I am making a simple Notepad app and have an issue displaying the data in the listview when the return button is pressed on the emulator to go back to the MainActivity where the list is displayed. It only displays the data when I close the app and open it again, then the listview is populated. I have shown my code below.
This my MainActivity where the ListView is present:
package example.mynotepad;
import example.mynotepad.R;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
public class MainActivity extends Activity implements OnItemClickListener {
Button Add_Btn;
ListView nListView;
NotesAdapter nAdapter;
Cursor nCursor;
public static boolean isDbCreated = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Add_Btn = (Button) findViewById(R.id.add_btn);
Add_Btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent AddNotes = new Intent(MainActivity.this, AddNotes.class);
startActivity(AddNotes);
}
});
nListView = (ListView) findViewById(R.id.listView1);
final NotesDbHelper nHelper = new NotesDbHelper(this);
nHelper.Open();
new Handler().post(new Runnable() {
@Override
public void run() {
nCursor = nHelper.AllData();
nAdapter = new NotesAdapter(MainActivity.this, nCursor);
nListView.setAdapter(nAdapter);
}
});
nListView.setOnItemClickListener(this);
nListView.setOnItemLongClickListener(new OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> arg0, View v,
int position, long arg3) {
// TODO Auto-generated method stub
TextView id = (TextView) v.findViewById(R.id.textView1);
final int i = Integer.parseInt(id.getText().toString());
AlertDialog.Builder aDialog = new AlertDialog.Builder(
MainActivity.this);
aDialog.setTitle("Delete Note?");
aDialog.setMessage("This Will Delete It Permanently?");
aDialog.setPositiveButton((getString(R.string.Delete)),
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface Dialog,
int which) {
nHelper.Delete(i); // Delete Method in DBHelper
nCursor.requery();
nAdapter.notifyDataSetChanged();
nListView.setAdapter(nAdapter);
}
});
aDialog.setNegativeButton((getString(R.string.Cancel)),
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog,
int which) {
// TODO Auto-generated method stub
dialog.dismiss();
}
});
aDialog.show();
return false;
}
});
}
@Override
public void onItemClick(AdapterView<?> arg0, View view, int position,
long arg3) {
TextView noteid = (TextView) view.findViewById(R.id.textView1);
TextView notetitle = (TextView) view.findViewById(R.id.textView2);
TextView notebody = (TextView) view.findViewById(R.id.textView3);
int i = Integer.parseInt(noteid.getText().toString());
String nt = notetitle.getText().toString();
String nb = notebody.getText().toString();
Intent Update = new Intent(MainActivity.this, UpdateNotes.class);
Update.putExtra("id", i);
Update.putExtra("ntitle", nt);
Update.putExtra("nbody", nb);
startActivityForResult(Update, 101);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK) {
switch (requestCode) {
case 101:
nCursor.requery();
nAdapter.notifyDataSetChanged();
nListView.setAdapter(nAdapter);
break;
}
}
}
}
MainActivity XML:
<LinearLayout xmlns:tools="http://schemas.android.com/tools"
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<Button
android:id="@+id/add_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginBottom="15dp"
android:layout_marginTop="15dp"
android:text="@string/add_note_btn" />
<ListView
android:id="@+id/listView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fastScrollEnabled="true"
android:focusable="false"
android:focusableInTouchMode="false"
android:splitMotionEvents="true" >
</ListView>
</LinearLayout>
This is the Activity to Add Notes:
package example.mynotepad;
import example.mynotepad.R;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class AddNotes extends Activity {
Button Cancel_Btn, Save_Btn;
EditText ET_Title, ET_Notes;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_notes);
Cancel_Btn = (Button) findViewById(R.id.cancel_btn);
Save_Btn = (Button) findViewById(R.id.save_btn);
ET_Title = (EditText) findViewById(R.id.et_title);
ET_Notes = (EditText) findViewById(R.id.et_notes);
final NotesDbHelper Helper = new NotesDbHelper(AddNotes.this);
Save_Btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (ET_Title.getText().toString().trim().equals("")) {
Toast.makeText(getApplicationContext(), "Title Required",
Toast.LENGTH_SHORT).show();
} else if (ET_Notes.getText().toString().trim().equals("")) {
Toast.makeText(getApplicationContext(),
"Don't Forget To Type A Note", Toast.LENGTH_SHORT)
.show();
} else {
boolean Added = true;
try {
String NoteTitle = ET_Title.getText().toString();
String NoteBody = ET_Notes.getText().toString();
Helper.Open();
Helper.AddNote(NoteTitle, NoteBody);
} catch (Exception e) {
Added = false;
e.printStackTrace();
}
finally {
if (Added) {
Toast toast = Toast.makeText(AddNotes.this, "Note Added Successfully", Toast.LENGTH_LONG);
toast.show();
}
Helper.Close();
ET_Title.setText("");
ET_Notes.setText("");
}
}
}
});
Cancel_Btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
finish();
}
});
}
}
Add Notes XML:
<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="${relativePackage}.${activityClass}" >
<TextView
android:id="@+id/tv_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/tv_title"
android:textAppearance="?android:attr/textAppearanceLarge" />
<EditText
android:id="@+id/et_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="20dp"
android:ems="10"
android:inputType="textCapWords" />
<TextView
android:id="@+id/tv_note"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/tv_note"
android:textAppearance="?android:attr/textAppearanceLarge" />
<EditText
android:id="@+id/et_notes"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="top"
