add support for runtime-permissions (fix needed)

app/src/main/java/com/keylesspalace/tusky/ViewMediaFragment.java

@@ -15,15 +15,23 @@
 
 package com.keylesspalace.tusky;
 
+import android.*;
 import android.app.AlertDialog;
 import android.app.DownloadManager;
 import android.content.Context;
 import android.content.DialogInterface;
+import android.content.pm.PackageManager;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Bundle;
 import android.os.Environment;
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.support.annotation.StringRes;
+import android.support.design.widget.Snackbar;
+import android.support.v13.app.ActivityCompat;
 import android.support.v4.app.DialogFragment;
+import android.support.v4.content.ContextCompat;
 import android.view.LayoutInflater;
 import android.view.MotionEvent;
 import android.view.View;
@@ -34,6 +42,7 @@ import com.squareup.picasso.Callback;
 import com.squareup.picasso.Picasso;
 
 import java.io.File;
+import java.security.Permission;
 
 import butterknife.BindView;
 import butterknife.ButterKnife;
@@ -44,6 +53,9 @@ public class ViewMediaFragment extends DialogFragment {
 
     private PhotoViewAttacher attacher;
     private DownloadManager downloadManager;
+
+    private static final int PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE = 1;
+
     @BindView(R.id.view_media_image) PhotoView photoView;
 
     public static ViewMediaFragment newInstance(String url) {
@@ -118,19 +130,7 @@ public class ViewMediaFragment extends DialogFragment {
                             public void onClick(DialogInterface dialog, int which) {
                                 dialog.dismiss();
 
-                                String url = getArguments().getString("url");
-                                Uri uri = Uri.parse(url);
-
-                                String filename = new File(url).getName();
-
-                                downloadManager = (DownloadManager) getContext().getSystemService(Context.DOWNLOAD_SERVICE);
-
-                                DownloadManager.Request request = new DownloadManager.Request(uri);
-                                request.allowScanningByMediaScanner();
-                                request.setDestinationInExternalPublicDir(Environment.DIRECTORY_PICTURES, getString(R.string.app_name) + "/" + filename);
-
-                                downloadManager.enqueue(request);
-                                System.out.println(url);
+                                downloadImage();
                             }
                         });
                 downloadDialog.show();
@@ -160,4 +160,73 @@ public class ViewMediaFragment extends DialogFragment {
         attacher.cleanup();
         super.onDestroyView();
     }
+
+    /**
+     * Check permissions and download the thing at getArguments().getString("url") as image, listed in the systems gallery.
+     * This works in general, but when the permission is granted at runtime, the download button ha to be pressed again (see comment further down)
+     */
+    private void downloadImage(){
+
+        //Permission stuff
+
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN &&
+                ContextCompat.checkSelfPermission(this.getContext(), android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
+                        != PackageManager.PERMISSION_GRANTED) {
+            android.support.v4.app.ActivityCompat.requestPermissions(getActivity(),
+                    new String[] { android.Manifest.permission.WRITE_EXTERNAL_STORAGE },
+                    PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE);
+        } else {
+
+
+            //download stuff
+            String url = getArguments().getString("url");
+            Uri uri = Uri.parse(url);
+
+            String filename = new File(url).getName();
+
+            downloadManager = (DownloadManager) getContext().getSystemService(Context.DOWNLOAD_SERVICE);
+
+            DownloadManager.Request request = new DownloadManager.Request(uri);
+            request.allowScanningByMediaScanner();
+            request.setDestinationInExternalPublicDir(Environment.DIRECTORY_PICTURES, getString(R.string.app_name) + "/" + filename);
+
+            downloadManager.enqueue(request);
+        }
+    }
+
+    /*
+     * took this from ComposeActivity.java (Media upload) to handle permission requests.
+     * However, onRequestPermissionResult seems not to be called.
+     */
+    @Override
+    public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[],
+                                           @NonNull int[] grantResults) {
+        System.out.println("Requestcode: " + requestCode);
+        switch (requestCode) {
+            case PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE: {
+                if (grantResults.length > 0
+                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
+                    downloadImage();
+                } else {
+                    System.out.println("not granted\n");
+                    doErrorDialog(R.string.error_media_download_permission, R.string.action_retry,
+                            new View.OnClickListener() {
+                                @Override
+                                public void onClick(View v) {
+                                    downloadImage();
+                                }
+                            });
+                }
+                break;
+            }
+        }
+    }
+
+    private void doErrorDialog(@StringRes int descriptionId, @StringRes int actionId,
+                               View.OnClickListener listener) {
+        Snackbar bar = Snackbar.make(getActivity().findViewById(R.id.view_media_image), getString(descriptionId),
+                Snackbar.LENGTH_SHORT);
+        bar.setAction(actionId, listener);
+        bar.show();
+    }
 }

app/src/main/res/values-de/strings.xml

@@ -122,5 +122,6 @@
     <string name="error_no_web_browser_found">Kein Webbrowser gefunden.</string>
     <string name="error_retrieving_oauth_token">Es konnte kein Login-Token abgerufen werden.</string>
     <string name="dialog_download_image">Herunterladen</string>
+    <string name="error_media_download_permission">Eine Berechtigung wird zum Speichern des Mediums benötigt.</string>
 
 </resources>

app/src/main/res/values/strings.xml

@@ -12,6 +12,8 @@
     <string name="error_media_upload_type">That type of file cannot be uploaded.</string>
     <string name="error_media_upload_opening">That file could not be opened.</string>
     <string name="error_media_upload_permission">Permission to read media is required.</string>
+    <string name="error_media_download_permission">Permission to store media is required.</string>
+
     <string name="error_media_upload_image_or_video">Images and videos cannot both be attached to the same status.</string>
     <string name="error_media_upload_sending">The upload failed.</string>
     <string name="error_report_too_few_statuses">At least one status must be reported.</string>