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public class MainActivity extends AppCompatActivity {

    ListView listView;
    ArrayList<String> listItem = new ArrayList<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }
    public void onAdd(View v)
    {
        EditText e=findViewById(R.id.editText);
        listItem.add(e.getText().toString());
        listView = findViewById(R.id.l1);
        final ArrayAdapter<String> adapter = new ArrayAdapter<>(this,
                android.R.layout.simple_list_item_1, listItem);
        listView.setAdapter(adapter);

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
                // TODO Auto-generated method stub
                String value=adapter.getItem(position);
                Toast.makeText(getApplicationContext(),value,Toast.LENGTH_SHORT).show();

            }
        });
    }
}

<ListView
        android:id="@+id/l1"
        android:layout_width="404dp"
        android:layout_height="588dp"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:layout_marginTop="8dp"
        android:layout_marginBottom="8dp"
        app:layout_constraintBottom_toTopOf="@+id/editText"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

    </ListView>

    <EditText
        android:hint="@string/hint"
        android:id="@+id/editText"
        android:inputType="text"
        android:layout_width="205dp"
        android:layout_height="42dp"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginBottom="8dp"
        app:layout_constraintBottom_toBottomOf="@+id/button"
        app:layout_constraintEnd_toStartOf="@+id/button"
        app:layout_constraintStart_toStartOf="parent" />

    <Button
        android:text="@string/buttonHint"
        android:id="@+id/button"
        android:onClick="onAdd"
        android:layout_width="109dp"
        android:layout_height="35dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:layout_marginBottom="32dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />