iOS之访问权限以及跳转到系统界面

iOS开发中有时候有这样的需求：当用户设置不允许访问照片、麦克风和相机等系统权限的时候，这时需要直接跳转到系统的隐私界面进行设置。

判断是否开启权限

前面已经说过，我们需要在用户不允许访问的时候跳转，那么首先我们就要判断一些是否已经开启系统相机权限了。

照片权限检测

需要：#import <AssetsLibrary/AssetsLibrary.h> //导入此类和AssetsLibrary.framework框架

代码如下：

int author = [ALAssetsLibrary authorizationStatus];
            NSLog(@"author type:%d",author);
            if(author == ALAuthorizationStatusRestricted || author == ALAuthorizationStatusDenied) {
                // The user has explicitly denied permission for media capture.
                UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"无法使用相册"
                                                                message:@"请在iPhone的\"设置-隐私-照片\"中允许访问照片。"
                                                               delegate:self
                                                      cancelButtonTitle:@"确定"
                                                      otherButtonTitles:nil];
                [alert show];
                return;

ALAssetsLibrary类

ALAssetsLibrary类是代表系统中整个资源库，使用它可以访问资源库中的资源和保存照片，视频等功能。

    //判断当前应用是否能访问相册资源
    /*
     typedef NS_ENUM(NSInteger, ALAuthorizationStatus) {
     ALAuthorizationStatusNotDetermined = 0, 用户尚未做出了选择这个应用程序的问候
     ALAuthorizationStatusRestricted,        此应用程序没有被授权访问的照片数据。可能是家长控制权限。
     ALAuthorizationStatusDenied,            用户已经明确否认了这一照片数据的应用程序访问.
     ALAuthorizationStatusAuthorized         用户已授权应用访问照片数据.
     }
     */

访问摄像头

需要：#import <AVFoundation/AVFoundation.h>

代码如下：

if(isIOS7AndLater) {

NSString *mediaType = AVMediaTypeVideo;// Or AVMediaTypeAudio
        AVAuthorizationStatus authStatus = [AVCaptureDevice authorizationStatusForMediaType:mediaType];
        NSLog(@"---cui--authStatus--------%d",authStatus);
        // This status is normally not visible—the AVCaptureDevice class methods for discovering devices do not return devices the user is restricted from accessing.
        if(authStatus ==AVAuthorizationStatusRestricted){
            NSLog(@"Restricted");
        }else if(authStatus == AVAuthorizationStatusDenied){
            // The user has explicitly denied permission for media capture.
            NSLog(@"Denied");     //应该是这个，如果不允许的话
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示"
                                                            message:@"请在设备的\"设置-隐私-相机\"中允许访问相机。"
                                                           delegate:self
                                                  cancelButtonTitle:@"确定"
                                                  otherButtonTitles:nil];
            [alert show];
            return;
        }
        else if(authStatus == AVAuthorizationStatusAuthorized){//允许访问
            // The user has explicitly granted permission for media capture, or explicit user permission is not necessary for the media type in question.
            NSLog(@"Authorized");

        }else if(authStatus == AVAuthorizationStatusNotDetermined){
            // Explicit user permission is required for media capture, but the user has not yet granted or denied such permission.
            [AVCaptureDevice requestAccessForMediaType:mediaType completionHandler:^(BOOL granted) {
                if(granted){//点击允许访问时调用
                    //用户明确许可与否，媒体需要捕获，但用户尚未授予或拒绝许可。
                    NSLog(@"Granted access to %@", mediaType);
                }
                else {
                    NSLog(@"Not granted access to %@", mediaType);
                }

            }];
        }else {
            NSLog(@"Unknown authorization status");
        }
}

麦克风权限检测

代码如下：

  //检测麦克风功能是否打开
    [[AVAudioSessionsharedInstance]requestRecordPermission:^(BOOL granted) {
        if (!granted)
        {
            [ViewUtilalertViewWithString:NSLocalizedString(@"麦克风功能未开启",nil)];
        }
        else
        {

            [selfrecord:sender];
        }
    }];

如何跳转到系统设置界面

判断权限是否设置之后就可以在相应的代理方法进行界面跳转了，那么如何进行跳转呢？

首先要在项目中的info.plist中添加 URL types 并设置一项URL Schemes为prefs，如下图：

1.jpg

实现代码如下：

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:url]];//url为具体路径

以下是跳转到一些常用界面的代码

隐私->照片界面

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"prefs:root=Privacy&path=PHOTOS"]];

隐私->相机界面

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"prefs:root=Privacy&path=CAMERA"]];

蓝牙设置界面

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"prefs:root=Bluetooth"]];

其他界面参数配置

About — prefs:root=General&path=About

Accessibility — prefs:root=General&path=ACCESSIBILITY

Airplane Mode On — prefs:root=AIRPLANE_MODE

Auto-Lock — prefs:root=General&path=AUTOLOCK

Brightness — prefs:root=Brightness

Bluetooth — prefs:root=General&path=Bluetooth

Date & Time — prefs:root=General&path=DATE_AND_TIME

FaceTime — prefs:root=FACETIME

General — prefs:root=General

Keyboard — prefs:root=General&path=Keyboard

iCloud — prefs:root=CASTLE

iCloud Storage & Backup — prefs:root=CASTLE&path=STORAGE_AND_BACKUP

International — prefs:root=General&path=INTERNATIONAL

Location Services — prefs:root=LOCATION_SERVICES

Music — prefs:root=MUSIC

Music Equalizer — prefs:root=MUSIC&path=EQ

Music Volume Limit — prefs:root=MUSIC&path=VolumeLimit

Network — prefs:root=General&path=Network

Nike + iPod — prefs:root=NIKE_PLUS_IPOD

Notes — prefs:root=NOTES

Notification — prefs:root=NOTIFICATIONS_ID

//

@"prefs:root=NOTIFICATIONS_ID&path=应用的boundleId"

Phone — prefs:root=Phone

Photos — prefs:root=Photos

Profile — prefs:root=General&path=ManagedConfigurationList

Reset — prefs:root=General&path=Reset

Safari — prefs:root=Safari

Siri — prefs:root=General&path=Assistant

Sounds — prefs:root=Sounds

Software Update — prefs:root=General&path=SOFTWARE_UPDATE_LINK

Store — prefs:root=STORE

Twitter — prefs:root=TWITTER

Usage — prefs:root=General&path=USAGE

VPN — prefs:root=General&path=Network/VPN

Wallpaper — prefs:root=Wallpaper

Wi-Fi — prefs:root=WIFI

文／小球hy（简书作者）
原文链接：http://www.jianshu.com/p/1fb3f60b689a
著作权归作者所有，转载请联系作者获得授权，并标注“简书作者”。