Choose image from gallery and camera through web view is not working in Android 6.0 Marshmallow

This will allow implementing file uploading in most versions including the marshmellow and its tested too. But doesnt allow uploading multiple files though.

If anyone has a solution for that please do suggest it

public class MainActivity extends Activity {

WebView mWebView;

private static final int INPUT_FILE_REQUEST_CODE = 1;
private static final int FILECHOOSER_RESULTCODE = 1;
private static final String TAG = MainActivity.class.getSimpleName();
private ValueCallback<Uri> mUploadMessage;
private Uri mCapturedImageURI = null;
private ValueCallback<Uri[]> mFilePathCallback;
private String mCameraPhotoPath;

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        if (requestCode != INPUT_FILE_REQUEST_CODE || mFilePathCallback == null) {
            super.onActivityResult(requestCode, resultCode, data);
            return;
        }
        Uri[] results = null;
        // Check that the response is a good one
        if (resultCode == Activity.RESULT_OK) {
            if (data == null) {
                // If there is not data, then we may have taken a photo
                if (mCameraPhotoPath != null) {
                    results = new Uri[]{Uri.parse(mCameraPhotoPath)};
                }
            } else {
                String dataString = data.getDataString();
                if (dataString != null) {
                    results = new Uri[]{Uri.parse(dataString)};
                }
            }
        }
        mFilePathCallback.onReceiveValue(results);
        mFilePathCallback = null;
    } else if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.KITKAT) {
        if (requestCode != FILECHOOSER_RESULTCODE || mUploadMessage == null) {
            super.onActivityResult(requestCode, resultCode, data);
            return;
        }
        if (requestCode == FILECHOOSER_RESULTCODE) {
            if (null == this.mUploadMessage) {
                return;
            }
            Uri result = null;
            try {
                if (resultCode != RESULT_OK) {
                    result = null;
                } else {
                    // retrieve from the private variable if the intent is null
                    result = data == null ? mCapturedImageURI : data.getData();
                }
            } catch (Exception e) {
                Toast.makeText(getApplicationContext(), "activity :" + e,
                        Toast.LENGTH_LONG).show();
            }
            mUploadMessage.onReceiveValue(result);
            mUploadMessage = null;
        }
    }
    return;
}

private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";
    File storageDir = Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES);
    File imageFile = File.createTempFile(
            imageFileName,  /* prefix */
            ".jpg",         /* suffix */
            storageDir      /* directory */
    );
    return imageFile;
}


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.activity_main);

    mWebView = (WebView) findViewById(R.id.webview);
    WebSettings webSettings = mWebView.getSettings();
    webSettings.setJavaScriptEnabled(true);

    mWebView.getSettings().setAllowFileAccess(true);
    mWebView.loadUrl("url");

           mWebView.setWebViewClient(new WebViewClient() {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return false;
        }
    });


    mWebView.setWebChromeClient(new WebChromeClient() {


        // For Android 5.0
        public boolean onShowFileChooser(WebView view, ValueCallback<Uri[]> filePath, WebChromeClient.FileChooserParams fileChooserParams) {
            // Double check that we don't have any existing callbacks
            if (mFilePathCallback != null) {
                mFilePathCallback.onReceiveValue(null);
            }
            mFilePathCallback = filePath;
            Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
                // Create the File where the photo should go
                File photoFile = null;
                try {
                    photoFile = createImageFile();
                    takePictureIntent.putExtra("PhotoPath", mCameraPhotoPath);
                } catch (IOException ex) {
                    // Error occurred while creating the File
                    Log.e(TAG, "Unable to create Image File", ex);
                }
                // Continue only if the File was successfully created
                if (photoFile != null) {
                    mCameraPhotoPath = "file:" + photoFile.getAbsolutePath();
                    takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT,
                            Uri.fromFile(photoFile));
                } else {
                    takePictureIntent = null;
                }
            }
            Intent contentSelectionIntent = new Intent(Intent.ACTION_GET_CONTENT);
            contentSelectionIntent.addCategory(Intent.CATEGORY_OPENABLE);
            contentSelectionIntent.setType("image/*");
            Intent[] intentArray;
            if (takePictureIntent != null) {
                intentArray = new Intent[]{takePictureIntent};
            } else {
                intentArray = new Intent[0];
            }
            Intent chooserIntent = new Intent(Intent.ACTION_CHOOSER);
            chooserIntent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE,true);
            chooserIntent.putExtra(Intent.EXTRA_INTENT, contentSelectionIntent);
            chooserIntent.putExtra(Intent.EXTRA_TITLE, "Image Chooser");
            chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, intentArray);
            startActivityForResult(chooserIntent, INPUT_FILE_REQUEST_CODE);
            return true;
        }
        // openFileChooser for Android 3.0+
        public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType) {
            mUploadMessage = uploadMsg;
            // Create AndroidExampleFolder at sdcard
            // 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);
        }
        // openFileChooser for Android < 3.0
        public void openFileChooser(ValueCallback<Uri> uploadMsg) {
            openFileChooser(uploadMsg, "");
        }
        //openFileChooser for other Android versions
        public void openFileChooser(ValueCallback<Uri> uploadMsg,
                                    String acceptType,
                                    String capture) {
            openFileChooser(uploadMsg, acceptType);
        }

    });


