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--- android_learning:headfirst_android_development_notes:chapter_10 [2016/03/16 03:45] – [Foreword] mithat
+++ android_learning:headfirst_android_development_notes:chapter_10 [2016/03/16 04:49] (current) – [Foreword] mithat
@@ Line 1: / Line 1: @@
 ====== Chapter 10 ======
-<WRAP center round info 60%>
-Under development.
-</WRAP>
 ===== Foreword =====
-I think Android's action bars, action items, and navigation drawers are implemented pretty terribly---the last of these being especially painful to write code for. It's as though thousands of years of desktop app development framework development never happened.
+I think Android's action bars, action items, and navigation drawers are implemented pretty terribly---the last of these being especially painful to write code for. The backstack for Fragments isn't much better. It's as though thousands of years of desktop app development framework development never happened.
-If you get frustrated in this chapter, I feel your pain. It's not you, it's Android. If there's good news, it's that Android Studio's "Blank" activity template sets up some of necessary scaffolding and boilerplate code for you. But you still need to know the inner workings.
+If you get frustrated in this chapter, I feel your pain. It's not you, it's Android. If there's good news, it's that Android Studio's "Blank" activity template sets up some of necessary scaffolding and boilerplate code for you. But you still need to know the inner workings. So ...
 ===== p. 398: Creating the app =====
@@ Line 71: / Line 67: @@
 </file>
-Notice the required empty public constructor not included in the book's code.
+Notice the required empty public constructor not included in the book's code. The [[http://developer.android.com/reference/android/app/Fragment.html|official docs]] assert that:
-<WRAP center round info 90%>
+> All subclasses of Fragment must include a public no-argument constructor.
-The [[http://developer.android.com/reference/android/app/Fragment.html|official docs say]] "All subclasses of Fragment must include a public no-argument constructor." The book doesn't follow this practice, but you should.
-</WRAP>
+The book doesn't follow this practice, but you should.
 And here's the layout:
@@ Line 228: / Line 223: @@
 ===== p. 417: Anonymous classes =====
-In case you're not familiar with the construct of the ''ActionBarDrawerToggle'' definition code, it's using Java's anonymous inner class syntax. Anonymous inner classes are typically used as shortcuts to creating a derived class that you'll only use once.
+In case you're not familiar with how the ''ActionBarDrawerToggle'' here is being defined, it's using Java's anonymous inner class syntax. Anonymous inner classes are typically used as shortcuts to creating a derived class that you'll only use once.
 ===== p. 422: Code block =====
@@ Line 416: / Line 411: @@
 </file>
+===== pp. 429-434 =====
+I think the length of the ActivityMain class definition is an indication of how poorly designed the Android features introduced in this and the previous chapter are. But you be the judge.
+Note when you add code that references the FragmentManager class to your code, you'll be offered two different class options to import. Use ''android.app.FragmentManager''.
+<file java ActivityMain.java>
+package com.hfad.bitsandpizzas;
+import android.app.Activity;
+import android.app.Fragment;
+import android.app.FragmentManager;
+import android.app.FragmentTransaction;
+import android.content.Intent;
+import android.content.res.Configuration;
+import android.os.Bundle;
+import android.support.v4.widget.DrawerLayout;
+import android.support.v7.app.ActionBarDrawerToggle;
+import android.view.Menu;
+import android.view.MenuItem;
+import android.view.View;
+import android.widget.AdapterView;
+import android.widget.ArrayAdapter;
+import android.widget.ListView;
+import android.widget.ShareActionProvider;
+import android.widget.Toast;
+public class MainActivity extends Activity {
+    private ShareActionProvider shareActionProvider;
+    private String[] titles;        // local list of categories
+    private ListView drawerList;
+    private DrawerLayout drawerLayout;
+    private ActionBarDrawerToggle drawerToggle;
+    private int currentPosition = 0;
+    private class DrawerItemClickListener implements ListView.OnItemClickListener {
+        @Override
+        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
+            selectItem(position);
+        }
+    }
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+        // populate local list of categories
+        titles = getResources().getStringArray(R.array.titles);
+        drawerList = (ListView) findViewById(R.id.drawer);
+        drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
+        // Populate the list view
+        drawerList.setAdapter(new ArrayAdapter<String>(this,
+                android.R.layout.simple_list_item_activated_1, titles));
+        drawerList.setOnItemClickListener(new DrawerItemClickListener());
+        // Display the correct fragment
+        if (savedInstanceState != null) {
+            currentPosition = savedInstanceState.getInt("position");
+            setActionBarTitle(currentPosition);
+        } else {  // if MainActivity newly created ...
+            selectItem(0);
+        }
+        // Create the ActionBarToggle ...
