I'm would like to make my Android application use Fragment Transactions, so that I can switch between various Fragments display their associated lists. My application worked fine prior to attempting to convert to just Fragment Transactions. In my initial activity_main.xml, I removed the android:name="com.birdsall.peter.chap.ChapterFragment", it is my understanding you can't use xml defined fragments with fragment transactions.
1) I can't seem to get the .add() within
getSupportFragmentManager correct with it's parameters, even with code from a working example.
I have also attempted to use the newer version of FragmentTransactions to no avail.
I even took a working example of code using getSupportFragmentManager / FragmentTransactions,
modified to use the names I had, it worked. I then imported that code into my application
and it fails on the .add() syntax. I'm somewhat new to Android development and can't
pinpoint where I'm going wrong.
Here is my main xml layout for the FrameLayout
activity_main.xml
<?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" >
<FrameLayout
android:id="@+id/fragment_container"
android:layout_width="0dip"
android:layout_height="match_parent"
android:layout_weight="1" />
<fragment
android:id="@+id/chapterfragments"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<!-- Removed this from above <fragment> block to enable Fragment Transaction
android:name="com.birdsall.peter.chap.ChapterFragment" -->
</LinearLayout>
Here is the xml layout for the ChapterFragment ListView
chapterfragment.xml
<?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" >
<ListView android:id="@+id/chapterlist" android:layout_width="match_parent"
android:layout_height="wrap_content" android:layout_alignParentLeft="true" />
</RelativeLayout>
Here is the layout for the details of the list chapter_info.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:orientation="vertical" android:padding="6dip">
<TextView android:id="@+id/chapter1" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:layout_alignParentTop="true"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView android:id="@+id/textViewLiteral" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:layout_alignParentTop="true"
android:layout_toRightOf="@+id/chapter1" android:text=" - "
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView android:id="@+id/chaptertitle1" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:layout_alignParentTop="true"
android:layout_toRightOf="@+id/textViewLiteral"
android:textAppearance="?android:attr/textAppearanceSmall" />
</RelativeLayout>
Here is the MainActivity.java that I have modified. I left the 'setContentView(R.layout.activity_main);' as I thought I needed to create a view (even though it empty) to add the fragment view to.
package com.birdsall.peter.chap;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
public class MainActivity extends FragmentActivity implements ChapterFragment.ChapterSelectedListener {
private static final String TAG = "Main_Activity";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.i(TAG, "Starting ...");
setContentView(R.layout.activity_main);
if (findViewById(R.id.fragment_container) != null) {
if (savedInstanceState != null) {
return;
}
// Create an instance of ExampleFragment
ChapterFragment firstFragment = new ChapterFragment();
// Add the fragment to the 'fragment_container' FrameLayout
getSupportFragmentManager().beginTransaction()
**.add**(R.id.fragment_container, firstFragment).commit();
Log.i(TAG, "Ending ...");
}
} ...
Here is my ChapterFragment.java
package com.birdsall.peter.chap;
import android.app.Activity;
import android.app.Fragment;
import android.app.LoaderManager;
import android.content.CursorLoader;
import android.content.Loader;
import android.database.Cursor;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.Toast;
public class ChapterFragment extends Fragment implements LoaderManager.LoaderCallbacks<Cursor> {
ChapterSelectedListener mCallback;
// Container Activity must implement this interface
public interface ChapterSelectedListener {
public void onChapterSelected(String position, int rowId);
}
public SimpleCursorAdapter dataAdapter;
private static final String TAG = "ChapterFragment";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState ) {
View listview = inflater.inflate(R.layout.activity_main,null);
ListView mList =(ListView)listview.findViewById(R.id.chapterlist);
// The desired columns to be bound
String[] columns = new String[] {
TDAdb.COL_CHAPTER,
TDAdb.COL_CHAPTERTITLE};
// the XML defined views which the data will be bound to
int[] to = new int[] {
R.id.chapter1,
R.id.chaptertitle1,
};
// create an adapter from the SimpleCursorAdapter
dataAdapter = new SimpleCursorAdapter(
getActivity(),
R.layout.chapter_info,
null,
columns,
to,
0);
mList.setAdapter(dataAdapter);
//Ensures a loader is initialized and active.
getLoaderManager().initLoader(0, null, this);
return listview;
}
@Override
public void onStart() {
super.onStart();
Log.i(TAG, " onStart");
displayListView();
Log.i(TAG, " end of onStart");
}
@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 {
mCallback = (ChapterSelectedListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement ChapterSelectedListener");
}
}
@Override
public void onResume() {
super.onResume();
//Starts a new or restarts an existing Loader in this manager
Log.i(TAG, " onResume");
getLoaderManager().restartLoader(0, null, this);
}
private void displayListView() {
Log.i(TAG, " Starting displayListView");
// The desired columns to be bound
String[] columns = new String[] {
TDAdb.COL_CHAPTER,
TDAdb.COL_CHAPTERTITLE};
// the XML defined views which the data will be bound to
int[] to = new int[] {
R.id.chapter1,
R.id.chaptertitle1,
};
// create an adapter from the SimpleCursorAdapter
dataAdapter = new SimpleCursorAdapter(
getActivity(),
R.layout.chapter_info,
null,
columns,
to,
0);
// get reference to the ListView
ListView listView = (ListView) getView().findViewById(R.id.chapterlist);
// Assign adapter to ListView
listView.setAdapter(dataAdapter);
//Ensures a loader is initialized and active.
getLoaderManager().initLoader(0, null, this);
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> listView, View view,
int position, long id) {
// Get the cursor, positioned to the corresponding row in the result set
Cursor cursor = (Cursor) listView.getItemAtPosition(position);
String chaptervalueselected =
cursor.getString(cursor.getColumnIndexOrThrow(TDAdb.COL_CHAPTER));
mCallback.onChapterSelected(chaptervalueselected, position);
Toast.makeText(getActivity(), "Chapter " + chaptervalueselected, Toast.LENGTH_SHORT).show();
// starts a new Intent to update/delete a Chapter
// pass in row Id to create the Content URI for a single row
//Intent chapterEdit = new Intent(getBaseContext(), ChapterEdit.class);
//Bundle bundle = new Bundle();
//bundle.putString("mode", "update");
//bundle.putString("rowId", rowId);
//chapterEdit.putExtras(bundle);
//startActivity(chapterEdit);
}
});
}
// This is called when a new Loader needs to be created.
@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
Log.i(TAG, " onCreateLoader");
String[] projection = {
TDAdb.KEY_ROWID,
TDAdb.COL_CHAPTER,
TDAdb.COL_CHAPTERTITLE};
CursorLoader cursorLoader = new CursorLoader(getActivity(),
TDAProvider.CONTENT_URI, projection, null, null, null);
return cursorLoader;
}
@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
Log.i(TAG, " ononLoadFinished");
// Swap the new cursor in. (The framework will take care of closing the
// old cursor once we return.)
dataAdapter.swapCursor(data);
}
@Override
public void onLoaderReset(Loader<Cursor> loader) {
// This is called when the last Cursor provided to onLoadFinished()
// above is about to be closed. We need to make sure we are no
// longer using it.
Log.i(TAG, " onLoaderReset");
dataAdapter.swapCursor(null);
}
}
