AutoComplete TextView

//Java Code
public class MainActivity extends AppCompatActivity {

AutoCompleteTextView autoCompleteTextView;
TextView textView;
String details[] = {"Personal Details","Work Details","Graduation Details","Private Details"};
ArrayAdapter<String> adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        autoCompleteTextView = findViewById(R.id.ac_text_view);
        textView = findViewById(R.id.textView2);
        
    adapter = new ArrayAdapter(this,android.R.layout.simple_dropdown_item_1line,details);
    
    //get  suggestion after the number of word types
        autoCompleteTextView.setThreshold(1);
        //set adapter
        autoCompleteTextView.setAdapter(adapter);
        autoCompleteTextView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                textView.setText(adapter.getItem(i));
            }
        });

    }
}
//XML Layout
<AutoCompleteTextView
        android:id="@+id/ac_text_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@android:drawable/editbox_background"
        android:hint="Search..."
        android:padding="12dp"/>
        
        <TextView
        android:id="@+id/textView2"
        android:layout_width="254dp"
        android:layout_height="41dp"
        android:layout_marginTop="112dp"
        android:text="Personal Info."
        android:textSize="25sp"/>