iOS获取电池电量

1. 方案一：IOKit.framework
   这个被是苹果的私有，一旦使用，不给上架
2. 
   
3. UIDevice public API
   

     [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);
    }];  
   

4. 更精准的方案，通过runtime去捕获私电池电量控件类私有变量的值

- (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;
}