Use only one layout, with a dynamically sized PagerAdapter

it is more straightforward to only have one viewpager that can be
flipped through. This makes it easier to restore the user's default way
of connecting (bluetooth via wifi) and also simplifies the setup and
the what-tab-am-I-on checks.

* Remeber what tab (wifi/bluetooth) the user last used and restore that
  on next launch
* respect Android's guidelines and ask the user whether Bluetooth should
  be enabled when the user switches to the BT tab and BT is disabled.
  → if the user declines, select wifi tab instead

Fix a lifecycle problem (bt connection would be cut if bt was not
enabled before launching the remote, only restore disbled state if
really finishing, not on configuration change like rotating the screen)

Change-Id: Ice3a5c877a2a4810a80a0f76edea713700fe9c8c
Reviewed-on: https://gerrit.libreoffice.org/7090
Reviewed-by: Andrzej Hunt <andrzej.hunt@collabora.com>
Tested-by: Andrzej Hunt <andrzej.hunt@collabora.com>

2 files changed, 69 insertions, 124 deletions

diff --git a/android/sdremote/src/org/libreoffice/impressremote/activity/ComputersActivity.java b/android/sdremote/src/org/libreoffice/impressremote/activity/ComputersActivity.java
index 0c7bd685640b..9329cd950110 100644
--- a/android/sdremote/src/org/libreoffice/impressremote/activity/ComputersActivity.java
+++ b/android/sdremote/src/org/libreoffice/impressremote/activity/ComputersActivity.java
@@ -8,36 +8,40 @@
  */
 package org.libreoffice.impressremote.activity;
 
+import android.bluetooth.BluetoothAdapter;
+import android.content.Context;
 import android.content.Intent;
+import android.content.SharedPreferences;
 import android.os.Bundle;
-import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentTransaction;
-import android.support.v4.view.PagerAdapter;
 import android.support.v4.view.ViewPager;
 import android.support.v7.app.ActionBar;
+import android.support.v7.app.ActionBar.Tab;
 import android.support.v7.app.ActionBarActivity;
 import android.view.Menu;
 import android.view.MenuItem;
 
 import org.libreoffice.impressremote.adapter.ComputersPagerAdapter;
-import org.libreoffice.impressremote.fragment.ComputersFragment;
-import org.libreoffice.impressremote.util.BluetoothOperator;
-import org.libreoffice.impressremote.util.Fragments;
+import org.libreoffice.impressremote.fragment.ComputersFragment.Type;
 import org.libreoffice.impressremote.util.Intents;
 import org.libreoffice.impressremote.R;
-import org.libreoffice.impressremote.util.Preferences;
-import org.libreoffice.impressremote.util.SavedStates;
 
 public class ComputersActivity extends ActionBarActivity implements ActionBar.TabListener, ViewPager.OnPageChangeListener {
-    private boolean mBluetoothWasEnabled;
+    private static final int REQUEST_ENABLE_BT = 0;
+    private static final String SELECT_BLUETOOTH = "SELECT_BLUETOOTH";
+    private static final BluetoothAdapter btAdapter = BluetoothAdapter.getDefaultAdapter();
+    private static boolean disableBTOnQuit = btAdapter != null && !btAdapter.isEnabled();
+    private static Tab btTab;
+    private static Tab wifiTab;
+    private boolean isInitializing;
+    private ComputersPagerAdapter computersPagerAdapter = new ComputersPagerAdapter(getSupportFragmentManager());
 
     @Override
     protected void onCreate(Bundle aSavedInstanceState) {
         super.onCreate(aSavedInstanceState);
+        isInitializing = true;
 
-        saveBluetoothState(aSavedInstanceState);
-        BluetoothOperator.enable();
-
+        setContentView(R.layout.activity_computers);
         // Looks hacky but it seems to be the best way to set activity’s title
         // different to application’s label. The other way is setting title
         // to intents filter but it shows wrong label for recent apps screen then.
@@ -47,72 +51,48 @@ public class ComputersActivity extends ActionBarActivity implements ActionBar.Ta
         aActionBar.setTitle(R.string.title_computers);
         aActionBar.setDisplayShowTitleEnabled(true);
 
