How to Enable File Upload and Download in Android Webview App | Webview App Development Series Part 19

Hi Everyone, Welcome to our mobile app developer training. As we are Converting our website to apk, in the previous tutorial we have learned How to Enable Video, Image and File Upload in Android Webview App.

And we also have learned separately How to Upload files in Android Webview App and How to Download the files in the android webview app.

Now we will combine uploading files and downloading files code together and will implement them in one Webview app project.

First of all, you need to add 3 permission for "access camera, write in external storage and Internet" in your AndroidManifest.xml file.

Code:

Then, we need to take some variables, such as:

Code:

After that, we will move to the "onCreate" method, and in the "WebChromeClient" function we will write the "onShowFileChooser" function.

Code:

 /*-- handling input[type="file"] requests for android API 21+ --*/
            public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, FileChooserParams fileChooserParams) {

                if(file_permission() && Build.VERSION.SDK_INT >= 21) {
                    file_path = filePathCallback;
                    Intent takePictureIntent = null;
                    Intent takeVideoIntent = null;

                    boolean includeVideo = false;
                    boolean includePhoto = false;

                    /*-- checking the accept parameter to determine which intent(s) to include --*/
  
                    paramCheck:
                    for (String acceptTypes : fileChooserParams.getAcceptTypes()) {
                        String[] splitTypes = acceptTypes.split(", ?+"); 
  /*-- although it's an array, it still seems to be the whole value; split it out into chunks so that we can detect multiple values --*/
                        for (String acceptType : splitTypes) {
                            switch (acceptType) {
                                case "*/*":
                                  includePhoto = true;
                                   includeVideo = true;
                                   break paramCheck;
                                case "image/*":
                                    includePhoto = true;
                                    break;
                                case "video/*":
                                    includeVideo = true;
                                    break;
                            }
                        }
                    }

                    if (fileChooserParams.getAcceptTypes().length == 0) {   
  
 /*-- no `accept` parameter was specified, allow both photo and video --*/
  
                        includePhoto = true;
                        includeVideo = true;
                    }

                    if (includePhoto) {
                        takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                        if (takePictureIntent.resolveActivity(MainActivity.this.getPackageManager()) != null) {
                            File photoFile = null;
                            try {
                                photoFile = create_image();
                                takePictureIntent.putExtra("PhotoPath", cam_file_data);
                            } catch (IOException ex) {
                                Log.e(TAG, "Image file creation failed", ex);
                            }
                            if (photoFile != null) {
                                cam_file_data = "file:" + photoFile.getAbsolutePath();
                                takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
                            } else {
                                cam_file_data = null;
                                takePictureIntent = null;
                            }
                        }
                    }

                    if (includeVideo) {
                        takeVideoIntent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
                        if (takeVideoIntent.resolveActivity(MainActivity.this.getPackageManager()) != null) {
                            File videoFile = null;
                            try {
                                videoFile = create_video();
                            } catch (IOException ex) {
                                Log.e(TAG, "Video file creation failed", ex);
                            }
                            if (videoFile != null) {
                                cam_file_data = "file:" + videoFile.getAbsolutePath();
                                takeVideoIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(videoFile));
                            } else {
                                cam_file_data = null;
                                takeVideoIntent = null;
                            }
                        }
                    }

                    Intent contentSelectionIntent = new Intent(Intent.ACTION_GET_CONTENT);
                    contentSelectionIntent.addCategory(Intent.CATEGORY_OPENABLE);
                   contentSelectionIntent.setType(file_type);

  
  if (multiple_files) {
                        contentSelectionIntent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
                    }

                    Intent[] intentArray;
                    if (takePictureIntent != null && takeVideoIntent != null) {
                        intentArray = new Intent[]{takePictureIntent, takeVideoIntent};
                    } else if (takePictureIntent != null) {
                        intentArray = new Intent[]{takePictureIntent};
                    } else if (takeVideoIntent != null) {
                        intentArray = new Intent[]{takeVideoIntent};
                    } else {
                        intentArray = new Intent[0];
                    }

                    Intent chooserIntent = new Intent(Intent.ACTION_CHOOSER);
                    chooserIntent.putExtra(Intent.EXTRA_INTENT, contentSelectionIntent);
                    chooserIntent.putExtra(Intent.EXTRA_TITLE, "File chooser");
                    chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, intentArray);
                    startActivityForResult(chooserIntent, file_req_code);
                    return true;
                } else {
                    return false;
                }
            }

Now we will write code for Downloading any files in Android Webview App. First, we will write a function for file saving permission to your device.

