Root access with ES File Explorer

Open ES File Explore, go to settings  scroll down to Home Directory and change it to "/".

Now you have access to the entire file system.

You can read more here

Add/Remove Fragment - Simple Example

What we are going to do :     

A View with a Button. When we click that Button a fragment is being added dynamically in our View. We click again and the fragment is being dynamically removed.

before and after Fragment Transaction took place

What we need: 

One Activity and one Fragment. In the Activity's layout we add two layout objects. That's a Button and a FrameLayout.

In Fragment's layout we have a TextView that contains just text in a color background

So the code for the Activity's and Fragment's layout is: 

<?xml version="1.0" encoding="utf-8"?> <relativelayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <Button android:id="@+id/button_frag_1" android:layout_width="124dp" android:layout_height="wrap_content" android:text="@string/button_text_1" /> <FrameLayout android:id = "@+id/fragment_container_1" android:layout_width="80dp" android:layout_height="wrap_content" android:layout_alignBottom="@+id/button_frag_1" android:layout_alignParentRight="true" android:layout_alignParentTop="true" android:layout_toRightOf="@+id/button_frag_1" > </FrameLayout> </RelativeLayout>
Fragment's Layout : <?xml version="1.0" encoding="utf-8"?> <linearlayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:background="@color/cool"> <TextView android:id="@+id/tv" android:layout_width="fill_parent" android:layout_height="wrap_content" android:textColor="#FFCC99" android:gravity="center" android:text="Add/Remove Fragment" /> </LinearLayout>
 
Note the android:id = "@+id/fragment_container_1"  in the Activity's layout which is an identifier for our fragment. When we make Transactions like add we refer to a fragment by id.

Activity and Fragment :

Fragment Class :   is a typical Fragment class as we have seen it before
public class AddRemoveFragment extends Fragment { @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate( R.layout.addremove_fragment , container, false); return view; } }

Activity Class :  onClick() begins Transaction. If state is null then we add and commit the fragment else we need to remove and commit again.
So the code is :

public class AddRemoveActivity extends FragmentActivity { public int state=0; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.addremove_activity); final AddRemoveFragment Frag_A = new AddRemoveFragment(); final Button button = (Button) findViewById(R.id.button_frag_1); button.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { FragmentTransaction transaction = getSupportFragmentManager().beginTransaction(); if ( state == 0 ) { state=1; transaction.add(R.id.fragment_container_1, Frag_A); transaction.commit(); } else { state=0; transaction.remove(Frag_A); transaction.commit(); } } }); } }

ActionBar/ActionBarSherlock Tabs

Navigation Tabs:

ActionBar supports built-in Tabs or drop-down lists that you can use to change the Fragment is currently  visible. We are going to work with ActionBarSherlock library so we can have backwards compatibility.

Note 1 :  Either Tabs or drop-down lists but not both in ActionBar.

Note 2 :  Every Tab is associated with one Fragment. To change Fragments by using the Tabs,  perform a FragmentTransaction each time a Tab is selected.

Display Tabs :  

actionbar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); actionbar.setDisplayShowTitleEnabled(false);

Add Tabs :

You can add Tabs with the addTab() method. The first Tab added is the selected one therefore the visible.
Code is like below :

Tab tab = actionbar.newTab()                                .setText(R.string.text_tab_1)                                .setTabListener(new TabListener<myfragment>( this, "text", myFragment.class ) ); actionbar.addTab(tab);

Implement ActionBar.TabListener :

We 're going to split it into 3 parts :

1. First part the implementation of the Fragments.
2. Second part the implementation of ActionBar.TabListener 
3. Third part is to add the Tabs using the TabListener we created before.

The result we expect is the screenshot below :

1) Fragments 
Fragment class is just a basic Fragment class in which we only inflate the layout :

public class Fragment_1 extends Fragment { @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate( R.layout.fragment_1 , container, false); return view; //returns view } // ********** declare INTERFACE ***************** // }

And the corresponding XML layout :

<?xml version="1.0" encoding="utf-8"?> <linearlayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="center" android:orientation="vertical" > <textview android:id="@+id/textView1" android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="center" android:text="Tab 1"/> <button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Button" > </Button> </LinearLayout>

We repeat this process for Fragment_2.

2) TabListener 
TabListener's implementation is the most difficult part of the work.

public class TabListener<t extends Fragment> implements com.actionbarsherlock.app.ActionBar.TabListener { private final Activity mActivity; private final String mTag; private final Class<t> mClass; private Fragment mFragment; // Constructor ********* public TabListener(Activity activity, String tag, Class<t> cls) { mActivity = activity; mTag = tag; mClass = cls; } /* The following are each of the ActionBar.TabListener callbacks */ public void onTabSelected(Tab tab, FragmentTransaction ft) { // Check if the fragment is already initialized if (mFragment == null) { // If not, instantiate and add it to the activity mFragment = Fragment.instantiate(mActivity, mClass.getName()); ft.add(android.R.id.content, mFragment, mTag); //ft.add(android.R.id.content, mFragment, mTag); } else { // If it exists, simply attach it in order to show it ft.attach(mFragment); } } @Override public void onTabUnselected(Tab tab, FragmentTransaction ft) { if (mFragment != null) { // Detach the fragment, because another one is being attached ft.detach(mFragment); } } @Override public void onTabReselected(Tab tab, FragmentTransaction ft) { // TODO Auto-generated method stub } }

Our constructor is  public TabListener(Activity activity, String tag, Class<T> clz)  where activity is the host Activity, tag is the identifier Tag of the fragment and cls the Fragment's class so we can instantiate the fragment.

Callbacks in this Interface will handle the event. Specifically when a Tab is clicked then onTabSelected() will execute the Fragment transaction and add the fragment to the Activity.

In our case the Tab content will fill the activity's layout, so our activity doesn't needs a layout. Each fragment is placed in the default root ViewGroup, which we can refer to with the android.R.id.content ID.

3) MainActivity
Because we have to deal with Fragments our MainActivity  will extend FragmentActivity ( or just Activity for Android 3.0 and up ) but in our case with ActionBarSherlock will extend the SherlockFragmentActivity.



public class ABStest extends SherlockFragmentActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //setContentView(R.layout.activity_abstest); // no need for layout... ActionBar actionbar = getSupportActionBar(); actionbar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); actionbar.addTab(actionbar.newTab() .setText("TAB 1") .setTabListener(new TabListener<fragment_1>(this, "tab1", Fragment_1.class))); actionbar.addTab(actionbar.newTab() .setText("TAB 2") .setTabListener(new TabListener<fragment_2>(this, "tab2", Fragment_2.class))); } }

All we are doing here is to get the ActionBar item, and add Tabs with the addTab() method.
We set a TabListener for each Tab by calling the setTabListener().
Also we set the tab's title and/or icon with setText() and/or setIcon().

That's all ! Check all the code and/or fork the project from github here so you can see by yourself how it works. 

Simple Fragment Transactions

What we are going to do here is a simple Activity with a button. When we click that button a Fragment Transaction takes place and we add the Fragment's layout.

1. You start a new Project and you are using support library if you target API less than 11. So first add the support lib to the project.

2. In my case I'm extending FragmentActivity ( i'm using minimum sdk version 8  ) or for API 11 and above you can use just Activity.

3.  First we are going to create the Fragment.

We extend Fragment class, inflate Fragment's layout at onCreateView() method and declare an Interface for future communication between Fragment and Activity.
So our code is here :


public class Fragment_A extends Fragment {

protected static final String TAG = "FRAGMENTS_A";
private CallbackInterface listener;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_a_layout, container, false);

        return view; //returns view
    }
 
    // ********** declare INTERFACE ***************** //
 
    public interface CallbackInterface {
    public void onSomethingSelected(int position);
      }      

 
    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
     
        // This makes sure that the container activity has implemented the callback interface. If not, it throws an exception
        try {
            listener = (CallbackInterface) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()
                    + " must implement CallbackInterface");
        }
    }
 
 
}

4. Fragment's layout 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" 
    android:background="@color/cool">
    
    <TextView
        android:id="@+id/tv"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Fragment A" />
</LinearLayout>

5. Now we are going to create our Activity :


public class MainActivity extends FragmentActivity  implements CallbackInterface  {

private static final String TAG = "passNumberTAG";

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);


final Button button = (Button) findViewById(R.id.button_id);
    button.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
         
       Fragment_A Frag_A = new Fragment_A();
         
       FragmentManager fm1 = getSupportFragmentManager();
        FragmentTransaction transaction = fm1.beginTransaction();
            
        transaction.add(R.id.fragment_container, Frag_A);
        transaction.commit();
            
        }
    });

}

@Override
public void onSomethingSelected(int position) {
Log.d(TAG, "Give me the result  " + position  );
position = position +1;
Log.d(TAG, "Give me the result  " + position  );

}

}

The part where the Transaction takes place is inside the click listener : 
        Fragment_A Frag_A = new Fragment_A();
          
        FragmentManager fm1 = getSupportFragmentManager();
        FragmentTransaction transaction = fm1.beginTransaction();
             
        transaction.add(R.id.fragment_container, Frag_A);
        transaction.commit();

-> new Fragment -> get FragmentManager -> beginTransaction -> add new layout and commit.


One last thing is the Activity's layout. The activity's layout includes an empty FrameLayoutthat acts as the fragment container. 



<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

        <Button 
         android:id="@+id/button_id"
         android:layout_height="wrap_content"
    android:layout_width="wrap_content"
    android:text="@string/button_text" />

        
        <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/fragment_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />
        
        
</RelativeLayout>

ActionBarSherlock configuration

1.
I'm creating a custom Theme, let's call it TestABS with parent the HOLO Theme ( in our case Sherlock ).
So now in my styles.xml I add the line :
<style name="Theme.TestABS" parent="@style/Theme.Sherlock"></style> 

2.
Later I'll edit Manifest file like this :

<activity
      android:name=".MainActivity"
      android:label="@string/app_name"
      android:theme="@style/Theme.TestABS"
      android:logo="@drawable/ad_logo">

3.
When Activity starts, the system adds ActionBar and the overflow menu by calling onCreateOptionsMenu().
This method inflates an XML resource which defines the menu items. This files is in the folder /res/menu. In those items on the XML file I have to add the android:showAsAction keyword, so now the items will appear as Action Items in my ActionBar and not Options Menu.

So a simple item should be like :

    <item
        android:id="@+id/menu_settings"
        android:orderInCategory="100"
        android:showAsAction="ifRoom"
        android:title="Text Here" />



This works as long as I have an ActionBar in my Activity( When do I have an ActionBar ? When I add   android:theme="@style/Theme.HOLO" in my manifest file for android 3.0 and greater. For lower versions I need Theme.Sherlock . In both cases I can declare mine custom theme like I did above with TestABS ).


Links :
1) Adding ActionBarSherlock to your Project
2) Adding Items to the ActionBar 
3) The Overflow menu ( As a rule of thumb you should always use ifRoom, if you want the icon to be part of your action bar and you should use never if you want the item to always be part of the overflow menu. )

Add Marker to Google Map

To detect a long map click by the user, so add a new Marker, we need to implement OnMapLongClickListener Interface.

Then we set our map to listen for any calls when its long pressed :    mMap.setOnMapLongClickListener(this);

And now in our code we can add a new Marker every time the user long clicks the map :

mMap.addMarker(new MarkerOptions().position(point));

Detect user click on Map

To detect click on GoogleMap we implement OnMapClickListener Interface.
We add to our GoogleMap setOnMapClickListener . This sets a callback to the Interface when the map is clicked

Then we need to override the onMapClick(LatLng point) 


@Override 
public void onMapClick(LatLng point) { mMap.animateCamera(CameraUpdateFactory.newLatLng(point)); }

We are using CameraUpdateFactory to get a new CameraUpdate Object ( an object to modify a map's camera ) and animate to the new point with animateCamera.