fix 'create backup' button

src/main/java/eu/siacs/conversations/ui/fragment/settings/MainSettingsFragment.java

@@ -1,33 +1,101 @@
 package eu.siacs.conversations.ui.fragment.settings;
 
+import android.Manifest;
+import android.content.Intent;
+import android.content.pm.PackageManager;
 import android.os.Build;
 import android.os.Bundle;
+import android.widget.Toast;
 
+import androidx.activity.result.ActivityResultLauncher;
+import androidx.activity.result.contract.ActivityResultContracts;
 import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
+import androidx.preference.Preference;
 import androidx.preference.PreferenceFragmentCompat;
 
+import com.google.android.material.dialog.MaterialAlertDialogBuilder;
 import com.google.common.base.Strings;
 
 import eu.siacs.conversations.BuildConfig;
 import eu.siacs.conversations.R;
+import eu.siacs.conversations.persistance.FileBackend;
+import eu.siacs.conversations.services.ExportBackupService;
 
 public class MainSettingsFragment extends PreferenceFragmentCompat {
 
+    private static final String CREATE_BACKUP = "create_backup";
+
+    private ActivityResultLauncher<String> requestStorageForBackupLauncher =
+            registerForActivityResult(
+                    new ActivityResultContracts.RequestPermission(),
+                    isGranted -> {
+                        if (isGranted) {
+                            startBackup();
+                        } else {
+                            Toast.makeText(
+                                            requireActivity(),
+                                            getString(
+                                                    R.string.no_storage_permission,
+                                                    getString(R.string.app_name)),
+                                            Toast.LENGTH_LONG)
+                                    .show();
+                        }
+                    });
+
     @Override
     public void onCreatePreferences(@Nullable Bundle savedInstanceState, @Nullable String rootKey) {
         setPreferencesFromResource(R.xml.preferences_main, rootKey);
         final var about = findPreference("about");
         final var connection = findPreference("connection");
-        if (about == null || connection == null) {
+        final var backup = findPreference(CREATE_BACKUP);
-            throw new IllegalStateException("The preference resource file is missing some preferences");
+        if (about == null || connection == null || backup == null) {
+            throw new IllegalStateException(
+                    "The preference resource file is missing some preferences");
         }
+        backup.setSummary(
+                getString(
+                        R.string.pref_create_backup_summary,
+                        FileBackend.getBackupDirectory(requireContext()).getAbsolutePath()));
+        backup.setOnPreferenceClickListener(this::onBackupPreferenceClicked);
         about.setTitle(getString(R.string.title_activity_about_x, BuildConfig.APP_NAME));
-        about.setSummary(String.format("%s %s %s (%s)", BuildConfig.APP_NAME, BuildConfig.VERSION_NAME, im.conversations.webrtc.BuildConfig.WEBRTC_VERSION, Strings.nullToEmpty(Build.DEVICE)));
+        about.setSummary(
+                String.format(
+                        "%s %s %s (%s)",
+                        BuildConfig.APP_NAME,
+                        BuildConfig.VERSION_NAME,
+                        im.conversations.webrtc.BuildConfig.WEBRTC_VERSION,
+                        Strings.nullToEmpty(Build.DEVICE)));
         if (ConnectionSettingsFragment.hideChannelDiscovery()) {
             connection.setSummary(R.string.pref_connection_summary);
         }
     }
 
+    private boolean onBackupPreferenceClicked(final Preference preference) {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU) {
+            if (ContextCompat.checkSelfPermission(
+                            requireContext(), Manifest.permission.WRITE_EXTERNAL_STORAGE)
+                    != PackageManager.PERMISSION_GRANTED) {
+                requestStorageForBackupLauncher.launch(Manifest.permission.WRITE_EXTERNAL_STORAGE);
+            } else {
+                startBackup();
+            }
+        } else {
+            startBackup();
+        }
+        return true;
+    }
+
+    private void startBackup() {
+        ContextCompat.startForegroundService(
+                requireContext(), new Intent(requireContext(), ExportBackupService.class));
+        final MaterialAlertDialogBuilder builder =
+                new MaterialAlertDialogBuilder(requireActivity());
+        builder.setMessage(R.string.backup_started_message);
+        builder.setPositiveButton(R.string.ok, null);
+        builder.create().show();
+    }
+
     @Override
     public void onStart() {
         super.onStart();