Java tutorial
/* * Copyright (C) 2017 Angel Garcia * * 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 com.xengar.android.englishverbs.ui; import android.annotation.TargetApi; import android.content.Context; import android.content.Intent; import android.content.SharedPreferences; import android.content.res.Configuration; import android.media.Ringtone; import android.media.RingtoneManager; import android.net.Uri; import android.os.Build; import android.os.Bundle; import android.preference.CheckBoxPreference; import android.preference.EditTextPreference; import android.preference.ListPreference; import android.preference.Preference; import android.preference.PreferenceActivity; import android.preference.PreferenceFragment; import android.preference.PreferenceManager; import android.preference.RingtonePreference; import android.preference.SwitchPreference; import android.support.v4.app.NavUtils; import android.support.v7.app.ActionBar; import android.text.TextUtils; import android.view.MenuItem; import com.xengar.android.englishverbs.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 AppCompatPreferenceActivity implements SharedPreferences.OnSharedPreferenceChangeListener { /** * 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 if (preference instanceof RingtonePreference) { // For ringtone preferences, look up the correct display value // using RingtoneManager. if (TextUtils.isEmpty(stringValue)) { // Empty values correspond to 'silent' (no ringtone). //preference.setSummary(R.string.pref_ringtone_silent); } else { Ringtone ringtone = RingtoneManager.getRingtone(preference.getContext(), Uri.parse(stringValue)); if (ringtone == null) { // Clear the summary if there was a lookup error. preference.setSummary(null); } else { // Set the summary to reflect the new ringtone display // name. String name = ringtone.getTitle(preference.getContext()); preference.setSummary(name); } } } else if (preference instanceof SwitchPreference) { // For a boolean value, set the default value "true" preference.setDefaultValue((stringValue.contains("t"))); } else { // For all other preferences, set the summary to the value's // simple string representation. 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; } /** * 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' current value. if (preference instanceof ListPreference || preference instanceof EditTextPreference) { sBindPreferenceSummaryToValueListener.onPreferenceChange(preference, PreferenceManager .getDefaultSharedPreferences(preference.getContext()).getString(preference.getKey(), "")); } else if (preference instanceof SwitchPreference || preference instanceof CheckBoxPreference) { sBindPreferenceSummaryToValueListener.onPreferenceChange(preference, PreferenceManager .getDefaultSharedPreferences(preference.getContext()).getBoolean(preference.getKey(), true)); } } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setupActionBar(); getSupportActionBar().setDisplayHomeAsUpEnabled(true); } /** * Set up the {@link android.app.ActionBar}, if the API is available. */ private void setupActionBar() { ActionBar actionBar = getSupportActionBar(); if (actionBar != null) { // Show the Up button in the action bar. actionBar.setDisplayHomeAsUpEnabled(true); } } @Override public boolean onMenuItemSelected(int featureId, MenuItem item) { int id = item.getItemId(); if (id == android.R.id.home) { if (!super.onMenuItemSelected(featureId, item)) { NavUtils.navigateUpFromSameTask(this); } return true; } return super.onMenuItemSelected(featureId, item); } /** * {@inheritDoc} */ @Override public boolean onIsMultiPane() { return isXLargeTablet(this); } /** * {@inheritDoc} */ @Override @TargetApi(Build.VERSION_CODES.HONEYCOMB) public void onBuildHeaders(List<Header> target) { loadHeadersFromResource(R.xml.pref_headers, target); } /** * This method stops fragment injection in malicious applications. * Make sure to deny any unknown fragments here. */ protected boolean isValidFragment(String fragmentName) { return PreferenceFragment.class.getName().equals(fragmentName) || GeneralPreferenceFragment.class.getName().equals(fragmentName); } @Override public void onStart() { super.onStart(); } @Override public void onStop() { super.onStop(); } // Registers a shared preference change listener that gets notified when preferences change. @Override protected void onResume() { SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this); sp.registerOnSharedPreferenceChangeListener(this); super.onResume(); } // Unregisters a shared preference change listener. @Override protected void onPause() { SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this); sp.unregisterOnSharedPreferenceChangeListener(this); super.onPause(); } /** * Called after a preference changes. * @param sharedPreferences SharedPreferences * @param key key */ @Override public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) { /*if ( key.equals(getString(pref_key_percentage_units)) ) { // percentage units have changed. Update the units preference accordingly PrefUtils.toggleDisplayMode(this); }*/ } /** * 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); setHasOptionsMenu(true); // 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("example_text")); //bindPreferenceSummaryToValue(findPreference("example_list")); bindPreferenceSummaryToValue(findPreference(getString(R.string.pref_translation_language))); bindPreferenceSummaryToValue(findPreference(getString(R.string.pref_favorite_mode_list))); } @Override public boolean onOptionsItemSelected(MenuItem item) { int id = item.getItemId(); if (id == android.R.id.home) { startActivity(new Intent(getActivity(), MainActivity.class)); return true; } return super.onOptionsItemSelected(item); } } }