How to update and delete the list View data in SQLite database with click listener?

Question

I am a beginner with SQLite Database. I have a problem with Update And Delete data from listView. I insert my data in listView when I click my listView data it will go in the UpdateActivity. Now I want To get those listView selected value in the new UpdateActivity so that I can edit or delete. How to do that.

ListDataActivity.Java

public  void loadData() {
                //Create an arraylist so that i can load the data to add in the  arraylist
                ArrayList<String> listData = new ArrayList<>();

                Cursor cursor = databaseHelper.showAllData();

        if (cursor.getCount() == 0) {
            Toast.makeText(getApplicationContext(), "no data is available", Toast.LENGTH_LONG).show();
        } else {
            while (cursor.moveToNext()) {
                listData.add(cursor.getString(1) + " \t " + cursor.getString(2));
            }
        }
                    
                ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.list_item, R.id.textViewId, listData);
                listView.setAdapter(adapter);

                listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
                String selectedValue = adapterView.getItemAtPosition(position).toString();

                Toast.makeText(getApplicationContext(), "Selected Value : " + selectedValue, 
               Toast.LENGTH_LONG).show();
                Intent intent = new Intent(ListDataActivity.this,UpdateActivity.class);
                startActivity(intent);

            }
        });

UpdateActivity.Java

private DatabaseHelper databaseHelper;
    private String selectedName;
    private String selectedID;

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


        databaseHelper = new DatabaseHelper(this);
        SQLiteDatabase sqLiteDatabase = databaseHelper.getWritableDatabase();

        Intent receiveIntent = getIntent();

        selectedID = receiveIntent.getStringExtra("name");

        selectedName = receiveIntent.getStringExtra("surName");

When I insert data then I click on my list it goes into this type of design update activity. I want the Clicked Listview Data in the UpdateActivity. How can I solve that?

Answer 1

Now I want To get those listview selected value in the new UpdateActity so that I can edit or delete. How to do that.

Here's a working example that updates (goes to UpdateActivity) and deletes (on Long Click of an Item). This uses a CursorAdapter, namely the stock SimpleCursorAdapter. Using Cursor adapters for SQLite data is pretty simple.

First the DatabaseHelper :-

class DatabaseHelper extends SQLiteOpenHelper {
    public DatabaseHelper(@Nullable Context context) {
        super(context, "mydatabase", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        sqLiteDatabase.execSQL("CREATE TABLE IF NOT EXISTS mytable (_id INTEGER PRIMARY KEY, name TEXT, surname TEXT, phone TEXT)");
        /* Add some test data */
        add("Fred","Bloggs","0000000000",sqLiteDatabase);
        add("Jane","Doe","1111111111",sqLiteDatabase);
        add("Mary","Johnston","2222222222",sqLiteDatabase);
        add("Tom","cobboly","3333333333",sqLiteDatabase);
        add("Anne","Walker","4444444444",sqLiteDatabase);

    }

    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {

    }

    public long update(long id, String name, String surname, String phone) {
        long rv = 0;
        ContentValues cv = new ContentValues();
        if (name != null && name.length() > 0) cv.put("name",name);
        if (surname != null && surname.length() > 0) cv.put("surname",surname);
        if (phone != null && phone.length() > 0) cv.put("phone",phone);
        if (cv.size() > 0) rv = this.getWritableDatabase().update("mytable",cv,"_id=?",new String[]{String.valueOf(id)});
        return rv;
    }

    public long delete(long id) {
        return this.getWritableDatabase().delete("mytable","_id=?",new String[]{String.valueOf(id)});
    }

    public Cursor getAll() {
        return this.getWritableDatabase().query("mytable",null,null,null,null,null,null);
    }

    public Cursor getById(long id) {
        return this.getWritableDatabase().query("mytable",null,"_id=?",new String[]{String.valueOf(id)},null,null,null);
    }

    private long add(String name, String surname, String phone, SQLiteDatabase db) {
        ContentValues cv = new ContentValues();
        cv.put("name",name);
        cv.put("surname",surname);
        cv.put("phone",phone);
        return db.insert("mytable",null,cv);
    }

    public long add(String name, String surname, String phone) {
        return add(name,surname,phone,this.getWritableDatabase());
    }
}

