How to view the fragment correctly

Question

I am currently in the lab and I am getting a weird error. Everything compiles fine, and the application works fine, but when I click on the name, it shows the twitter channel, but also shows the names of people, as when overlaying one view on top of another.

Here is my code for MainActivity:

package course.labs.fragmentslab;

import android.app.Activity;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends Activity implements
    FriendsFragment.SelectionListener {

private static final String TAG = "Lab-Fragments";

private FriendsFragment mFriendsFragment;
private FeedFragment mFeedFragment;

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

    // If the layout is single-pane, create the FriendsFragment 
    // and add it to the Activity

    if (!isInTwoPaneMode()) {

        mFriendsFragment = new FriendsFragment();

        //TODO 1 - add the FriendsFragment to the fragment_container
        FragmentManager fragM = getFragmentManager();
        FragmentTransaction fragT = fragM.beginTransaction();
        fragT.add(R.id.fragment_container, mFriendsFragment);
        fragT.commit();



    } else {

        // Otherwise, save a reference to the FeedFragment for later use

        mFeedFragment = (FeedFragment) getFragmentManager()
                .findFragmentById(R.id.feed_frag);
    }

}

// If there is no fragment_container ID, then the application is in
// two-pane mode

private boolean isInTwoPaneMode() {

    return findViewById(R.id.fragment_container) == null;

}

// Display selected Twitter feed

public void onItemSelected(int position) {

    Log.i(TAG, "Entered onItemSelected(" + position + ")");

    // If there is no FeedFragment instance, then create one

    if (mFeedFragment == null)
        mFeedFragment = new FeedFragment();

    // If in single-pane mode, replace single visible Fragment

    if (!isInTwoPaneMode()) {

        //TODO 2 - replace the fragment_container with the FeedFragment

        FragmentManager fragM = getFragmentManager();
        FragmentTransaction fragT = fragM.beginTransaction();
        fragT.add(R.id.fragment_container ,mFeedFragment);
        fragT.commit(); 



        // execute transaction now
        getFragmentManager().executePendingTransactions();

    }

    // Update Twitter feed display on FriendFragment
    mFeedFragment.updateFeedDisplay(position);

 }
}

Here is the corresponding XML file:

<?xml version="1.0" encoding="utf-8"?>
<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" /

As I said, everything works fine, but the activity saves one fragment, and then displays another fragment.

I have no idea why.

Answer 1

You need to replace the fragment, not add a new one. It must be done inonItemSelected

fragT.replace(R.id.fragment_container ,mFeedFragment);

I myself made the same mistake ;-) Good luck!

Answer 2

, :

…
fragT.remove(mFriendsFragment);
fragT.add(R.id.fragment_container, mFeedFragment);
fragT.commit();

, "replace" , .