.batteryMonitoringEnabled = NO;
   [device removeObserver:self forKeyPath:@"batteryLevel"];
   [super viewDidDisappear:animated];
 }

 - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
   UIDevice *device = [UIDevice currentDevice];
   if ([object isEqual:device] && [keyPath isEqual:@"batteryLevel"]) {
     currentCharge.text = [NSString stringWithFormat:@"%.2f", device.batteryLevel];
   }
 }