Code:

And then we will write code for allowing download file in the Webview app.

Code:

  webView.setDownloadListener(new DownloadListener() {
            @Override
            public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimeType, long contentLength) {

                DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
                request.setMimeType(mimeType);
                String cookies = CookieManager.getInstance().getCookie(url);
                request.addRequestHeader("cookie",cookies);
                request.addRequestHeader("User-Agent",userAgent);
                request.setDescription("Downloading file....");
                request.setTitle(URLUtil.guessFileName(url,contentDisposition,mimeType));
                request.allowScanningByMediaScanner();
                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS,URLUtil.guessFileName(url, contentDisposition, mimeType));
                DownloadManager dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
                dm.enqueue(request);
                Toast.makeText(getApplicationContext(),"Downloading File",Toast.LENGTH_SHORT).show();


            }
        });

We have finished the coding within the onCreate method, Now we will write several functions outside of the onCreate method.

Code:

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent intent){
        super.onActivityResult(requestCode, resultCode, intent);
        if(Build.VERSION.SDK_INT >= 21){
            Uri[] results = null;

            /*-- if file request cancelled; exited camera. we need to send null value to make future attempts workable --*/
            if (resultCode == Activity.RESULT_CANCELED) {
                file_path.onReceiveValue(null);
                return;
            }

            /*-- continue if response is positive --*/
            if(resultCode== Activity.RESULT_OK){
                if(null == file_path){
                    return;
                }
                ClipData clipData;
                String stringData;

                try {
                    clipData = intent.getClipData();
                    stringData = intent.getDataString();
                }catch (Exception e){
                    clipData = null;
                    stringData = null;
                }
                if (clipData == null && stringData == null && cam_file_data != null) {
                    results = new Uri[]{Uri.parse(cam_file_data)};
                }else{
                    if (clipData != null) { 
                        final int numSelectedFiles = clipData.getItemCount();
                        results = new Uri[numSelectedFiles];
                        for (int i = 0; i < clipData.getItemCount(); i++) {
                            results[i] = clipData.getItemAt(i).getUri();
                        }
                    } else {
                        try {
                            Bitmap cam_photo = (Bitmap) intent.getExtras().get("data");
                            ByteArrayOutputStream bytes = new ByteArrayOutputStream();
                            cam_photo.compress(Bitmap.CompressFormat.JPEG, 100, bytes);
                            stringData = MediaStore.Images.Media.insertImage(this.getContentResolver(), cam_photo, null, null);
                        }catch (Exception ignored){}

                        results = new Uri[]{Uri.parse(stringData)};
                    }
                }
            }

            file_path.onReceiveValue(results);
            file_path = null;
        }else{
            if(requestCode == file_req_code){
                if(null == file_data) return;
                Uri result = intent == null || resultCode != RESULT_OK ? null : intent.getData();
                file_data.onReceiveValue(result);
                file_data = null;
            }
        }
    }


    @Override
    public void onConfigurationChanged(Configuration newConfig){
        super.onConfigurationChanged(newConfig);
    } 
                                                                    
   public boolean file_permission(){
        if(Build.VERSION.SDK_INT >=23 && (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED || ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)) {
            ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.CAMERA}, 1);
            return false;
        }else{
            return true;
        }
    }

  
    private File create_image() throws IOException{
        @SuppressLint("SimpleDateFormat") String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        String imageFileName = "img_"+timeStamp+"_";
        File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
        return File.createTempFile(imageFileName,".jpg",storageDir);
    }

    private File create_video() throws IOException {
        @SuppressLint("SimpleDateFormat")
        String file_name    = new SimpleDateFormat("yyyy_mm_ss").format(new Date());
        String new_name     = "file_"+file_name+"_";
        File sd_directory   = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
        return File.createTempFile(new_name, ".3gp", sd_directory);
    }

That's it, we have finished coding for Uploading and downloading files in the Android webview app. Let's run the project and test.

As you can see in the above picture, Downloading any file and uploading any type of file in Webview App is working perfectly. See you in the next tutorial.

1 comment:

Erberth-LópezNovember 20, 2021 at 10:17 PM
Hi, everything you have taught us about uploading and downloading files works perfectly 10/10, but I would like you to show us how to do practically the same within a fragment and not in an Activity. Since I could not and I am new to this :(
Thank you in advance :3