不叨叨直接搞忍些。

1.首先是在info.plist文件配置一下（增加兩個key）：

Supports opening documents in place

Application supports iTunes file sharing

2.因為自己項目的[UINavigationBar appearance]的字體等設置的白色 所以導致present到UIDocumentPickerViewController時 雖然點右上角有反應但看不到按鈕（因為UIDocumentPickerViewController的導航欄也是白色的）∈母停基于此需要新建一個繼承于UIDocumentPickerViewController的子類DocumentViewController辨泳。

#import <UIKit/UIKit.h>

@interface DocumentViewController : UIDocumentPickerViewController

@end

#import "DocumentViewController.h"

@interface DocumentViewController ()

@end

@implementation DocumentViewController

-(void)viewWillAppear:(BOOL)animated {

    [super viewWillAppear:animated];
    //跟隨系統(tǒng)顏色
    [UINavigationBar appearance].tintColor = self.view.tintColor;
    [[UINavigationBar appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName:self.view.tintColor}];
}

- (void)viewWillDisappear:(BOOL)animated {

    [super viewWillDisappear:animated];
    //跟隨app顏色
    [[UINavigationBar appearance] setTintColor:[UIColor whiteColor]];
    [[UINavigationBar appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName:[UIColor whiteColor]}];
}

@end

當然你也可以像微信那樣在子類中完成自己的（原諒色）風格定制蓖扑。

3.接下來就簡單了 我只需要上傳pdf 所以... 拿到文件data 新建一個文件夾寫到本地沙盒

#pragma mark -- 選擇文件
- (void)goSelcetPdf  {
    NSArray *documentTypes = @[@"com.adobe.pdf"];
    DocumentViewController *documentPickerViewController = [[DocumentViewController alloc] initWithDocumentTypes:documentTypes inMode:UIDocumentPickerModeOpen];
    documentPickerViewController.delegate = self;
    [self presentViewController:documentPickerViewController animated:YES completion:nil];
}

#pragma mark - UIDocumentPickerDelegate
- (void)documentPicker:(UIDocumentPickerViewController *)controller didPickDocumentsAtURLs:(nonnull NSArray<NSURL *> *)urls {
    BOOL fileUrlAuthozied = [urls.firstObject startAccessingSecurityScopedResource];
    if(fileUrlAuthozied) {
        //通過文件協(xié)調(diào)工具來得到新的文件地址唉铜，以此得到文件保護功能
        NSFileCoordinator *fileCoordinator = [[NSFileCoordinator alloc] init];
        NSError*error;     
      [fileCoordinatorcoordinateReadingItemAtURL:urls.firstObject options:0 error:&error byAccessor:^(NSURL *newURL) {
            //讀取文件
            fileName= [newURLlastPathComponent];
            NSError*error =nil;
            NSData *fileData = [NSData dataWithContentsOfURL:newURL options:NSDataReadingMappedIfSafe error:&error];

            if(error) {

                //讀取出錯
            }else{
                //保存                              
                pdfData= fileData;
               NSArray*paths  =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
                NSString*path = [pathsobjectAtIndex:0];
                path = [pathstringByAppendingString:@"/YWBG"];
                if (![[NSFileManager defaultManager] fileExistsAtPath:path]) {
                    [[NSFileManager defaultManager] createDirectoryAtPath:path withIntermediateDirectories:YES attributes:nil error:nil];
                }
                pathUrl = [path stringByAppendingPathComponent:fileName];
                [pdfData writeToFile:pathUrl atomically:YES];
            }
            [self dismissViewControllerAnimated:YES completion:NULL];
        }];
        [urls.firstObject stopAccessingSecurityScopedResource];
    }else{
        //授權失敗
    }
}

水平有限 不喜來噴。律杠。潭流。