Android file chooser is not opening from WebView in Lollipop nor Marshmallow

Question

I'm developing an app, that uses a WebView to access some logic. The logic, has a part where the user can upload a picture, but, I can't seem to find a way for the app to do so.
The code I'm using as example is in this link.

As you will see, a custom Intent is set from the WebChromeClient, however, the file chooser does not open at all. Code:

public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType){  

                // Update message
                mUploadMessage = uploadMsg;

                try{    

                    // Create AndroidExampleFolder at sdcard

                    File imageStorageDir = new File(
                                           Environment.getExternalStoragePublicDirectory(
                                           Environment.DIRECTORY_PICTURES)
                                           , "AndroidExampleFolder");

                    if (!imageStorageDir.exists()) {
                        // Create AndroidExampleFolder at sdcard
                        imageStorageDir.mkdirs();
                    }

                    // Create camera captured image file path and name 
                    File file = new File(
                                    imageStorageDir + File.separator + "IMG_"
                                    + String.valueOf(System.currentTimeMillis()) 
                                    + ".jpg");

                    mCapturedImageURI = Uri.fromFile(file); 

                    // Camera capture image intent
                    final Intent captureIntent = new Intent(
                                                  android.provider.MediaStore.ACTION_IMAGE_CAPTURE);

                    captureIntent.putExtra(MediaStore.EXTRA_OUTPUT, mCapturedImageURI);

                    Intent i = new Intent(Intent.ACTION_GET_CONTENT); 
                    i.addCategory(Intent.CATEGORY_OPENABLE);
                    i.setType("image/*");

                    // Create file chooser intent
                    Intent chooserIntent = Intent.createChooser(i, "Image Chooser");

                    // Set camera intent to file chooser 
                    chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS
                                           , new Parcelable[] { captureIntent });

                    // On select image call onActivityResult method of activity
                    startActivityForResult(chooserIntent, FILECHOOSER_RESULTCODE);

                  }
                 catch(Exception e){
                     Toast.makeText(getBaseContext(), "Exception:"+e, 
                                Toast.LENGTH_LONG).show();
                 }

            }

Thanks in advance!
EDIT

So, after @JoxTraex enlightened me, I realized that the file chooser was not triggering because I was not overriding any methods of the WebChromeClient. Now, the file chooser is prompting, but, if a select an image, the image doesn't get uploaded.
The code I'm using for the file chooser:

@Override
            public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, FileChooserParams fileChooserParams) {
                openFileChooser(filePathCallback, "");
                return super.onShowFileChooser(webView, filePathCallback, fileChooserParams);
            }

            public void openFileChooser(ValueCallback<Uri[]> uploadMsg, String acceptType){
                // Update message
                //mUploadMessage = uploadMsg.this;
                try{
                    // Create AndroidExampleFolder at sdcard
                    File imageStorageDir = new File(
                            Environment.getExternalStoragePublicDirectory(
                                    Environment.DIRECTORY_PICTURES)
                            , "AndroidExampleFolder");

                    if (!imageStorageDir.exists()) {
                        // Create AndroidExampleFolder at sdcard
                        imageStorageDir.mkdirs();
                    }

                    // Create camera captured image file path and name
                    File file = new File(
                            imageStorageDir + File.separator + "IMG_"
                                    + String.valueOf(System.currentTimeMillis())
                                    + ".jpg");

                    mCapturedImageURI = Uri.fromFile(file);

                    // Camera capture image intent
                    final Intent captureIntent = new Intent(
                            android.provider.MediaStore.ACTION_IMAGE_CAPTURE);

                    captureIntent.putExtra(MediaStore.EXTRA_OUTPUT, mCapturedImageURI);

                    Intent i = new Intent(Intent.ACTION_GET_CONTENT);
                    i.addCategory(Intent.CATEGORY_OPENABLE);
                    i.setType("image/*");

                    // Create file chooser intent
                    Intent chooserIntent = Intent.createChooser(i, "Image Chooser");

                    // Set camera intent to file chooser
                    chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS
                            , new Parcelable[] { captureIntent });

                    // On select image call onActivityResult method of activity
                    startActivityForResult(chooserIntent, FILECHOOSER_RESULTCODE);

                }
                catch(Exception e){
                    Toast.makeText(getBaseContext(), "Exception:"+e,
                            Toast.LENGTH_LONG).show();
                }

            }

Thanks in advance!

Answer 1

Well, after struggling with some listeners, I found a code that resolved my situation. Nevertheless, thanks to @JoxTraex and this dude.

Answer 2

The accepted answer is correct, but I will post my code if it helps anyone. I used the code below, which is to be added inside webChrome class.

public boolean onShowFileChooser(WebView view, ValueCallback<Uri[]> uploadMsg, WebChromeClient.FileChooserParams fileChooserParams) {
            mFilePathCallback = uploadMsg;
            Intent i = new Intent(Intent.ACTION_GET_CONTENT);
            i.addCategory(Intent.CATEGORY_OPENABLE);
            i.setType("image/*");
            startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);
            return true;
        }

And use the code in onActivityResult

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        if (requestCode != FILECHOOSER_RESULTCODE || mFilePathCallback == null) {
            super.onActivityResult(requestCode, resultCode, intent);
            return;
        }
        Uri[] results = null;
        // Check that the response is a good one
        if (resultCode == Activity.RESULT_OK) {
                String dataString = intent.getDataString();
                if (dataString != null) {
                    results = new Uri[]{Uri.parse(dataString)};
            }
        }
        mFilePathCallback.onReceiveValue(results);
        mFilePathCallback = null;
    }

You will also need runtime permissions for Marshmallow and up. This code will work fine in Lollipop. You have to add conditions for other android versions as well to make it work on other versions