android:layout_marginBottom="40dp"
android:ems="10"
android:inputType="textCapSentences|textMultiLine" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<Button
android:id="@+id/cancel_btn"
android:layout_width="80dp"
android:layout_height="wrap_content"
android:layout_marginLeft="160dp"
android:text="@string/cancel_note_btn" />
<Button
android:id="@+id/save_btn"
android:layout_width="80dp"
android:layout_height="wrap_content"
android:text="@string/save_note_btn" />
</LinearLayout>
</LinearLayout>
Activity to UpdateNotes
package example.mynotepad;
import example.mynotepad.R;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class UpdateNotes extends Activity {
NotesDbHelper nHelper;
Button UpdateBtn, CancelBtn;
EditText nTitle, nBody;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.update_notes);
UpdateBtn = (Button) findViewById(R.id.update_btn);
CancelBtn = (Button) findViewById(R.id.Ucancel_btn);
nTitle = (EditText) findViewById(R.id.Uet_title);
nBody = (EditText) findViewById(R.id.Uet_notes);
Intent intent = getIntent();
Bundle mods = intent.getExtras();
final int id = mods.getInt("id");
String ntitle = mods.getString("ntitle");
String nbody = mods.getString("nbody");
nTitle.setText(ntitle);
nBody.setText(nbody);
UpdateBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
nHelper = new NotesDbHelper(UpdateNotes.this);
nHelper.Open();
String nt = nTitle.getText().toString();
String nb = nBody.getText().toString();
nHelper.Update(id, nt, nb);
nHelper.Close();
Intent display = new Intent(UpdateNotes.this,
MainActivity.class);
setResult(RESULT_OK, display);
finish();
Toast.makeText(getApplicationContext(), "Update Successful",
Toast.LENGTH_SHORT).show();
}
});
CancelBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent = new Intent(UpdateNotes.this, MainActivity.class);
startActivity(intent);
}
});
}
}
NotesAdapter:
package example.mynotepad;
import example.mynotepad.R;
import android.annotation.SuppressLint;
import android.content.Context;
import android.database.Cursor;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CursorAdapter;
import android.widget.TextView;
public class NotesAdapter extends CursorAdapter {
public NotesAdapter(Context context, Cursor c) {
super(context, c);
// TODO Auto-generated constructor stub
}
public void bindView(View view, Context context, Cursor cursor) {
TextView noteID = (TextView) view.findViewById(R.id.textView1);
TextView noteTITLE = (TextView) view.findViewById(R.id.textView2);
TextView noteBODY = (TextView) view.findViewById(R.id.textView3);
noteID.setText(cursor.getString(cursor.getColumnIndex(cursor.getColumnName(0))));
noteTITLE.setText(cursor.getString(cursor.getColumnIndex(cursor.getColumnName(1))));
noteBODY.setText(cursor.getString(cursor.getColumnIndex(cursor.getColumnName(2))));
}
@SuppressLint("InflateParams")
public View newView(Context context, Cursor cursor, ViewGroup parent) {
LayoutInflater mInflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View View = mInflater.inflate(R.layout.list, null);
return View;
}
protected void onContentChanged() {
// TODO Auto-generated method stub
super.onContentChanged();
notifyDataSetChanged();
}
}
NotesDbHelper:
package example.mynotepad;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class NotesDbHelper {
public static final String DATABASE_NAME = "NotesDB.db";
public static final int version = 1;
public static final String Notes_Table = "Notes";
public static final String Note_ID = "_id";
public static final String NoteTitle = "NoteTitle";
public static final String NoteBody = "NoteBody";
private SQLiteDatabase nDatabase;
public Context Context;
public NotesDbHelper(Context c) {
Context = c;
}
private class DatabaseHelper extends SQLiteOpenHelper {
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, version);
}
@Override
public void onCreate(SQLiteDatabase Database) {
Database.execSQL("create table " + Notes_Table + " ( " + Note_ID
+ " INTEGER PRIMARY KEY AUTOINCREMENT , " + NoteTitle
+ " TEXT NOT NULL ," + NoteBody + " TEXT NOT NULL);");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
public NotesDbHelper Open() throws SQLException {
DatabaseHelper nDatabaseHelper = new DatabaseHelper(Context);
nDatabase = nDatabaseHelper.getWritableDatabase();
return this;
}
public void Close() {
nDatabase.close();
}
public long AddNote(String noteTitle, String noteBody) {
// TODO Auto-generated method stub
ContentValues cv = new ContentValues();
cv.put(NoteTitle, noteTitle);
cv.put(NoteBody, noteBody);
return nDatabase.insertOrThrow(Notes_Table, null, cv);
}
public Cursor AllData() {
// TODO Auto-generated method stub
String[] all = new String[] { Note_ID, NoteTitle, NoteBody };
Cursor cursor = nDatabase.query(Notes_Table, all, null, null, null,
null, null);
return cursor;
}
public void Update(int id, String nt, String nb) {
// TODO Auto-generated method stub
ContentValues cv = new ContentValues();
cv.put(NoteTitle, nt);
cv.put(NoteBody, nb);
nDatabase.update(Notes_Table, cv, Note_ID + " = " + id, null);
}
public void Delete(int i) {
// TODO Auto-generated method stub
nDatabase.delete(Notes_Table, Note_ID + " = " + i, null);
}
}
This is the List 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"
android:orientation="vertical" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="20sp" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="20sp" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="20sp" />
</LinearLayout>
I have looked over my code several times and it looks fine. Probably it is something very simple that I cannot see, I don't know. Any help would really be appreciated. Thanks in advance.
