1.获取设备方向

typedef NS_ENUM(NSInteger, UIDeviceOrientation) {
    UIDeviceOrientationUnknown,
    UIDeviceOrientationPortrait,            // 设备垂直竖向方向放置, 并且home键在下方
    UIDeviceOrientationPortraitUpsideDown,  //设备垂直竖向方向放置, 并且home键在上方
    UIDeviceOrientationLandscapeLeft,       // 设备垂直横向方向放置, 并且home键在右方
    UIDeviceOrientationLandscapeRight,      // 设备垂直横向方向放置, 并且home键在左方
    UIDeviceOrientationFaceUp,              // 设备水平放置, 屏幕在上方
    UIDeviceOrientationFaceDown             // 设备水平放置, 屏幕在下方
} （TVOS不可用）

判断当前设备方向

//但这个有个弊端，就是没有设备方向改变通知时，返回UIDeviceOrientationUnknown
if([[UIDevice currentDevice] orientation] == UIDeviceOrientationPortrait){
    NSLog(@"当前设备是垂直竖向，并且home键在下方");
}
//竖屏，包括UIDeviceOrientationPortrait || UIDeviceOrientationPortraitUpsideDown
if (UIDeviceOrientationIsPortrait([UIDevice currentDevice].orientation)) {
    NSLog(@"竖屏");
}
//横屏，包括UIDeviceOrientationLandscapeLeft || UIDeviceOrientationLandscapeRight
if (UIDeviceOrientationIsLandscape([UIDevice currentDevice].orientation)) {
    NSLog(@"横屏");
}

//所以推荐下面的方式
if (![UIDevice currentDevice].generatesDeviceOrientationNotifications) {
   [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
 }
if([[UIDevice currentDevice] orientation] == UIDeviceOrientationPortrait){
    NSLog(@"当前设备是垂直竖向，并且home键在下方");
}
[[UIDevice currentDevice] endGeneratingDeviceOrientationNotifications];

2.获取设备电池状态

typedef NS_ENUM(NSInteger, UIDeviceBatteryState) {
    UIDeviceBatteryStateUnknown,
    UIDeviceBatteryStateUnplugged,   // 未充电，使用电池
    UIDeviceBatteryStateCharging,    // 充电中，并且电量小于 100%
    UIDeviceBatteryStateFull,        // 充电中, 电量已达 100%
} __TVOS_PROHIBITED;              // TVOS不可用，iOS3之后可用

判断当前设备电池状态

[UIDevice currentDevice].batteryMonitoringEnabled = YES; //开启电量监控，默认不开启
if ([[UIDevice currentDevice] batteryState] == UIDeviceBatteryStateCharging){
    NSLog(@"正在充电中，且电量不足100");
}
//当前电量，小数[0,1] ,如果[[UIDevice currentDevice] batteryState] == UIDeviceBatteryStateUnknown时，则为1.0
NSLog(@"当前电量%f",[[UIDevice currentDevice] batteryLevel]);

3.获取设备类型

typedef NS_ENUM(NSInteger, UIUserInterfaceIdiom) {
    UIUserInterfaceIdiomUnspecified = -1,
    UIUserInterfaceIdiomPhone NS_ENUM_AVAILABLE_IOS(3_2), // 0,iPhone and iPod touch style UI
    UIUserInterfaceIdiomPad NS_ENUM_AVAILABLE_IOS(3_2), // 1,iPad style UI
    UIUserInterfaceIdiomTV NS_ENUM_AVAILABLE_IOS(9_0), // 2,Apple TV style UI
    UIUserInterfaceIdiomCarPlay NS_ENUM_AVAILABLE_IOS(9_0), //3, CarPlay style UI
};

NSLog(@"%ld",(long)[UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPhone) //判断是否为iPhone或者iPod

4.修改某个界面的横竖屏状态

上述方法只能获取设备的当前屏幕状态，不能修改，如果想要修改，请参考下面的方法
iOS6之前

// Applications should use supportedInterfaceOrientations and/or shouldAutorotate..
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation NS_DEPRECATED_IOS(2_0, 6_0) __TVOS_PROHIBITED;

示例

//始终保持竖屏
- (BOOL) shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation
{
    return (toInterfaceOrientation == UIInterfaceOrientationPortrait);
}

iOS6之后

//是否支持旋转
- (BOOL)shouldAutorotate NS_AVAILABLE_IOS(6_0) __TVOS_PROHIBITED;
//支持的旋转方向
- (UIInterfaceOrientationMask)supportedInterfaceOrientations NS_AVAILABLE_IOS(6_0) __TVOS_PROHIBITED;

• 全部界面采用同一种
  如果window.rootViewController是UINavigationViewController的话，只要在导航控制器中设置完毕之后，所有push出来的viewController，都是和NavigationViewController一样

- (BOOL)shouldAutorotate {
    return YES;
}

- (NSUInteger)supportedInterfaceOrientations {
    return UIInterfaceOrientationMaskPortrait;
}

• 多个界面，采用各自的屏幕需求，在NavigationViewController中实现下面的方法，指定每个ViewController按照自己的需求改变，在ViewController中覆写此方法

- (BOOL)shouldAutorotate {
    if (self.topViewController != nil) return [self.topViewController shouldAutorotate];
    else return [super shouldAutorotate];
}

- (NSUInteger)supportedInterfaceOrientations {
    if (self.topViewController != nil) return [self.topViewController supportedInterfaceOrientations];
    else return [super supportedInterfaceOrientations];
}