Exporting larger files

[Guser979]

In my app, I tried to export a 400 MB file using "savebytestouri," and the file was 0 bytes. When the file was 200 MB, it was written normally. This is due to the limitation of the array used: TDynArrayOfJByte.

Solution:
1) Create an additional "AppendBytesToUri" method.
2) Use a function in your app that dynamically adjusts the array size until the entire file is written to user-accessible storage.



1)
Add code in “androidwidget.pas”:

Code: Pascal  [Select][+][-]

1. procedure AppendBytesToUri(_bytes: TDynArrayOfJByte; _toTreeUri: jObject);
2. procedure jForm_AppendBytesToUri(env: PJNIEnv; _jform: JObject; _bytes: TDynArrayOfJByte; _toUri: jObject);
3.  
4.  
5. procedure  AppendBytesToUri(_bytes: TDynArrayOfJByte; _toTreeUri: jObject);
6. begin
7.   //in designing component state: set value here...
8.   if FInitialized then
9.      jForm_AppendBytesToUri(FjEnv, FjObject, _bytes ,_toTreeUri);
10. end;
11.  
12. procedure jForm_AppendBytesToUri(env: PJNIEnv; _jform: JObject; _bytes: TDynArrayOfJByte; _toUri: jObject);
13. var
14.   jParams: array[0..1] of jValue;
15.   jMethod: jMethodID = nil;
16.   jCls: jClass = nil;
17.   byteArray: jByteArray;
18.   len: SizeInt;
19. label
20.   _exceptionOcurred;
21. begin
22.   jCls := env^.GetObjectClass(env, _jform);
23.   if jCls = nil then goto _exceptionOcurred;
24.  
25.   jMethod := env^.GetMethodID(env, jCls, 'AppendBytesToUri', '([BLandroid/net/Uri;)V');
26.   if jMethod = nil then goto _exceptionOcurred;
27.  
28.   len := Length(_bytes);
29.   byteArray := env^.NewByteArray(env, len);
30.   env^.SetByteArrayRegion(env, byteArray, 0 , len, @_bytes[0]);
31.  
32.   jParams[0].l := byteArray;
33.   jParams[1].l := _toUri;
34.  
35.   env^.CallVoidMethodA(env, _jform, jMethod, @jParams);
36.   env^.DeleteLocalRef(env, jParams[0].l);
37.   env^.DeleteLocalRef(env, jCls);
38.  
39.   _exceptionOcurred: jni_ExceptionOccurred(env);
40. end;
41.  
42.  
43.  

Add code in “jForm.java”:

Code: Pascal  [Select][+][-]

1. public void AppendBytesToUri(byte[] _bytes, Uri _toTreeUri) {
2.     OutputStream out = null;
3.     try {
4.         out = controls.activity.getContentResolver().openOutputStream(_toTreeUri, "wa"); //   append mode
5.         out.write(_bytes);
6.         out.flush();
7.     } catch (FileNotFoundException e) {
8.         e.printStackTrace();
9.     } catch (IOException e) {
10.         e.printStackTrace();
11.     } finally {
12.         try {
13.             if (out != null) out.close();
14.         } catch (IOException e) {
15.             e.printStackTrace();
16.         }
17.     }
18. }      
19.  
20.  
21.  

2)
Usage example:

Code: Pascal  [Select][+][-]

