Java tutorial
/* * Copyright 2011 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 dev.ronlemire.samplestemplate; import dev.ronlemire.samplestemplate.R; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.content.res.Configuration; import android.graphics.Color; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentTransaction; import android.util.DisplayMetrics; import android.view.Display; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.widget.TextView; public class MainActivity extends ActionBarFragmentActivity { public static final String TAG = "MainActivity"; private FragmentManager fm = getSupportFragmentManager(); private Fragment sampleListFragment; private String sampleSelected; public static View sampleListView; private TextView messageTextView; private SampleListReceiver sampleListReceiver; private IntentFilter sampleListFilter; private MessageFromSampleReceiver messageFromSampleReceiver; private IntentFilter messageFromSampleFilter; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Test whether if enough display space for 2 panes. Only if tablet and // landscape. if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE && isTablet()) { // 2 panes - list on left - sample on right setContentView(R.layout.main_land); StartEmptyFragment(); // clear sample pane } else { // 1 pane - list and sample will overlay each other setContentView(R.layout.main); } // Save reference to List in order to replace later sampleListView = this.findViewById(R.id.list_replacer); messageTextView = (TextView) this.findViewById(R.id.etMessages); messageTextView.setEnabled(false); messageTextView.setTextColor(Color.parseColor("#000000")); // black // Receiver to catch message sent from List after a sample has been // picked sampleListReceiver = new SampleListReceiver(); sampleListFilter = new IntentFilter( SampleListFragment.SAMPLE_LIST_FRAGMENT_BROADCAST_INTENT); // Messages from controls messageFromSampleReceiver = new MessageFromSampleReceiver(); messageFromSampleFilter = new IntentFilter( SampleFragment.MESSAGE_FROM_SAMPLE_INTENT); if (savedInstanceState == null) { StartSampleListFragment(); } else { messageTextView.setText(savedInstanceState.getString("message")); } } @Override protected void onSaveInstanceState(Bundle outState) { outState.putString("message", messageTextView.getText().toString()); super.onSaveInstanceState(outState); } @Override public void onResume() { super.onResume(); registerReceiver(sampleListReceiver, sampleListFilter); registerReceiver(messageFromSampleReceiver, messageFromSampleFilter); } @Override protected void onPause() { super.onPause(); unregisterReceiver(sampleListReceiver); unregisterReceiver(messageFromSampleReceiver); } @Override public void onBackPressed() { ClearMessageBox(); super.onBackPressed(); } // ***************************************************************************** // BroadcastReceivers // ***************************************************************************** class SampleListReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { // Sample selected from list will be in Intent's extra data sampleSelected = intent .getStringExtra(SampleListFragment.SAMPLE_SELECTED); // Start sample fragment depending on which sample was selected ClearMessageBox(); PopFragmentBackStack(); if (sampleSelected.equals("SampleFragment")) { StartSampleFragment(); } } } class MessageFromSampleReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { String message = (String) intent .getSerializableExtra(SampleFragment.OUT_MESSAGE_KEY); messageTextView.setText(message); } } // ***************************************************************************** // Start Fragments // ***************************************************************************** public void StartSampleListFragment() { sampleListFragment = (Fragment) getSupportFragmentManager() .findFragmentById(R.id.list_replacer); sampleListFragment = SampleListFragment .newInstance("inMessageGoesHere"); FragmentTransaction fragmentTransaction = getSupportFragmentManager() .beginTransaction(); fragmentTransaction.replace(R.id.list_replacer, sampleListFragment); fragmentTransaction.commit(); } public void StartEmptyFragment() { Fragment sampleEmptyFragment = (Fragment) fm .findFragmentById(R.id.detail_replacer); sampleEmptyFragment = EmptyFragment.newInstance(); fm.beginTransaction() .replace(R.id.detail_replacer, sampleEmptyFragment).commit(); } public void StartSampleFragment() { if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE && isTablet()) { Fragment sampleFragment = (Fragment) fm .findFragmentById(R.id.detail_replacer); sampleFragment = SampleFragment.newInstance("Sample"); FragmentTransaction transaction = fm.beginTransaction() .replace(R.id.detail_replacer, sampleFragment); transaction.addToBackStack(null); transaction.commit(); } else { SampleFragment sampleFragment = SampleFragment .newInstance("Sample"); FragmentTransaction transaction = getSupportFragmentManager() .beginTransaction() .replace(MainActivity.sampleListView.getId(), sampleFragment); transaction.addToBackStack(null); transaction.commit(); } } // ***************************************************************************** // Action Bar // ***************************************************************************** @Override public boolean onCreateOptionsMenu(Menu menu) { MenuInflater menuInflater = getMenuInflater(); menuInflater.inflate(R.menu.main, menu); // Calling super after populating the menu is necessary here to ensure // that the action bar helpers have a chance to handle this event. return super.onCreateOptionsMenu(menu); } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case android.R.id.home: // Toast.makeText(this, "Tapped home", Toast.LENGTH_SHORT).show(); ReturnToSampleList(); break; case R.id.menu_refresh: // Toast.makeText(this, "Fake refreshing...", // Toast.LENGTH_SHORT).show(); ReturnToSampleList(); break; } return super.onOptionsItemSelected(item); } // ***************************************************************************** // Helper methods // ***************************************************************************** private boolean isTablet() { Display display = getWindowManager().getDefaultDisplay(); DisplayMetrics displayMetrics = new DisplayMetrics(); display.getMetrics(displayMetrics); int width = displayMetrics.widthPixels / displayMetrics.densityDpi; int height = displayMetrics.heightPixels / displayMetrics.densityDpi; double screenDiagonal = Math.sqrt(width * width + height * height); return (screenDiagonal >= 8.5); } private void ReturnToSampleList() { ClearMessageBox(); PopFragmentBackStack(); if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE && isTablet()) { StartSampleListFragment(); StartEmptyFragment(); } else { SampleListFragment sampleListFragment = SampleListFragment .newInstance("List"); getSupportFragmentManager() .beginTransaction() .replace(MainActivity.sampleListView.getId(), sampleListFragment).commit(); } } private void PopFragmentBackStack() { // http://stackoverflow.com/questions/5802141/is-this-the-right-way-to-clean-up-fragment-back-stack-when-leaving-a-deeply-nest fm.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE); } private void ClearMessageBox() { messageTextView.setText(""); } }