Java tutorial
/* * Copyright 2013 i'm SpA * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package it.imwatch.nfclottery.dialogs; import android.app.Activity; import android.app.AlertDialog; import android.app.Dialog; import android.support.v4.app.DialogFragment; import android.content.ContentResolver; import android.content.DialogInterface; import android.os.Bundle; import android.util.Log; import android.widget.Toast; import de.keyboardsurfer.android.widget.crouton.Style; import it.imwatch.nfclottery.MainActivity; import it.imwatch.nfclottery.R; import it.imwatch.nfclottery.data.provider.NFCMLContent; import static it.imwatch.nfclottery.Const.*; /** * A dialog that can start a DB clearing operation, after * asking for confirmation to the user. */ public class ClearDBAlertDialog extends DialogFragment { private static final String TAG = ClearDBAlertDialog.class.getSimpleName(); @Override public Dialog onCreateDialog(Bundle savedInstanceState) { // Use the Builder class for convenient dialog construction final Activity activity = getActivity(); if (activity == null) { Log.e(TAG, "Not attached to Activity: cannot build dialog"); return null; } AlertDialog.Builder builder = new AlertDialog.Builder(activity); builder.setTitle(R.string.action_clear_db).setMessage(R.string.dialog_clear_db_message) .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { clearDB(); } }).setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { final Dialog thisDialog = ClearDBAlertDialog.this.getDialog(); if (thisDialog != null) { thisDialog.cancel(); } else { Log.w(TAG, "Can't get the Dialog instance."); } } }); // Create the AlertDialog object and return it return builder.create(); } /** * Clears the database. */ private void clearDB() { final Activity activity = getActivity(); if (activity == null) { Log.e(TAG, "Not attached to Activity: cannot clear DB"); return; } ContentResolver cr = activity.getContentResolver(); cr.delete(NFCMLContent.Geeks.CONTENT_URI, null, null); if (activity instanceof MainActivity) { final MainActivity mainActivity = (MainActivity) activity; mainActivity.showCroutonNao(mainActivity.getString(R.string.info_db_cleared), Style.INFO); mainActivity.updateParticipantsCount(); } else { Log.e(TAG, "The parent Activity is not MainActivity! Wat is this I don't even"); if (DEBUG) Log.d(TAG, "Activity class: " + activity.getLocalClassName()); Toast.makeText(activity, activity.getString(R.string.clear_db_failed_wrong_parent), Toast.LENGTH_SHORT) .show(); } } }