Java tutorial
package edu.mit.mobile.android.livingpostcards; /* * Copyright (C) 2012-2013 MIT Mobile Experience Lab * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation version 2 * of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ import android.app.AlertDialog; import android.app.Dialog; import android.content.DialogInterface; import android.content.DialogInterface.OnClickListener; import android.net.Uri; import android.os.Bundle; import android.support.v4.app.DialogFragment; import android.util.Log; import android.widget.Toast; import edu.mit.mobile.android.content.ProviderUtils; import edu.mit.mobile.android.flipr.R; import edu.mit.mobile.android.locast.data.JsonSyncableItem; import edu.mit.mobile.android.locast.sync.LocastSyncService; /** * <p> * A delete confirmation dialog that can delete any JsonSyncableItem. * </p> * * <p> * To use, call {@link #newInstance(Uri, CharSequence)} with the uri of the item you wish to delete * as well as the message to display when prompting the user to delete the item. * </p> * * @author <a href="mailto:spomeroy@mit.edu">Steve Pomeroy</a> * */ public class DeleteDialogFragment extends DialogFragment implements OnClickListener { private static final String ARG_ITEM_URI = "uri"; private static final String ARG_MESSAGE = "message"; private static final String ARG_TITLE = "title"; private static final String TAG = DeleteDialogFragment.class.getSimpleName(); private OnDeleteListener mOnDeleteListener; private Uri mItem; private CharSequence mMessage; private CharSequence mTitle; public static DeleteDialogFragment newInstance(Uri item, CharSequence title, CharSequence message) { final DeleteDialogFragment f = new DeleteDialogFragment(); final Bundle args = new Bundle(); args.putParcelable(ARG_ITEM_URI, item); args.putCharSequence(ARG_TITLE, title); args.putCharSequence(ARG_MESSAGE, message); f.setArguments(args); return f; } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); final Bundle args = getArguments(); mMessage = args.getCharSequence(ARG_MESSAGE); mTitle = args.getCharSequence(ARG_TITLE); final Uri item = args.getParcelable(ARG_ITEM_URI); mItem = item; final String type = getActivity().getContentResolver().getType(mItem); if (type == null || !type.startsWith(ProviderUtils.TYPE_ITEM_PREFIX)) { Toast.makeText(getActivity().getApplicationContext(), "Cannot handle the requested content type", Toast.LENGTH_LONG).show(); dismiss(); return; } } @Override public void onDestroy() { super.onDestroy(); mOnDeleteListener = null; } @Override public Dialog onCreateDialog(Bundle savedInstanceState) { return new AlertDialog.Builder(getActivity()).setIcon(R.drawable.ic_launcher).setTitle(mTitle) .setPositiveButton(R.string.delete, this).setMessage(mMessage) .setNegativeButton(android.R.string.cancel, this).setCancelable(true).create(); } public void registerOnDeleteListener(OnDeleteListener listener) { mOnDeleteListener = listener; } public void unregisterOnDeleteListener(OnDeleteListener listener) { mOnDeleteListener = null; } @Override public void onClick(DialogInterface dialog, int which) { switch (which) { case AlertDialog.BUTTON_POSITIVE: { final int count = JsonSyncableItem.markDeleted(getActivity().getContentResolver(), mItem, true, null, null); dialog.dismiss(); if (count >= 1) { LocastSyncService.startSync(getActivity(), mItem, true); } else { Log.w(TAG, "Failed to delete " + mItem + ". Count from markDeleted() was " + count); } if (mOnDeleteListener != null) { mOnDeleteListener.onDelete(mItem, count >= 1); // it should only ever be 1, // but... } } break; case AlertDialog.BUTTON_NEGATIVE: dialog.cancel(); if (mOnDeleteListener != null) { mOnDeleteListener.onDelete(mItem, false); } break; } } public static interface OnDeleteListener { public void onDelete(Uri item, boolean deleted); } }