Java tutorial
/* * Copyright (C) 2016 The Android Open Source Project * * 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.emergency.view; import android.app.Activity; import android.app.Fragment; import android.app.FragmentManager; import android.content.Intent; import android.content.SharedPreferences; import android.os.Bundle; import android.support.annotation.LayoutRes; import android.support.design.widget.TabLayout; import android.support.design.widget.TabLayout.TabLayoutOnPageChangeListener; import android.support.design.widget.TabLayout.ViewPagerOnTabSelectedListener; import android.support.v13.app.FragmentStatePagerAdapter; import android.support.v4.view.ViewPager; import android.support.v7.preference.PreferenceManager; import android.text.TextUtils; import android.util.Pair; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.view.WindowManager; import android.widget.LinearLayout; import android.widget.TextView; import android.widget.Toolbar; import android.widget.ViewFlipper; import com.android.emergency.PreferenceKeys; import com.android.emergency.R; import com.android.emergency.edit.EditInfoActivity; import com.android.emergency.util.PreferenceUtils; import com.android.internal.annotations.VisibleForTesting; import com.android.internal.logging.MetricsLogger; import com.android.internal.logging.nano.MetricsProto.MetricsEvent; import java.util.ArrayList; /** * Activity for viewing emergency information. */ public class ViewInfoActivity extends Activity { private TextView mPersonalCardLargeItem; private SharedPreferences mSharedPreferences; private LinearLayout mPersonalCard; private ViewFlipper mViewFlipper; private ViewPagerAdapter mTabsAdapter; private TabLayout mTabLayout; private ArrayList<Pair<String, Fragment>> mFragments; private Menu mMenu; @Override public void setContentView(@LayoutRes int layoutResID) { super.setContentView(layoutResID); setupTabs(); Toolbar toolbar = (Toolbar) findViewById(R.id.action_bar); setActionBar(toolbar); getActionBar().setDisplayHomeAsUpEnabled(true); } @Override protected void onCreate(Bundle savedInstanceState) { getWindow().addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED); super.onCreate(savedInstanceState); setContentView(R.layout.view_activity_layout); mSharedPreferences = PreferenceManager.getDefaultSharedPreferences(this); mPersonalCard = (LinearLayout) findViewById(R.id.name_and_dob_linear_layout); mPersonalCardLargeItem = (TextView) findViewById(R.id.personal_card_large); mViewFlipper = (ViewFlipper) findViewById(R.id.view_flipper); MetricsLogger.visible(this, MetricsEvent.ACTION_VIEW_EMERGENCY_INFO); } @Override public void onResume() { super.onResume(); loadName(); // Update the tabs: new info might have been added/deleted from the edit screen that // could lead to adding/removing a fragment setupTabs(); maybeHideTabs(); } private void loadName() { String name = mSharedPreferences.getString(PreferenceKeys.KEY_NAME, ""); if (TextUtils.isEmpty(name)) { mPersonalCard.setVisibility(View.GONE); } else { mPersonalCard.setVisibility(View.VISIBLE); mPersonalCardLargeItem.setText(name); } } private void maybeHideTabs() { // Show a TextView with "No information provided" if there are no fragments. if (mFragments.size() == 0) { mViewFlipper.setDisplayedChild(mViewFlipper.indexOfChild(findViewById(R.id.no_info))); } else { mViewFlipper.setDisplayedChild(mViewFlipper.indexOfChild(findViewById(R.id.tabs))); } TabLayout tabLayout = mTabLayout; if (mFragments.size() <= 1) { tabLayout.setVisibility(View.GONE); } else { tabLayout.setVisibility(View.VISIBLE); } } @Override public boolean onCreateOptionsMenu(Menu menu) { MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.view_info_menu, menu); mMenu = menu; return super.onCreateOptionsMenu(menu); } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case android.R.id.home: onBackPressed(); return true; case R.id.action_edit: Intent intent = new Intent(this, EditInfoActivity.class); intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); startActivity(intent); return true; } return super.onOptionsItemSelected(item); } /** Return the tab layout. */ @VisibleForTesting public TabLayout getTabLayout() { return mTabLayout; } @VisibleForTesting public Menu getMenu() { return mMenu; } /** Return the fragments. */ @VisibleForTesting public ArrayList<Pair<String, Fragment>> getFragments() { return mFragments; } private ArrayList<Pair<String, Fragment>> setUpFragments() { // Return only the fragments that have at least one piece of information set: ArrayList<Pair<String, Fragment>> fragments = new ArrayList<>(2); if (PreferenceUtils.hasAtLeastOnePreferenceSet(this)) { fragments.add(Pair.create(getResources().getString(R.string.tab_title_info), ViewEmergencyInfoFragment.newInstance())); } if (PreferenceUtils.hasAtLeastOneEmergencyContact(this)) { fragments.add(Pair.create(getResources().getString(R.string.tab_title_contacts), ViewEmergencyContactsFragment.newInstance())); } return fragments; } private void setupTabs() { mFragments = setUpFragments(); mTabLayout = (TabLayout) findViewById(R.id.sliding_tabs); if (mTabsAdapter == null) { // The viewpager that will host the section contents. ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager); mTabsAdapter = new ViewPagerAdapter(getFragmentManager()); viewPager.setAdapter(mTabsAdapter); mTabLayout.setTabsFromPagerAdapter(mTabsAdapter); // Set a listener via setOnTabSelectedListener(OnTabSelectedListener) to be notified // when any tab's selection state has been changed. mTabLayout.setOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(viewPager)); // Use a TabLayout.TabLayoutOnPageChangeListener to forward the scroll and selection // changes to this layout viewPager.addOnPageChangeListener(new TabLayoutOnPageChangeListener(mTabLayout)); } else { mTabsAdapter.notifyDataSetChanged(); mTabLayout.setTabsFromPagerAdapter(mTabsAdapter); } } /** The adapter used to handle the two fragments. */ protected class ViewPagerAdapter extends FragmentStatePagerAdapter { public ViewPagerAdapter(FragmentManager fm) { super(fm); } @Override public Fragment getItem(int position) { return mFragments.get(position).second; } @Override public int getCount() { return mFragments.size(); } @Override public CharSequence getPageTitle(int position) { return mFragments.get(position).first; } @Override public int getItemPosition(Object object) { // The default implementation assumes that items will never change position and always // returns POSITION_UNCHANGED. This is how you can specify that the positions can change return FragmentStatePagerAdapter.POSITION_NONE; } } }