iOS 获取剩余电量

最简单的

[UIDevice currentDevice].batteryMonitoringEnabled = YES;  double deviceLevel = [UIDevice currentDevice].batteryLevel;  

方法一：通过苹果官方文档里面UIDevice public API来获取，代码如下：

  [UIDevice currentDevice].batteryMonitoringEnabled = YES;  [[NSNotificationCenter defaultCenter] addObserverForName:UIDeviceBatteryLevelDidChangeNotification object:nil queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *notification) {     // Level has changed     NSLog(@"Battery Level Change");     NSLog(@"电池电量：%.2f", [UIDevice currentDevice].batteryLevel); }];@property(nonatomic,readonly) float     batteryLevel NS_AVAILABLE_IOS(3_0);  // 0 .. 1.0. -1.0 if UIDeviceBatteryStateUnknown它返回的是0.00-1.00之间的浮点值。

但是经过测试发现，在iOS7 上 它是以0.05为单位的，但是在iOS9下测试，它是以0.01为单位的，虽然也是0.01为单位，但是测试多次也会出现偏差1%左右。也就是说, 这个办法是存在缺陷的, 最起码, 它不精确。

方法二：找到Mac下IOKit.framework，将IOKit.framework里面的IOPowerSources.h和IOPSKeys.h拷贝到你的iOS项目中。另外, 还需要把IOKit也导入到你的工程中去，此方法也会出现偏差，不精确。DEMO 地址：https://github.com/colin1994/batteryLevelTest.git

/** *  Calculating the remaining energy * *  @return Current batterylevel */  -(double)getCurrentBatteryLevel  {  //Returns a blob of Power Source information in an opaque CFTypeRef.  CFTypeRef blob = IOPSCopyPowerSourcesInfo();  //Returns a CFArray of Power Source handles, each of type CFTypeRef.  CFArrayRef sources = IOPSCopyPowerSourcesList(blob);  CFDictionaryRef pSource = NULL;  const void *psValue;  //Returns the number of values currently in an array.  int numOfSources = CFArrayGetCount(sources);  //Error in CFArrayGetCount  if (numOfSources == 0)  {      NSLog(@"Error in CFArrayGetCount");      return -1.0f;  }  //Calculating the remaining energy  for (int i = 0 ; i < numOfSources ; i++)  {      //Returns a CFDictionary with readable information about the specific power source.      pSource = IOPSGetPowerSourceDescription(blob, CFArrayGetValueAtIndex(sources, i));      if (!pSource)      {          NSLog(@"Error in IOPSGetPowerSourceDescription");          return -1.0f;      }      psValue = (CFStringRef)CFDictionaryGetValue(pSource, CFSTR(kIOPSNameKey));      int curCapacity = 0;      int maxCapacity = 0;      double percent;      psValue = CFDictionaryGetValue(pSource, CFSTR(kIOPSCurrentCapacityKey));      CFNumberGetValue((CFNumberRef)psValue, kCFNumberSInt32Type, &curCapacity);      psValue = CFDictionaryGetValue(pSource, CFSTR(kIOPSMaxCapacityKey));      CFNumberGetValue((CFNumberRef)psValue, kCFNumberSInt32Type, &maxCapacity);      percent = ((double)curCapacity/(double)maxCapacity * 100.0f);      return percent;  }  return -1.0f;  }

方法三:通过runtime 获取StatusBar上电池电量控件类私有变量的值，此方法可精准获取iOS6以上电池电量

MRC:- (int)getCurrentBatteryLevel{ if ([UIApplication sharedApplication].applicationState == UIApplicationStateActive||[UIApplication sharedApplication].applicationState==UIApplicationStateInactive) {        void *result = nil;        object_getInstanceVariable([UIApplication sharedApplication], "_statusBar", &result);        id status  = result;        for (id aview in [status subviews]) {            for (id bview in [aview subviews]) {                int batteryLevel = 0;               if ([NSStringFromClass([bview class]) caseInsensitiveCompare:@"UIStatusBarBatteryItemView"] == NSOrderedSame&&[[[UIDevice currentDevice] systemVersion] floatValue] >= 6.0)                {                    object_getInstanceVariable(bview, "_capacity", &result);                    batteryLevel = (int)result;                    NSLog(@"电池电量:%d",batteryLevel);                    if (batteryLevel > 0 && batteryLevel <= 100) {                        return batteryLevel;                    } else {                        return 0;                    }                }        }    }    return 0;}ARC:- (int)getCurrentBatteryLevel{UIApplication *app = [UIApplication sharedApplication];if (app.applicationState == UIApplicationStateActive||app.applicationState==UIApplicationStateInactive) {    Ivar ivar=  class_getInstanceVariable([app class],"_statusBar");    id status  = object_getIvar(app, ivar);    for (id aview in [status subviews]) {        int batteryLevel = 0;        for (id bview in [aview subviews]) {            if ([NSStringFromClass([bview class]) caseInsensitiveCompare:@"UIStatusBarBatteryItemView"] == NSOrderedSame&&[[[UIDevice currentDevice] systemVersion] floatValue] >=6.0)            {                    Ivar ivar=  class_getInstanceVariable([bview class],"_capacity");                    if(ivar)                    {                        batteryLevel = ((int (*)(id, Ivar))object_getIvar)(bview, ivar);                        //这种方式也可以                        /*ptrdiff_t offset = ivar_getOffset(ivar);                         unsigned char *stuffBytes = (unsigned char *)(__bridge void *)bview;                         batteryLevel = * ((int *)(stuffBytes + offset));*/                        NSLog(@"电池电量:%d",batteryLevel);                        if (batteryLevel > 0 && batteryLevel <= 100) {                            return batteryLevel;                        } else {                            return 0;                        }                    }            }        }    }}return 0;}