I had some problems

It looks like there are a few things here, so I'll try to address them each:

First, note that you don't need to register a redirect URI of "https://db-ht5jlmr230u0823" on the Dropbox web site. The SDK and API will handle that for you. You just need to register your URL scheme of "db-ht5jlmr230u0823" as instructed.

The 'account_info.write' scope is only necessary if you need to use the setProfilePhoto method.

You can use the createFolder method to create a folder, but it's better to use the newer createFolderV2. You mentioned "result is nil", so that would indicate an error occurred. You should make sure you also check the routeError and networkError variables for errors.

Your reference to "entries is null,and hasMore is no" sounds like you're referring to the result of a listFolder call. If you called that with the path for a brand new folder, that would be expected, since by default new folders are empty.

The 'expired_access_token' error indicates that the short-lived access token you're using has expired. You can find more information on how this works in the OAuth Guide.

The 'DBSDKReachability' line is just for reference and can be ignored.

The 'canOpenURL: failed for URL' lines can also be ignored. Those indicate that the official Dropbox iOS app is not installed. The SDK will instead use the built-in flow to process the app authorization. The "Success! User is logged into Dropbox." line then does seem to indicate that the authorization flow did work.

The "Folder is large enough" line seems to be some of your own logging indicating that you need to call back to listFolderContinue. Please refer to the listFolder and listFolderContinue documentation for information on using those.

Hello,

         I'm running tests on the simulator. when I used createFolder,  result is nil,routeError is nil,networkError is error.print log:

<DBFILESCreateFolderError: 0x600003a771c0>

DropboxHttpError[{

    ErrorContent = "path/conflict/folder/..";

    RequestId = ebdf556d699e4888a0808509712d1287;

    StatusCode = 409;

    UserMessage = nil;

}];

 and when i used createFolderV2,result is nil,routeError is DBFILESCreateFolderError *0x0000600003a7e000,print log:

<DBFILESCreateFolderError: 0x600003a7e000>

DropboxHttpError[{

    ErrorContent = "path/conflict/folder/.";

    RequestId = 2479a33598ae4e909ac96a3032e4f606;

    StatusCode = 409;

    UserMessage = nil;

}];

A 'path/conflict/folder' error like this indicates "There’s a folder in the way". That is, the folder could not be created because there's already a folder at the specified path. 

Hello,

     A 'path/conflict/folder' error like this indicates "There’s a folder in the way". That is, the folder could not be created because there's already a folder at the specified path.  How can I see the data in my cloud disk, or how to obtain the data in the cloud disk, I want to know how to display the data stored in my cloud disk on my app.  

If you want to manually browse the contents of your own Dropbox account, you can do so using the standard Dropbox products, such as the Dropbox web site at https://www.dropbox.com/home .

To list the contents of the connected account in your own app, you can use the listFolder and listFolderContinue methods. And to download the contents of a file, you can use the download methods.