@Override
public boolean onKeyDown(int keyCode, @NonNull KeyEvent event){
    String webUrl = mWebView.getUrl();

    if(event.getAction() == KeyEvent.ACTION_DOWN){
        switch(keyCode){
            case KeyEvent.KEYCODE_BACK:
                if(mWebView.canGoBack()){
                    if((webUrl.contains("url"))){
                        new AlertDialog.Builder(this).setTitle("title")
                                .setIcon(R.mipmap.ic_launcher)
                                .setMessage("Are you sure you want to exit the app?")
                                .setPositiveButton("yes", new DialogInterface.OnClickListener() {
                                    @Override
                                    public void onClick(DialogInterface dialog, int which) {

                                        Intent intent = new Intent(Intent.ACTION_MAIN);
                                        intent.addCategory(Intent.CATEGORY_HOME);
                                        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                                        startActivity(intent);
                                        finish();
                                    }
                                }).setNegativeButton("no", null).show();
                    }
                    else
                    if((webUrl.contains("url"))){
                        Toast.makeText(this, "Press the X button.",
                                Toast.LENGTH_SHORT).show();
                    }
                    else
                    if((webUrl.contains("url")||(webUrl.contains("file:///android_asset/error_page.html")||webUrl.contains("url")))) {
                        new AlertDialog.Builder(this).setTitle("title")
                                .setIcon(R.mipmap.ic_launcher)
                                .setMessage("Are you sure you want to exit the app?")
                                .setPositiveButton("yes", new DialogInterface.OnClickListener() {
                                    @Override
                                    public void onClick(DialogInterface dialog, int which) {

                                        Intent intent = new Intent(Intent.ACTION_MAIN);
                                        intent.addCategory(Intent.CATEGORY_HOME);
                                        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                                        startActivity(intent);
                                        finish();
                                    }
                                }).setNegativeButton("no", null).show();
                    }else {
                        mWebView.goBack();
                    }
                }else {
                    new AlertDialog.Builder(this).setTitle("title")
                            .setIcon(R.mipmap.ic_launcher)
                            .setMessage("Are you sure you want to exit the app?")
                            .setPositiveButton("yes", new DialogInterface.OnClickListener() {
                                @Override
                                public void onClick(DialogInterface dialog, int which) {

                                    Intent intent = new Intent(Intent.ACTION_MAIN);
                                    intent.addCategory(Intent.CATEGORY_HOME);
                                    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                                    startActivity(intent);
                                    finish();
                                }
                            }).setNegativeButton("no", null).show();
                }
                return true;
        }
    }
    return super.onKeyDown(keyCode, event);
}
}

The example code on this page helped me achieve these results after searching for hours.

// Create Function for Image Picker

mWebView.setWebChromeClient(new WebChromeClient() {
public boolean onShowFileChooser(
        WebView webView, ValueCallback<Uri[]> filePathCallback,
        WebChromeClient.FileChooserParams fileChooserParams) {

    // Double check that we don't have any existing callbacks
    if(mFilePathCallback != null) {
        mFilePathCallback.onReceiveValue(null);
    }
    mFilePathCallback = filePathCallback;

    // Set up the take picture intent
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    if (takePictureIntent.resolveActivity(getActivity().getPackageManager()) != null) {
        // Create the File where the photo should go
        File photoFile = null;
        try {
            photoFile = createImageFile();
            takePictureIntent.putExtra("PhotoPath", mCameraPhotoPath);
        } catch (IOException ex) {
            // Error occurred while creating the File
            Log.e(TAG, "Unable to create Image File", ex);
        }

        // Continue only if the File was successfully created
        if (photoFile != null) {
            mCameraPhotoPath = "file:" + photoFile.getAbsolutePath();
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT,
                    Uri.fromFile(photoFile));
        } else {
            takePictureIntent = null;
        }
    }

    // Set up the intent to get an existing image
    Intent contentSelectionIntent = new Intent(Intent.ACTION_GET_CONTENT);
    contentSelectionIntent.addCategory(Intent.CATEGORY_OPENABLE);
    contentSelectionIntent.setType("image/*");

    // Set up the intents for the Intent chooser
    Intent[] intentArray;
    if(takePictureIntent != null) {
        intentArray = new Intent[]{takePictureIntent};
    } else {
        intentArray = new Intent[0];
    }

    Intent chooserIntent = new Intent(Intent.ACTION_CHOOSER);
    chooserIntent.putExtra(Intent.EXTRA_INTENT, contentSelectionIntent);
    chooserIntent.putExtra(Intent.EXTRA_TITLE, "Image Chooser");
    chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, intentArray);

    startActivityForResult(chooserIntent, INPUT_FILE_REQUEST_CODE);

    return true;
}
});

// Return Data to Web Page

@Override
public void onActivityResult (int requestCode, int resultCode, Intent data) {
    if(requestCode != INPUT_FILE_REQUEST_CODE || mFilePathCallback == null) {
        super.onActivityResult(requestCode, resultCode, data);
        return;
    }

    Uri[] results = null;

    // Check that the response is a good one
    if(resultCode == Activity.RESULT_OK) {
        if(data == null) {
            // If there is not data, then we may have taken a photo
            if(mCameraPhotoPath != null) {
                results = new Uri[]{Uri.parse(mCameraPhotoPath)};
            }
        } else {
            String dataString = data.getDataString();
            if (dataString != null) {
                results = new Uri[]{Uri.parse(dataString)};
            }
        }
    }

    mFilePathCallback.onReceiveValue(results);
    mFilePathCallback = null;
    return;
}