Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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 org.apache.taverna.mobile.activities; import android.annotation.TargetApi; import android.content.Context; import android.content.res.Configuration; import android.os.Build; import android.os.Bundle; import android.preference.ListPreference; import android.preference.Preference; import android.preference.PreferenceActivity; import android.preference.PreferenceFragment; import android.preference.PreferenceManager; import android.support.v4.app.NavUtils; import android.view.MenuItem; import org.apache.taverna.mobile.R; import org.apache.taverna.mobile.TavernaApplication; import org.apache.taverna.mobile.data.local.PreferencesHelper; import java.util.List; /** * A {@link PreferenceActivity} that presents a set of application settings. On * handset devices, settings are presented as a single list. On tablets, * settings are split by category, with category headers shown to the left of * the list of settings. * <p/> * See <a href="http://developer.android.com/design/patterns/settings.html"> * Android Design: Settings</a> for design guidelines and the <a * href="http://developer.android.com/guide/topics/ui/settings.html">Settings * API Guide</a> for more information on developing a Settings UI. */ public class SettingsActivity extends PreferenceActivity { /** * A preference value change listener that updates the preference's summary * to reflect its new value. */ private static Preference.OnPreferenceChangeListener sBindPreferenceSummaryToValueListener = new Preference.OnPreferenceChangeListener() { @Override public boolean onPreferenceChange(Preference preference, Object value) { String stringValue = value.toString(); if (preference instanceof ListPreference) { // For list preferences, look up the correct display value in // the preference's 'entries' list. ListPreference listPreference = (ListPreference) preference; int index = listPreference.findIndexOfValue(stringValue); // Set the summary to reflect the new value. preference.setSummary(index >= 0 ? listPreference.getEntries()[index] : null); } else { // For all other preferences, set the summary to the value's // simple string representation. if (preference.getKey().equals(PreferencesHelper.PREF_KEY_PLAYER_URL)) { new PreferencesHelper(TavernaApplication.getContext()).setUserPlayerLoggedInFlag(false); } preference.setSummary(stringValue); } return true; } }; /** * Helper method to determine if the device has an extra-large screen. For * example, 10" tablets are extra-large. */ private static boolean isXLargeTablet(Context context) { return (context.getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) >= Configuration.SCREENLAYOUT_SIZE_XLARGE; } /** * Determines whether the simplified settings UI should be shown. This is * true if the device doesn't have newer APIs like {@link PreferenceFragment}, * or the device doesn't have an extra-large screen. In these cases, a single-pane * "simplified" settings UI should be shown. */ private static boolean isSimplePreferences(Context context) { return Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB || !isXLargeTablet(context); } /** * Binds a preference's summary to its value. More specifically, when the * preference's value is changed, its summary (line of text below the * preference title) is updated to reflect the value. The summary is also * immediately updated upon calling this method. The exact display format is * dependent on the type of preference. * * @see #sBindPreferenceSummaryToValueListener */ private static void bindPreferenceSummaryToValue(Preference preference) { // Set the listener to watch for value changes. preference.setOnPreferenceChangeListener(sBindPreferenceSummaryToValueListener); // Trigger the listener immediately with the preference's // current value. sBindPreferenceSummaryToValueListener.onPreferenceChange(preference, PreferenceManager .getDefaultSharedPreferences(preference.getContext()).getString(preference.getKey(), "")); } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // setupActionBar(); } /** * Set up the {@link android.app.ActionBar}, if the API is available. */ /* @NonNull @TargetApi(Build.VERSION_CODES.HONEYCOMB) private void setupActionBar() { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) { // Show the Up button in the action bar. getActionBar().setDisplayHomeAsUpEnabled(true); } } */ @Override public boolean onOptionsItemSelected(MenuItem item) { int id = item.getItemId(); if (id == android.R.id.home) { // This ID represents the Home or Up button. In the case of this // activity, the Up button is shown. Use NavUtils to allow users // to navigate up one level in the application structure. For // more details, see the Navigation pattern on Android Design: // // http://developer.android.com/design/patterns/navigation.html#up-vs-back // // TODO: If Settings has multiple levels, Up should navigate up // that hierarchy. NavUtils.navigateUpFromSameTask(this); return true; } return super.onOptionsItemSelected(item); } @Override protected void onPostCreate(Bundle savedInstanceState) { super.onPostCreate(savedInstanceState); setupSimplePreferencesScreen(); } /** * Shows the simplified settings UI if the device configuration if the * device configuration dictates that a simplified, single-pane UI should be * shown. * Note that this is only valid for older Honeycomb and below API levels which * the app does not target. */ private void setupSimplePreferencesScreen() { //TODO remove this since the app does not need to support old API levels if (!isSimplePreferences(this)) { return; } // In the simplified UI, fragments are not used at all and we instead // use the older PreferenceActivity APIs. // Add 'general' preferences. addPreferencesFromResource(R.xml.pref_general); // Bind the summaries of EditText/List/Dialog/Ringtone preferences to // their values. When their values change, their summaries are updated // to reflect the new value, per the Android Design guidelines. //bindPreferenceSummaryToValue(findPreference("pref_server_url")); bindPreferenceSummaryToValue(findPreference("pref_player_url")); } /** * {@inheritDoc} */ @Override public boolean onIsMultiPane() { return isXLargeTablet(this) && !isSimplePreferences(this); } /** * {@inheritDoc} */ @Override @TargetApi(Build.VERSION_CODES.HONEYCOMB) public void onBuildHeaders(List<Header> target) { if (!isSimplePreferences(this)) { loadHeadersFromResource(R.xml.pref_headers, target); } } /** * This fragment shows general preferences only. It is used when the * activity is showing a two-pane settings UI. */ @TargetApi(Build.VERSION_CODES.HONEYCOMB) public static class GeneralPreferenceFragment extends PreferenceFragment { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); addPreferencesFromResource(R.xml.pref_general); // Bind the summaries of EditText/List/Dialog/Ringtone preferences // to their values. When their values change, their summaries are // updated to reflect the new value, per the Android Design // guidelines. bindPreferenceSummaryToValue(findPreference("pref_server_url")); bindPreferenceSummaryToValue(findPreference("pref_player_url")); } } }