-        if (BluetoothOperator.isAvailable()) {
-            setUpComputersLists();
-        }
-        else {
-            Fragment aComputersFragment = ComputersFragment.newInstance(ComputersFragment.Type.WIFI);
-            Fragments.Operator.add(this, aComputersFragment);
-        }
-    }
-
-    private void saveBluetoothState(Bundle aSavedInstanceState) {
-        // In more ideal world this work should be done at the service.
-        // Unfortunately service cannot save or restore its state.
-        // On other hand we should remember Bluetooth state exactly
-        // after the app’s start and pass it during recreation cycle.
-
-        if (!BluetoothOperator.isAvailable()) {
-            return;
-        }
-
-        mBluetoothWasEnabled = wasBluetoothEnabled(aSavedInstanceState);
-    }
+        btTab = aActionBar.newTab().setTabListener(this)
+                .setText(R.string.title_bluetooth);
+        wifiTab = aActionBar.newTab().setTabListener(this)
+                .setText(R.string.title_wifi);
 
-    private boolean wasBluetoothEnabled(Bundle aSavedInstanceState) {
-        if (aSavedInstanceState == null) {
-            return BluetoothOperator.getAdapter().isEnabled();
+        if (btAdapter != null) {
+            computersPagerAdapter.addFragment(Type.BLUETOOTH);
+            aActionBar.addTab(btTab);
         }
 
-        return aSavedInstanceState.getBoolean(SavedStates.Keys.BLUETOOTH_ENABLED);
-    }
-
-    private void setUpComputersLists() {
-        setContentView(R.layout.activity_computers);
-
-        ActionBar aActionBar = getSupportActionBar();
+        computersPagerAdapter.addFragment(Type.WIFI);
 
-        aActionBar.addTab(buildActionBarTab(
-            R.string.title_bluetooth), ComputersPagerAdapter.PagesIndices.BLUETOOTH);
-        aActionBar.addTab(buildActionBarTab(
-            R.string.title_wifi), ComputersPagerAdapter.PagesIndices.WIFI);
-
-        ViewPager aComputersPager = getComputersPager();
-
-        aComputersPager.setAdapter(new ComputersPagerAdapter(getSupportFragmentManager()));
+        ViewPager aComputersPager = (ViewPager) findViewById(R.id.pager_computers);
+        aComputersPager.setAdapter(computersPagerAdapter);
         aComputersPager.setOnPageChangeListener(this);
 
-        getSupportActionBar().setSelectedNavigationItem(loadTabIndex());
+        // select wifitab - onStart() decides whether BT-Tab should be selected
+        // when the user starts the remote (and thus trigger the BT-enable
+        // intent in case BT was disabled)
+        isInitializing = false;
+        aActionBar.addTab(wifiTab, true);
     }
 
-    private ActionBar.Tab buildActionBarTab(int aTitleResourceId) {
-        ActionBar.Tab aTab = getSupportActionBar().newTab();
-
-        aTab.setTabListener(this);
-        aTab.setText(aTitleResourceId);
-
-        return aTab;
+    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
+        if (requestCode == REQUEST_ENABLE_BT) {
+            if (resultCode != RESULT_OK) {
+                getSupportActionBar().selectTab(wifiTab);
+            }
+        }
     }
 
     @Override
-    public void onTabSelected(ActionBar.Tab aTab, FragmentTransaction aTransaction) {
-        getComputersPager().setCurrentItem(aTab.getPosition());
-
+    public void onTabSelected(Tab aTab, FragmentTransaction aTransaction) {
+        ((ViewPager) findViewById(R.id.pager_computers)).setCurrentItem(aTab
+                .getPosition());
         supportInvalidateOptionsMenu();
-    }
-
-    private ViewPager getComputersPager() {
-        return (ViewPager) findViewById(R.id.pager_computers);
+        if (isInitializing) { return; }
+        if (aTab.equals(btTab) && !btAdapter.isEnabled()) {
+            Intent enableBtIntent = new Intent(
+                    BluetoothAdapter.ACTION_REQUEST_ENABLE);
+            startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
+        }
     }
 
     @Override
@@ -136,12 +116,6 @@ public class ComputersActivity extends ActionBarActivity implements ActionBar.Ta
     public void onPageScrollStateChanged(int aPosition) {
     }
 
-    private int loadTabIndex() {
-        Preferences aPreferences = Preferences.getApplicationStatesInstance(this);
-
-        return aPreferences.getInt(Preferences.Keys.SELECTED_COMPUTERS_TAB_INDEX);
-    }
-
     @Override
     public boolean onCreateOptionsMenu(Menu aMenu) {
         getMenuInflater().inflate(R.menu.menu_action_bar_computers, aMenu);
@@ -151,23 +125,8 @@ public class ComputersActivity extends ActionBarActivity implements ActionBar.Ta
 
