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 tk.wasdennnoch.androidn_ify.ui.emergency; import android.app.Activity; import android.app.Fragment; import android.app.FragmentManager; import android.content.res.Configuration; import android.support.annotation.LayoutRes; import android.support.design.widget.TabLayout; import android.support.design.widget.TabLayout.TabLayoutOnPageChangeListener; import android.support.v13.app.FragmentStatePagerAdapter; import android.support.v4.view.ViewPager; import android.util.Pair; import android.view.MenuItem; import android.widget.Toolbar; import com.android.internal.annotations.VisibleForTesting; import java.util.ArrayList; import tk.wasdennnoch.androidn_ify.R; /** * An activity uses a tab layout to separate personal and medical information * from emergency contacts. */ @SuppressWarnings({ "deprecation", "SameParameterValue", "WeakerAccess", "ConstantConditions" }) public abstract class EmergencyTabActivity extends Activity { private ViewPagerAdapter mTabsAdapter; private TabLayout mTabLayout; private ArrayList<Pair<String, Fragment>> mFragments; @Override protected void onResume() { super.onResume(); int display_mode = getResources().getConfiguration().orientation; if (display_mode == Configuration.ORIENTATION_PORTRAIT) { mTabLayout.setTabMode(TabLayout.MODE_FIXED); mTabLayout.setTabGravity(TabLayout.GRAVITY_FILL); } } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { // Respond to the action bar's Up/Home button. case android.R.id.home: onBackPressed(); return true; } return super.onOptionsItemSelected(item); } /** Returns the index of the currently selected tab. */ @VisibleForTesting public int getSelectedTabPosition() { return mTabLayout.getSelectedTabPosition(); } @Override public void setContentView(@LayoutRes int layoutResID) { super.setContentView(layoutResID); setupTabs(); Toolbar toolbar = (Toolbar) findViewById(R.id.action_bar); setActionBar(toolbar); getActionBar().setDisplayHomeAsUpEnabled(true); } /** Selects the tab at index {@code selectedTabIndex}. */ public void selectTab(int selectedTabIndex) { if (mTabLayout != null && selectedTabIndex >= 0 && selectedTabIndex < mTabLayout.getTabCount()) { mTabLayout.getTabAt(selectedTabIndex).select(); } } protected 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); } } public TabLayout getTabLayout() { return mTabLayout; } /** Return the fragments. */ public ArrayList<Pair<String, Fragment>> getFragments() { return mFragments; } /** Return number of fragments to show in the tabs. */ public int getNumberFragments() { return mFragments.size(); } /** Returns the fragments to show in the tabs. */ protected abstract ArrayList<Pair<String, Fragment>> setUpFragments(); /** The adapter used to handle the two fragments. */ private 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; } } }