Java tutorial
/* * Copyright 2016 Google Inc. * * 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.android.talkback; import android.app.ActionBar; import android.app.Activity; import android.os.Build; import android.os.Bundle; import android.preference.CheckBoxPreference; import android.preference.Preference; import android.preference.Preference.OnPreferenceChangeListener; import android.preference.PreferenceFragment; import android.preference.PreferenceScreen; import android.support.v4.os.BuildCompat; import android.text.SpannableString; import android.text.style.TtsSpan; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.accessibility.AccessibilityEvent; import com.android.utils.AccessibilityEventUtils; import com.google.android.marvin.talkback.TalkBackService; import java.util.ArrayList; /** * Activity used to set TalkBack's dump events preferences. */ public class TalkBackDumpAccessibilityEventActivity extends Activity { private MenuItem.OnMenuItemClickListener mListener; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setTitle(getString(R.string.title_activity_dump_a11y_event)); ActionBar actionBar = getActionBar(); if (actionBar != null) { actionBar.setDisplayHomeAsUpEnabled(true); } TalkBackDumpAccessibilityEventFragment fragment = new TalkBackDumpAccessibilityEventFragment(); mListener = fragment; getFragmentManager().beginTransaction().replace(android.R.id.content, fragment).commit(); } /** * Finishes the activity when the up button is pressed on the action bar. * Perform function in TalkBackAccessibilityEventFragment when clear_all/check_all button is * pressed. */ @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case android.R.id.home: finish(); return true; case R.id.clear_all: case R.id.check_all: return mListener.onMenuItemClick(item); default: return super.onOptionsItemSelected(item); } } @Override public boolean onCreateOptionsMenu(Menu menu) { MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.dump_a11y_event_menu, menu); return true; } public static class TalkBackDumpAccessibilityEventFragment extends PreferenceFragment implements MenuItem.OnMenuItemClickListener, OnPreferenceChangeListener { private TalkBackService mService; /** * List of all the accessibility event types */ private static final int[] DUMP_A11Y_EVENT_IDS = AccessibilityEventUtils.getAllEventTypes(); /** * List of preference keys */ private ArrayList<String> mDumpEventPrefKeys = new ArrayList<>(DUMP_A11Y_EVENT_IDS.length); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Set preferences to use device-protected storage. if (BuildCompat.isAtLeastN()) { getPreferenceManager().setStorageDeviceProtected(); } mService = TalkBackService.getInstance(); // Compose preference keys from a key prefix and accessibility event types. for (int id : DUMP_A11Y_EVENT_IDS) { mDumpEventPrefKeys.add(getString(R.string.pref_dump_event_key_prefix, id)); } addPreferencesFromResource(R.xml.dump_events_preferences); PreferenceScreen screen = getPreferenceScreen(); for (int i = 0; i < DUMP_A11Y_EVENT_IDS.length; i++) { CheckBoxPreference preference = new CheckBoxPreference(getActivity().getApplicationContext()); preference.setKey(mDumpEventPrefKeys.get(i)); String title = AccessibilityEvent.eventTypeToString(DUMP_A11Y_EVENT_IDS[i]); // Add TtsSpan to the titles to improve readability. SpannableString spannableString = new SpannableString(title); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { TtsSpan ttsSpan = new TtsSpan.TextBuilder(title.replaceAll("_", " ")).build(); spannableString.setSpan(ttsSpan, 0, title.length(), 0 /* no flag */); } preference.setTitle(spannableString); screen.addPreference(preference); preference.setOnPreferenceChangeListener(this); } } private void setAllPreferenceValue(boolean value) { for (String prefKey : mDumpEventPrefKeys) { Preference preference = findPreference(prefKey); if (preference != null) { ((CheckBoxPreference) preference).setChecked(value); onPreferenceChange(preference, value); } } } @Override public boolean onMenuItemClick(MenuItem menuItem) { switch (menuItem.getItemId()) { case R.id.clear_all: setAllPreferenceValue(false); return true; case R.id.check_all: setAllPreferenceValue(true); return true; default: return false; } } @Override public boolean onPreferenceChange(Preference preference, Object newValue) { if (mService != null) { String prefKey = preference.getKey(); int index = mDumpEventPrefKeys.indexOf(prefKey); mService.notifyDumpEventPreferenceChanged(DUMP_A11Y_EVENT_IDS[index], (boolean) newValue); } return true; } } }