     @Override
     public boolean onPrepareOptionsMenu(Menu aMenu) {
-        if (!BluetoothOperator.isAvailable()) {
-            return super.onPrepareOptionsMenu(aMenu);
-        }
-
-        MenuItem aComputerAddingMenuItem = aMenu.findItem(R.id.menu_add_computer);
-
-        switch (getSupportActionBar().getSelectedNavigationIndex()) {
-            case ComputersPagerAdapter.PagesIndices.BLUETOOTH:
-                aComputerAddingMenuItem.setVisible(false);
-                break;
-
-            case ComputersPagerAdapter.PagesIndices.WIFI:
-                aComputerAddingMenuItem.setVisible(true);
-
-            default:
-                break;
-        }
+        aMenu.findItem(R.id.menu_add_computer)
+            .setVisible(getSupportActionBar().getSelectedTab().equals(wifiTab));
 
         return super.onPrepareOptionsMenu(aMenu);
     }
@@ -211,32 +170,29 @@ public class ComputersActivity extends ActionBarActivity implements ActionBar.Ta
     protected void onStop() {
         super.onStop();
 
-        Preferences aPreferences = Preferences.getApplicationStatesInstance(this);
-        int aTabIndex = getSupportActionBar().getSelectedNavigationIndex();
-
-        aPreferences.setInt(Preferences.Keys.SELECTED_COMPUTERS_TAB_INDEX, aTabIndex);
+        SharedPreferences sharedPref = getPreferences(Context.MODE_PRIVATE);
+        SharedPreferences.Editor editor = sharedPref.edit();
+        editor.putBoolean(SELECT_BLUETOOTH, getSupportActionBar()
+                .getSelectedTab().equals(btTab));
+        editor.commit();
     }
 
     @Override
-    protected void onSaveInstanceState(Bundle aSavedInstanceState) {
-        super.onSaveInstanceState(aSavedInstanceState);
+    protected void onStart() {
+        super.onStart();
 
-        aSavedInstanceState.putBoolean(SavedStates.Keys.BLUETOOTH_ENABLED, mBluetoothWasEnabled);
+        SharedPreferences sharedPref = getPreferences(Context.MODE_PRIVATE);
+        if (sharedPref.getBoolean(SELECT_BLUETOOTH, btAdapter != null)) {
+            getSupportActionBar().selectTab(btTab);
+        }
     }
 
     @Override
     protected void onDestroy() {
         super.onDestroy();
-
-        if (!BluetoothOperator.isAvailable()) {
-            return;
+        if (isFinishing() && disableBTOnQuit) {
+            btAdapter.disable();
         }
-
-        if (mBluetoothWasEnabled) {
-            return;
-        }
-
-        BluetoothOperator.disable();
     }
 }
 
diff --git a/android/sdremote/src/org/libreoffice/impressremote/adapter/ComputersPagerAdapter.java b/android/sdremote/src/org/libreoffice/impressremote/adapter/ComputersPagerAdapter.java
index f06a7f1ddeda..0a09fd2f0736 100644
--- a/android/sdremote/src/org/libreoffice/impressremote/adapter/ComputersPagerAdapter.java
+++ b/android/sdremote/src/org/libreoffice/impressremote/adapter/ComputersPagerAdapter.java
@@ -15,37 +15,26 @@ import android.support.v4.app.FragmentPagerAdapter;
 import org.libreoffice.impressremote.fragment.ComputersFragment;
 
 public class ComputersPagerAdapter extends FragmentPagerAdapter {
-    private static final int PAGER_SIZE = 2;
-
-    public static final class PagesIndices {
-        private PagesIndices() {
-        }
-
-        public static final int BLUETOOTH = 0;
-        public static final int WIFI = 1;
-    }
+    private int pager_size = 0;
+    private ComputersFragment.Type tabs[] = new ComputersFragment.Type[2];
 
     public ComputersPagerAdapter(FragmentManager aFragmentManager) {
         super(aFragmentManager);
     }
 
+    public void addFragment(ComputersFragment.Type type) {
+        tabs[pager_size] = type;
+        pager_size++;
+    }
+
     @Override
     public Fragment getItem(int aPosition) {
-        switch (aPosition) {
-            case PagesIndices.BLUETOOTH:
-                return ComputersFragment.newInstance(ComputersFragment.Type.BLUETOOTH);
-
-            case PagesIndices.WIFI:
-                return ComputersFragment.newInstance(ComputersFragment.Type.WIFI);
-
-            default:
-                return null;
-        }
+        return ComputersFragment.newInstance(tabs[aPosition]);
     }
 
     @Override
     public int getCount() {
-        return PAGER_SIZE;
+        return pager_size;
     }
 }