• IMPORTANT NOTE Cursor adapters require an id column and that it be named _id.
• NOTE this adds some testing data.
• All access methods are included
  • getAll returns a Cursor with ALL rows from the table.
  • update updates according to the values passed, it caters for only updating the values (e.g. as there is no editSurname EditText, null is passed so the surname stays as it was.)
  • getById returns a cursor with all values according to the id
  • add without the 4th parameter is the typical add, the one with the 4th parameter is to allow it's use in onCreate before the DatabaaeHelper has been fully instantiated.

ListDataActivity

public class ListDataActivity extends AppCompatActivity {

    ListView listview;
    SimpleCursorAdapter sca;
    DatabaseHelper databaseHelper;
    Cursor cursor;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listview = this.findViewById(R.id.mylistview);
        databaseHelper = new DatabaseHelper(this);
        setOrRefreshListView();
    }

    /* handles the ListView */
    private void setOrRefreshListView() {
        cursor = databaseHelper.getAll(); /* Gets the data to be listed */
        /* If first time then setup the adapter listeners etc */
        if (sca == null) {
            sca = new SimpleCursorAdapter(
                    this,
                    android.R.layout.simple_expandable_list_item_2,
                    cursor,
                    new String[]{"name","phone"},
                    new int[]{android.R.id.text1, android.R.id.text2},
                    0
            );
            listview.setAdapter(sca); // attach the adapter to the listview
            // setup On Item Click to start the update activity passing the id
            listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                    Intent intent = new Intent(ListDataActivity.this,UpdateActivity.class);
                    intent.putExtra("my_id_extra",l);
                    startActivity(intent);
                }
            });
            // setup the on Item LONG Click to delete a row
            listview.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
                @Override
                public boolean onItemLongClick(AdapterView<?> adapterView, View view, int i, long l) {
                    databaseHelper.delete(l);
                    setOrRefreshListView(); // after deletion refresh the data
                    return true;
                }
            });
        } else {
            sca.swapCursor(cursor); // if not the first time just tell the adapter the data has changed
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        setOrRefreshListView(); // refresh the listview when returning to the activity
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        cursor.close(); // clean up
    }
}

The layout for ListDataActivity (very basic just a ListView) :-

<?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:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ListDataActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!" />

    <ListView
        android:id="@+id/mylistview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/teal_200"
        >
    </ListView>

</LinearLayout>

• background set so it's easy to see the ListView.

UpdateActivity :-

public class UpdateActivity extends AppCompatActivity {

    DatabaseHelper databaseHelper;
    EditText editName, editPhone;
    Button saveButtonId,showButtonId;
    long currentId;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_update);
        editName = this.findViewById(R.id.editName);
        editPhone = this.findViewById(R.id.editPhone);
        saveButtonId = this.findViewById(R.id.savebuttonId);
        showButtonId = this.findViewById(R.id.showbuttonId);
        databaseHelper = new DatabaseHelper(this);
        currentId =  this.getIntent().getLongExtra("my_id_extra",-1);
        if (currentId < 0 ) {
            // do something as invalid id passed
            finish();
        }
        showData();
        showButtonId.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                finish();
            }
        });
        saveButtonId.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                databaseHelper.update(currentId,editName.getText().toString(),null,editPhone.getText().toString());
            }
        });
    }

    private void showData() {
        Cursor cursor = databaseHelper.getById(currentId);
        if (cursor.moveToFirst()) {
            editName.setText(cursor.getString(cursor.getColumnIndex("name")));
            editPhone.setText(cursor.getString(cursor.getColumnIndex("phone")));
        }
        cursor.close();
    }
}

• showData button returns to ListDataActivity (I believe that's what you wanted).

Result :-

1. When started anew :-

2. Click on Mary (and edit number to 999999999 but not save) :-

3. Click Save (same as 2)

4. Click Show :-

5. Long Click Fred :-

6. Restart the App :-