Monday, February 4, 2013

Android beginner tutorial: Part 72 - Editing contacts

In this tutorial we'll make it possible to select and edit contacts in the database.

First of all, declare 2 new variables - editDialog and cursor:

private AlertDialog editDialog;
private Cursor cursor;

Now go to updateList() and instead of declaring a new Cursor each time, reuse the cursor variable:

public void updateList(){
String[] columns = new String[] {myDbHelper._ID, myDbHelper.NAME, myDbHelper.PHONE};
ContentResolver resolver = getContentResolver();
cursor = resolver.query(CONTENT_URI, columns, null, null, null);

final ListAdapter adapter = new SimpleCursorAdapter(this, R.layout.customrow, cursor, new String[] {myDbHelper.NAME, myDbHelper.PHONE}, new int[] {R.id.t_name, R.id.t_phone}, 0);
ListView list = (ListView)findViewById(R.id.contactList);
list.setAdapter(adapter);
}

Another change we'll make is move all the code that creates the "Add contact" dialog into the dialogAdd() function:

public void dialogAdd(){
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

LayoutInflater inflater = LayoutInflater.from(getApplicationContext());
alertView = inflater.inflate(R.layout.add_window, null);
builder.setView(alertView);

builder.setTitle("Add contact");

builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
EditText t_name = (EditText)alertView.findViewById(R.id.inp_name);
EditText t_phone = (EditText)alertView.findViewById(R.id.inp_phone);
String new_name = t_name.getText().toString();
String new_phone = t_phone.getText().toString();
ContentValues values = new ContentValues();
values.put(myDbHelper.NAME, new_name);
values.put(myDbHelper.PHONE, new_phone);
getContentResolver().insert(CONTENT_URI, values);
updateList();
}
});

builder.setCancelable(true);
addDialog = builder.create();

addDialog.show();
}

Now go to onCreate() function and add an OnItemClickListener listener to our list. Call dialogEdit() function when an item is selected. It is important to pass 2 values as parameters to that function, those are the position and id of the current item.

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

ListView list = (ListView)findViewById(R.id.contactList);
list.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
dialogEdit(position, id);
}
});

updateList();
}

Create the dialogEdit() function. Create an AlertDialog just like it was done with the "Add contact" window. Instead of using the insert() method of your ContentResolver, use update(). Moreover, we need to set the default values of the text fields when the window is opened. This can be done using the position value we receive as one of the parameters and the cursor object:

public void dialogEdit(final int position, final long id){
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

LayoutInflater inflater = LayoutInflater.from(getApplicationContext());
alertView = inflater.inflate(R.layout.add_window, null);
builder.setView(alertView);

builder.setTitle("Edit contact");

builder.setPositiveButton("Save", new DialogInterface.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
EditText t_name = (EditText)alertView.findViewById(R.id.inp_name);
EditText t_phone = (EditText)alertView.findViewById(R.id.inp_phone);
String new_name = t_name.getText().toString();
String new_phone = t_phone.getText().toString();
ContentValues values = new ContentValues();
values.put(myDbHelper.NAME, new_name);
values.put(myDbHelper.PHONE, new_phone);
getContentResolver().update(CONTENT_URI, values, myDbHelper._ID+"="+id, null);
updateList();
}
});

builder.setCancelable(true);

EditText t_name = (EditText)alertView.findViewById(R.id.inp_name);
EditText t_phone = (EditText)alertView.findViewById(R.id.inp_phone);
cursor.moveToPosition(position);
t_name.setText(cursor.getString(1));
t_phone.setText(cursor.getString(2));

editDialog = builder.create();
editDialog.show();
}

Full code so far:

package com.kircode.codeforfood_test;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.DialogInterface;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.widget.SimpleCursorAdapter;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.EditText;
import android.widget.ListAdapter;
import android.widget.ListView;

public class MainActivity extends Activity{

private static final Uri CONTENT_URI = Uri.parse("content://com.kircode.codeforfood_test.mycontentprovider/contacts");
private static final int IDM_ADD = 101;

private AlertDialog addDialog;
private AlertDialog editDialog;
private View alertView;
private Cursor cursor;

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

ListView list = (ListView)findViewById(R.id.contactList);
list.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
dialogEdit(position, id);
}
});

updateList();
}

@Override
public boolean onCreateOptionsMenu(Menu menu){
menu.add(Menu.NONE, IDM_ADD, Menu.NONE, "Add");
return(super.onCreateOptionsMenu(menu));
}

@Override
public boolean onOptionsItemSelected(MenuItem item){
switch(item.getItemId()){
case IDM_ADD:
dialogAdd();
break;
}
return(super.onOptionsItemSelected(item));
}

public void dialogAdd(){
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

LayoutInflater inflater = LayoutInflater.from(getApplicationContext());
alertView = inflater.inflate(R.layout.add_window, null);
builder.setView(alertView);

builder.setTitle("Add contact");

builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
EditText t_name = (EditText)alertView.findViewById(R.id.inp_name);
EditText t_phone = (EditText)alertView.findViewById(R.id.inp_phone);
String new_name = t_name.getText().toString();
String new_phone = t_phone.getText().toString();
ContentValues values = new ContentValues();
values.put(myDbHelper.NAME, new_name);
values.put(myDbHelper.PHONE, new_phone);
getContentResolver().insert(CONTENT_URI, values);
updateList();
}
});

builder.setCancelable(true);
addDialog = builder.create();

addDialog.show();
}

public void dialogEdit(final int position, final long id){
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

LayoutInflater inflater = LayoutInflater.from(getApplicationContext());
alertView = inflater.inflate(R.layout.add_window, null);
builder.setView(alertView);

builder.setTitle("Edit contact");

builder.setPositiveButton("Save", new DialogInterface.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
EditText t_name = (EditText)alertView.findViewById(R.id.inp_name);
EditText t_phone = (EditText)alertView.findViewById(R.id.inp_phone);
String new_name = t_name.getText().toString();
String new_phone = t_phone.getText().toString();
ContentValues values = new ContentValues();
values.put(myDbHelper.NAME, new_name);
values.put(myDbHelper.PHONE, new_phone);
getContentResolver().update(CONTENT_URI, values, myDbHelper._ID+"="+id, null);
updateList();
}
});

builder.setCancelable(true);

EditText t_name = (EditText)alertView.findViewById(R.id.inp_name);
EditText t_phone = (EditText)alertView.findViewById(R.id.inp_phone);
cursor.moveToPosition(position);
t_name.setText(cursor.getString(1));
t_phone.setText(cursor.getString(2));

editDialog = builder.create();
editDialog.show();
}

public void updateList(){
String[] columns = new String[] {myDbHelper._ID, myDbHelper.NAME, myDbHelper.PHONE};
ContentResolver resolver = getContentResolver();
cursor = resolver.query(CONTENT_URI, columns, null, null, null);

final ListAdapter adapter = new SimpleCursorAdapter(this, R.layout.customrow, cursor, new String[] {myDbHelper.NAME, myDbHelper.PHONE}, new int[] {R.id.t_name, R.id.t_phone}, 0);
ListView list = (ListView)findViewById(R.id.contactList);
list.setAdapter(adapter);
}

}

Thanks for reading!

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