关于相机相册的一些实用技术

最近做项目遇到了一些问题，就搜集了一些资料，集中在了一起
感谢：
CSDN 博主 [小手一背爱谁谁]
http://blog.csdn.net/saw471/article/details/52679746
wentian的博客
http://www.2cto.com/kf/201608/532614.html
本人只是搬运工，如有冒犯，请见谅！

一、权限状态说明

相册、相机、通讯录等授权状态目前都有种，都可以对应以下几种状态：

AuthorizationStatusNotDetermined      // 用户从未进行过授权等处理，首次访问相应内容会提示用户进行授权
AuthorizationStatusAuthorized = 0,    // 用户已授权，允许访问
AuthorizationStatusDenied,            // 用户拒绝访问
AuthorizationStatusRestricted,        // 应用没有相关权限，且当前用户无法改变这个权限，比如:家长控制

二、权限获取(以下都是iOS8之后的)
1.相册权限
是否支持

[UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]

获取权限状态

PHAuthorizationStatus authStatus = [PHPhotoLibrary authorizationStatus];

请求权限

[PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
                }];

权限状态

typedef NS_ENUM(NSInteger, PHAuthorizationStatus) {
    PHAuthorizationStatusNotDetermined = 0, // User has not yet made a choice with regards to this application
    PHAuthorizationStatusRestricted,        // This application is not authorized to access photo data.
                                            // The user cannot change this application’s status, possibly due to active restrictions
                                            //   such as parental controls being in place.
    PHAuthorizationStatusDenied,            // User has explicitly denied this application access to photos data.
    PHAuthorizationStatusAuthorized         // User has authorized this application to access photos data.
} NS_AVAILABLE_IOS(8_0);

2.拍照权限
是否支持

[UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]

获取权限状态

AVAuthorizationStatus authStatus = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];

请求权限

[PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
                }];

权限状态

typedef NS_ENUM(NSInteger, AVAuthorizationStatus) {
    AVAuthorizationStatusNotDetermined = 0,
    AVAuthorizationStatusRestricted,
    AVAuthorizationStatusDenied,
    AVAuthorizationStatusAuthorized
} NS_AVAILABLE_IOS(7_0) __TVOS_PROHIBITED;

三、拒绝授权的处理
用户拒绝授权后，如果访问相应内容可能会出现一些类似没有数据的情况，此时应该给用户提示，引导用户授权。

跳转到应用设置：

NSURL *settingUrl = [NSURL URLWithString:UIApplicationOpenSettingsURLString];
if ([[UIApplication sharedApplication] canOpenURL:settingUrl]) {
    [[UIApplication sharedApplication] openURL:settingUrl];
}

四、info.plist 里面的相关配置

<!-- 相册 -->   
<key>NSPhotoLibraryUsageDescription</key>   
<string>App需要您的同意,才能访问相册</string>   

<!-- 相机 -->   
<key>NSCameraUsageDescription</key>   
<string>App需要您的同意,才能访问相机</string>   

<!-- 麦克风 -->   
<key>NSMicrophoneUsageDescription</key>   
<string>App需要您的同意,才能访问麦克风</string>   

<!-- 位置 -->   
<key>NSLocationUsageDescription</key>   
<string>App需要您的同意,才能访问位置</string>   

<!-- 在使用期间访问位置 -->   
<key>NSLocationWhenInUseUsageDescription</key>   
<string>App需要您的同意,才能在使用期间访问位置</string>   

<!-- 始终访问位置 -->   
<key>NSLocationAlwaysUsageDescription</key>   
<string>App需要您的同意,才能始终访问位置</string>   

<!-- 日历 -->   
<key>NSCalendarsUsageDescription</key>   
<string>App需要您的同意,才能访问日历</string>   

<!-- 提醒事项 -->   
<key>NSRemindersUsageDescription</key>   
<string>App需要您的同意,才能访问提醒事项</string>   

<!-- 运动与健身 -->   
<key>NSMotionUsageDescription</key> <string>App需要您的同意,才能访问运动与健身</string>   

<!-- 健康更新 -->   
<key>NSHealthUpdateUsageDescription</key>   
<string>App需要您的同意,才能访问健康更新 </string>   

<!-- 健康分享 -->   
<key>NSHealthShareUsageDescription</key>   
<string>App需要您的同意,才能访问健康分享</string>   

<!-- 蓝牙 -->   
<key>NSBluetoothPeripheralUsageDescription</key>   
<string>App需要您的同意,才能访问蓝牙</string>   

<!-- 媒体资料库 -->   
<key>NSAppleMusicUsageDescription</key>  <string>App需要您的同意,才能访问媒体资料库</string>  

*有个封装的工具类，可使用WTAuthorizationTool，里面还有通讯录的权限

pod "WTAuthorizationTool"