Java tutorial
// Copyright 2015 The Project Buendia Authors // // 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 distrib- // uted 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 // specific language governing permissions and limitations under the License. package org.projectbuendia.client.ui; import android.annotation.TargetApi; import android.content.Context; import android.content.SharedPreferences; import android.content.res.Configuration; import android.os.Build; import android.os.Bundle; 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.projectbuendia.client.R; 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 { /** * Controls whether to always show the simplified UI, where settings are * arranged in a single list without a left navigation panel. */ private static final boolean ALWAYS_SIMPLE_PREFS = false; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setupActionBar(); } @Override protected boolean isValidFragment(String fragmentName) { return true; } /** Set up the {@link android.app.ActionBar}, if the API is available. */ @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 dictates * that a simplified, single-pane UI should be shown. */ private void setupSimplePreferencesScreen() { if (!isSimplePreferences(this)) { return; } // The simplified UI uses the old PreferenceActivity API instead of PreferenceFragment. // Load the preference definitions. addPreferencesFromResource(R.xml.pref_general); // Show the values of preferences in their summary lines, per the Android Design guidelines. showValueAsSummary(findPreference("openmrs_root_url")); showValueAsSummary(findPreference("openmrs_user")); showValueAsSummary(findPreference("package_server_root_url")); showValueAsSummary(findPreference("apk_update_interval_secs")); } @Override public boolean onIsMultiPane() { return isXLargeTablet(this) && !isSimplePreferences(this); } /** Checks if the screen is extra-large (e.g. a 10" tablet is 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 this is forced via {@link #ALWAYS_SIMPLE_PREFS}, or 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 ALWAYS_SIMPLE_PREFS || Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB || !isXLargeTablet(context); } @Override @TargetApi(Build.VERSION_CODES.HONEYCOMB) public void onBuildHeaders(List<Header> target) { if (!isSimplePreferences(this)) { loadHeadersFromResource(R.xml.pref_headers, target); } } /** A listener that updates a preference's summary to match its value. */ private static final Preference.OnPreferenceChangeListener sListener = new Preference.OnPreferenceChangeListener() { @Override public boolean onPreferenceChange(Preference pref, Object value) { pref.setSummary("" + value); return true; } }; /** * Shows a preference's string value on its summary line (below the title * of the preference), and keep the summary updated when the value changes. * * @see #sListener */ private static void showValueAsSummary(Preference pref) { // Set the listener to watch for value changes. pref.setOnPreferenceChangeListener(sListener); // Trigger the listener immediately with the preference's current value. SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(pref.getContext()); sListener.onPreferenceChange(pref, prefs.getAll().get(pref.getKey())); } /** * 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); // Load the preference definitions. addPreferencesFromResource(R.xml.pref_general); // Show the values of preferences in their summary lines. showValueAsSummary(findPreference("openmrs_root_url")); showValueAsSummary(findPreference("openmrs_user")); showValueAsSummary(findPreference("package_server_root_url")); showValueAsSummary(findPreference("apk_update_interval_secs")); } } }