+        drawerToggle = new ActionBarDrawerToggle(this, drawerLayout,
+                R.string.open_drawer, R.string.close_drawer) {
+            @Override
+            public void onDrawerClosed(View drawerView) {
+                super.onDrawerClosed(drawerView);
+                invalidateOptionsMenu();
+            }
+            @Override
+            public void onDrawerOpened(View drawerView) {
+                super.onDrawerOpened(drawerView);
+                invalidateOptionsMenu();
+            }
+        };
+        // ... and set the ActionBarToggle as the drawer's listener
+        drawerLayout.setDrawerListener(drawerToggle);
+        getActionBar().setDisplayHomeAsUpEnabled(true);
+        getActionBar().setHomeButtonEnabled(true);
+        // Add a listener for changes in the backstack to the fragment manager,
+        // use that to set titles appropriately and check drawer items.
+        getFragmentManager().addOnBackStackChangedListener(
+                new FragmentManager.OnBackStackChangedListener() {
+                    @Override
+                    public void onBackStackChanged() {
+                        FragmentManager fragMan = getFragmentManager();
+                        Fragment fragment = fragMan.findFragmentByTag("visible_fragment");
+                        if (fragment instanceof TopFragment) {
+                            currentPosition = 0;
+                        }
+                        if (fragment instanceof PizzaFragment) {
+                            currentPosition = 1;
+                        }
+                        if (fragment instanceof PastaFragment) {
+                            currentPosition = 2;
+                        }
+                        if (fragment instanceof StoresFragment) {
+                            currentPosition = 3;
+                        }
+                        setActionBarTitle(currentPosition);
+                        drawerList.setItemChecked(currentPosition, true);
+                    }
+                }
+        );
+    }
+    @Override
+    protected void onSaveInstanceState(Bundle outState) {
+        super.onSaveInstanceState(outState);
+        outState.putInt("position", currentPosition);
+    }
+    @Override
+    protected void onPostCreate(Bundle savedInstanceState) {
+        super.onPostCreate(savedInstanceState);
+        // sync toggle state (after onRestoreInstanceState has occurred).
+        drawerToggle.syncState();
+    }
+    @Override
+    public void onConfigurationChanged(Configuration newConfig) {
+        super.onConfigurationChanged(newConfig);
+        drawerToggle.onConfigurationChanged(newConfig);
+    }
+    @Override
+    public boolean onPrepareOptionsMenu(Menu menu) {
+        // If the drawer is open, hide action items related to the content view.
+        boolean drawerOpen = drawerLayout.isDrawerOpen(drawerList);
+        menu.findItem(R.id.action_share).setVisible(!drawerOpen);
+        return super.onPrepareOptionsMenu(menu);
+    }
+    private void selectItem(int position) {
+        currentPosition = position;
+        // update the main content by replacing fragments
+        Fragment fragment;
+        switch (position) {
+            case 1:
+                fragment = new PizzaFragment();
+                break;
+            case 2:
+                fragment = new PastaFragment();
+                break;
+            case 3:
+                fragment = new StoresFragment();
+                break;
+            default:
+                fragment = new TopFragment();
+        }
+        FragmentTransaction ft = getFragmentManager().beginTransaction();
+        ft.replace(R.id.content_frame, fragment, "visible_fragment")
+                .addToBackStack(null)
+                .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
+                .commit();
+        //Set the action bar title
+        setActionBarTitle(position);
+        //Close drawer
+        drawerLayout.closeDrawer(drawerList);
+    }
+    private void setActionBarTitle(int position) {
+        String title;
+        if (position == 0) {
+            title = getResources().getString(R.string.app_name);
+        } else {
+            title = titles[position];
+        }
+        getActionBar().setTitle(title);
+    }
+    @Override
+    public boolean onCreateOptionsMenu(Menu menu) {
+        // Add menu_main items to the action bar (if present):
+        getMenuInflater().inflate(R.menu.menu_main, menu);
+        MenuItem menuItem = menu.findItem(R.id.action_share);
+        shareActionProvider = (ShareActionProvider) menuItem.getActionProvider();
+        setIntent("This is example text.");
+        return super.onCreateOptionsMenu(menu);
+    }
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        // If a drawer option has been clicked ...
+        if (drawerToggle.onOptionsItemSelected(item)) {
+            // do nothing and return.
+            return true;
+        }
+        // ... otherwise ...
+        switch (item.getItemId()) {
+            case R.id.action_create_order:
+                //Code to run when the Create Order item is clicked
+                Intent intent = new Intent(this, OrderActivity.class);
+                startActivity(intent);
+                return true;
+            case R.id.action_settings:
+                //Code to run when the settings item is clicked
+                Toast.makeText(MainActivity.this, "Settings!", Toast.LENGTH_SHORT).show();
+                return true;
+            default:
+                return super.onOptionsItemSelected(item);
+        }
+    }
+    private void setIntent(String text) {
+        Intent intent = new Intent(Intent.ACTION_SEND);
+        intent.setType("text/plain");
+        intent.putExtra(Intent.EXTRA_TEXT, text);
+        shareActionProvider.setShareIntent(intent);
+    }
+}
+</file>