1、首先在自己App的info.plist中註冊可用型別

    <key>CFBundleDocumentTypes</key>
    <array>
        <dict>
            <key>CFBundleTypeName</key>
            <string>com.myapp.common-data</string>
            <key>LSItemContentTypes</key>
            <array>
                <string
 
>com.microsoft.powerpoint.ppt</string>
                <string>public.item</string>
                <string>com.microsoft.word.doc</string>
                <string>com.adobe.pdf</string>
                <string>com.microsoft.excel.xls</string>
                <string
 
>public.image</string>
                <string>public.content</string>
                <string>public.composite-content</string>
                <string>public.archive</string>
                <string>public.audio</string>
                <string
 
>public.movie</string>
                <string>public.text</string>
                <string>public.data</string>
            </array>
        </dict>
    </array>

.pptx:          org.openxmlformats.presentationml.presentation
.docx:          org.openxmlformats.wordprocessingml.document
.xlsx:          org.openxmlformats.spreadsheetml.sheet

新增完後，儲存，執行程式，在QQ中選擇一個檔案，選擇用其他應用開啟，就會發現我們的app

點選之後，會調轉到自己的應用，並呼叫以下方法

- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(nullable NSString *)sourceApplication annotation:(id)annotation；

通過返回的URL可知，分享過來的檔案儲存在了Document/Inbox資料夾下

之後就可以預覽我們分享過來的檔案了。

獲取所有檔案

    NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Inbox"];

    NSFileManager *fileManager=[NSFileManager defaultManager];

    self.sourceArr = [fileManager subpathsAtPath:path];

點選進行預覽

    NSString *path = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Inbox"] stringByAppendingPathComponent:self.sourceArr[indexPath.row]];

    NSURL *url = [NSURL fileURLWithPath:path];

    QLPreviewController *vc = [QLPreviewController new];
    self.filePath = url;
    vc.delegate = self;
    vc.dataSource = self;
    [self presentViewController:vc animated:YES completion:nil];

-(NSInteger)numberOfPreviewItemsInPreviewController:(QLPreviewController *)controller{

    return 1;

}

-(id<QLPreviewItem>)previewController:(QLPreviewController *)controller previewItemAtIndex:(NSInteger)index{

    return self.filePath;

}