1.  
2. //In this  example  the app registers several photos that need to be exported.
3.  
4.  
5.  
6. // procedure export(arqname:string);
7. // procedure AndroidModule1ActivityResult(Sender: TObject;requestCode: integer; resultCode: TAndroidResult; intentData: jObject);
8. // function  StreamFileSmart(const FilePath: string; const Uri: jObject): Boolean;  
9.  
10.  
11.  
12. //  var  zipnam :string; //Global var  
13.  
14.  
15. // call export
16. // zipnam:='fotos.zip' ; export (zipnam);
17.  
18.  
19.  
20.  
21.  // Here a .zip file  (zipnam) is created with all the photos registered in the app and we invoke the file creation to obtain the uri
22.  procedure TAndroidModule1.export(arqname:string);
23.    
24.   var zip: TZipper;i: Integer;relativefn,tmp: String;
25.    
26.  begin
27.    
28.    L := TStringList.Create;FindAllFiles(L,GetEnvironmentDirectoryPath(dirDCIM), '*.jpg', true);
29.                
30.    zip := TZipper.Create;
31.  
32.  
33.   try
34.     zip.Filename := arqname;
35.  
36.     try
37.  
38.       for i:=0 to  L.Count-1    do begin
39.          
40.                   if L[i] ='' then break;
41.        
42.                   relativefn := CreateRelativePath(L[i],GetEnvironmentDirectoryPath(dirDownloads));
43.  
44.           zip.Entries.AddFileEntry ( SysToUTF8(L[i]),extractfilename( l[i] ));
45.       end;
46.  
47.     finally
48.       L.Free;
49.     end;
50.  
51.     zip.SaveToFile(GetEnvironmentDirectoryPath(dirDownloads)+'/'+arqname);
52.  
53.     Self.RequestCreateFile(Self.GetEnvironmentDirectoryPath(dirDownloads),'application/zip',arqname, 114);
54.  
55.     finally
56.     zip.Free;
57.   end;
58.  end;                        
59.  
60.  
61. // This is where we get the .zip file's uri and call the function to write the content.
62.  procedure TAndroidModule1.AndroidModule1ActivityResult(Sender: TObject;
63.   requestCode: integer; resultCode: TAndroidResult; intentData: jObject);
64.  
65.  
66.  begin
67.         treeUri:= IntentManager1.GetDataUri(intentData);
68.  
69.     if requestCode = 114 then  //create file
70.      begin
71.  
72.       Self.CopyFile(Self.GetEnvironmentDirectoryPath(dirDatabase)+'/'+zipnam,Self.GetEnvironmentDirectoryPath(dirDownloads)+'/'+zipnam );                                      
73.       StreamFileSmart(GetEnvironmentDirectoryPath(dirDownloads)+'/'+zipnam,treeUri);
74.         end;
75.  
76.   end;
77.  
78.  
79. // Here's the function that uses AppendBytesToUri for any file size. It sends a maximum of 200 MB and adjusts the array size if necessary.
80. function  TAndroidModule1.StreamFileSmart(const FilePath: string; const Uri: jObject): Boolean;
81. const
82.   MAX_CHUNK = 200 * 1024 * 1024;
83. var
84.   fs: TFileStream;
85.   buffer: array of byte;
86.   jBuffer: TDynArrayOfJByte;
87.   bytesRead, chunkSize: Integer;
88. begin
89.   Result := False;
90.  
91.   if not FileExists(FilePath) then Exit;
92.  
93.   try
94.     fs := TFileStream.Create(FilePath, fmOpenRead or fmShareDenyWrite);
95.     try
96.       if fs.Size <= MAX_CHUNK then
97.         chunkSize := fs.Size
98.       else
99.         chunkSize := MAX_CHUNK;
100.  
101.       SetLength(buffer, chunkSize);
102.       SetLength(jBuffer, chunkSize);
103.  
104.       repeat
105.         bytesRead := fs.Read(buffer[0], chunkSize);
106.         if bytesRead > 0 then
107.         begin
108.            
109.           Move(buffer[0], jBuffer[0], bytesRead);
110.           SetLength(jBuffer, bytesRead);
111.  
112.            
113.        AppendBytesToUri( jBuffer, Uri);
114.         end;
115.       until bytesRead < chunkSize;
116.  
117.       Result := True;
118.     finally
119.       fs.Free;
120.     end;
121.   except
122.     on E: Exception do
123.     begin
124.       //  log error ou message
125.        
126.       Result := False;
127.     end;
128.   end;
129. end;                      
130.  
131.  
132.  

// Credits : jmpessoa, neuro , ChatGpt