iOS屏幕尺寸和分辨率了解

1、截至目前为止，主流的iOS设备屏幕有以下几种：

--------------- iPhone ---------- -------- iPad ------------

2、iOS设备屏幕分辨率：（ppi是像素密度单位【像素/英寸】，401ppi表示每英寸上有401个像素）

　　ppi(pixel per inch)计算，以6Plus为例：

　　屏幕分辨率1920 x 1080, 屏幕尺寸5.5英寸(手机屏幕对角物理线的长度)，

　　1920 x 1920 + 1080 x 1080 = 4852800, 开根号为：2202.907...

　　2202.907 / 5.5 ＝ 400.528 ppi，大约就是401ppi

3、iOS的三种分辨率

　 1）、资源分辨率：资源图片的大小，单位是像素。

　 2）、设计分辨率：逻辑上的屏幕大小，单位是点。我们在Interface Builder设计器中的单位和程序代码中的单位都是设计分辨率中的“点”。

　 3）、是以像素为单位的屏幕大小，所有的应用都会渲染到这个屏幕上展示给用户。

iPhone 6 Plus和 6S Plus是最为特殊的设备，资源分辨率与屏幕分辨率的比例是1.15 : 1, 而其他的设备比例是1 : 1。不同的人群关注的分辨率也是不同的，UI设计人员主要关注的是资源分辨率，开发人员主要关注的是设计分辨率，而一般用户主要关注的屏幕分辨率。

4、获取设备屏幕信息

　　获取当前移动设备对象：[UIDevice currentDevice]

　　UIDevice类所有信息

NS_CLASS_AVAILABLE_IOS(2_0) @interface UIDevice : NSObject + (UIDevice *)currentDevice;@property(nonatomic,readonly,strong) NSString    *name;              // e.g. "My iPhone"
@property(nonatomic,readonly,strong) NSString    *model;             // e.g. @"iPhone", @"iPod touch"
@property(nonatomic,readonly,strong) NSString    *localizedModel;    // localized version of model
@property(nonatomic,readonly,strong) NSString    *systemName;        // e.g. @"iOS"
@property(nonatomic,readonly,strong) NSString    *systemVersion;     // e.g. @"4.0"
@property(nonatomic,readonly) UIDeviceOrientation orientation __TVOS_PROHIBITED;       // return current device orientation.  this will return UIDeviceOrientationUnknown unless device orientation notifications are being generated.

@property(nullable, nonatomic,readonly,strong) NSUUID      *identifierForVendor NS_AVAILABLE_IOS(6_0);      // a UUID that may be used to uniquely identify the device, same across apps from a single vendor.

@property(nonatomic,readonly,getter=isGeneratingDeviceOrientationNotifications) BOOL generatesDeviceOrientationNotifications __TVOS_PROHIBITED;
- (void)beginGeneratingDeviceOrientationNotifications __TVOS_PROHIBITED;      // nestable
- (void)endGeneratingDeviceOrientationNotifications __TVOS_PROHIBITED;@property(nonatomic,getter=isBatteryMonitoringEnabled) BOOL batteryMonitoringEnabled NS_AVAILABLE_IOS(3_0) __TVOS_PROHIBITED;  // default is NO
@property(nonatomic,readonly) UIDeviceBatteryState          batteryState NS_AVAILABLE_IOS(3_0) __TVOS_PROHIBITED;  // UIDeviceBatteryStateUnknown if monitoring disabled
@property(nonatomic,readonly) float                         batteryLevel NS_AVAILABLE_IOS(3_0) __TVOS_PROHIBITED;  // 0 .. 1.0. -1.0 if UIDeviceBatteryStateUnknown

@property(nonatomic,getter=isProximityMonitoringEnabled) BOOL proximityMonitoringEnabled NS_AVAILABLE_IOS(3_0); // default is NO
@property(nonatomic,readonly)                            BOOL proximityState NS_AVAILABLE_IOS(3_0);  // always returns NO if no proximity detector

@property(nonatomic,readonly,getter=isMultitaskingSupported) BOOL multitaskingSupported NS_AVAILABLE_IOS(4_0);@property(nonatomic,readonly) UIUserInterfaceIdiom userInterfaceIdiom NS_AVAILABLE_IOS(3_2);- (void)playInputClick NS_AVAILABLE_IOS(4_2);  // Plays a click only if an enabling input view is on-screen and user has enabled input clicks.@end

ios移动设备类型枚举判断：

typedef NS_ENUM(NSInteger, UIUserInterfaceIdiom) {UIUserInterfaceIdiomUnspecified = -1,UIUserInterfaceIdiomPhone NS_ENUM_AVAILABLE_IOS(3_2), // iPhone and iPod touch style UIUIUserInterfaceIdiomPad NS_ENUM_AVAILABLE_IOS(3_2), // iPad style UIUIUserInterfaceIdiomTV NS_ENUM_AVAILABLE_IOS(9_0), // Apple TV style UI
};

[UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPhone // 表示iPhone设备

[UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPad // 表示iPad设备

[UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomTV // 表示Apple TV设备

[UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomUnspecified // 表示未知设备

//示例：详细判断iPhone设备类型

//详细判断iPhone设备信息, 区分横屏和竖屏if ([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPhone){//获取屏幕尺寸信息CGSize screenSize = [UIScreen mainScreen].bounds.size;//竖屏情况if (screenSize.height > screenSize.width){if (screenSize.height == 568){//iPhone 5/5S/5C (iPod / iPod touch) 等设备
            }else if (screenSize.height == 667){//iPone 6 / 6S 等设备
            }else if (screenSize.height == 736){//iPone 6 Plus / 6S Plus 等设备
            }else{//iPhone 4 / 4S 等设备
            }}//横屏情况if (screenSize.width > screenSize.height){if (screenSize.width == 568){//iPhone 5/5S/5C (iPod / iPod touch) 等设备
            }else if (screenSize.width == 667){//iPone 6 / 6S 等设备
            }else if (screenSize.width == 736){//iPone 6 Plus / 6S Plus 等设备
            }else{//iPhone 4 / 4S 等设备
            }}}