Customize Navigation View UI elements

Navigation View is the UI provided to show the navigation route process. In this example we will show how to do customization on Navigation View, including:

Add a new UI element by customizing the activity layout
Show or hide existing Navigation View UI elements

As is shown in the above image, we customized the Navigation View app bar and added a switch button to it. A user tapping the switch button will change the visibility of two UI elements (Recenter Button and Sound button), which are originally existing in Navigation View.

For all code examples, refer to Navigation Code Examples

activity_custom_element_visibility.xml view source

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<?xml version="1.0" encoding="utf-8"?>
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<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
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    xmlns:app="http://schemas.android.com/apk/res-auto"
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    xmlns:tools="http://schemas.android.com/tools"
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    android:layout_width="match_parent"
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    android:layout_height="match_parent"
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    tools:context=".activity.CustomElementVisibilityActivity">
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    <ai.nextbillion.navigation.ui.NavigationView
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        android:id="@+id/custom_element_navigation_view"
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        android:layout_width="match_parent"
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        android:layout_height="match_parent"/>
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</androidx.constraintlayout.widget.ConstraintLayout>

CustomElementVisibilityActivity view source

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package ai.nextbillion.navigation.demo.activity;
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import android.os.Bundle;
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import android.view.Menu;
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import android.view.MenuItem;
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import ai.nextbillion.kits.directions.models.DirectionsResponse;
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import ai.nextbillion.kits.directions.models.RouteRequestParams;
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import ai.nextbillion.navigation.core.routefetcher.RequestParamsWrapper;
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import ai.nextbillion.navigation.demo.R;
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import ai.nextbillion.navigation.ui.NavViewConfig;
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import ai.nextbillion.navigation.ui.NavigationView;
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import ai.nextbillion.navigation.ui.OnNavigationReadyCallback;
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import ai.nextbillion.navigation.ui.listeners.NavigationListener;
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import android.annotation.Nullable;
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import androidx.appcompat.app.AppCompatActivity;
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import androidx.appcompat.widget.SwitchCompat;
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import java.io.IOException;
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import java.io.InputStream;
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import java.util.Scanner;
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/***
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 * This class demonstrates how to add an extra switch button on Appbar
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 * and use the switch button to control the display of UI elements in Navigation view
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 */
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public class CustomElementVisibilityActivity extends AppCompatActivity implements OnNavigationReadyCallback, NavigationListener {
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    private NavigationView navigationView;
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    @Override
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    protected void onCreate(@Nullable Bundle savedInstanceState) {
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        super.onCreate(savedInstanceState);
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        setContentView(R.layout.activity_custom_element_visibility);
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        navigationView = findViewById(R.id.custom_element_navigation_view);
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        navigationView.onCreate(savedInstanceState);
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        navigationView.initialize(this);
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    }
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    @Override
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    public boolean onCreateOptionsMenu(Menu menu) {
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        // Inflate the menu; this adds items to the action bar if it is present.
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        getMenuInflater().inflate(R.menu.mainmenu, menu);
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        MenuItem item = menu.findItem(R.id.myswitch);
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        SwitchCompat mySwitch = (SwitchCompat) item.getActionView();
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        // adding this here to keep the initial display consistency of the UI elements
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        controlDisplayOfElements(mySwitch.isChecked());
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        // The on-click event will be triggered each time user clicks the switch button on the App bar
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        mySwitch.setOnCheckedChangeListener((buttonView, isChecked) -> {
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            controlDisplayOfElements(isChecked);
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        });
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        return true;
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    }
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    private void controlDisplayOfElements(boolean shouldDisplay) {
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        if (shouldDisplay) {
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            navigationView.showRecenterBtn();
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            navigationView.retrieveSoundButton().show();
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        } else {
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            navigationView.hideRecenterBtn();
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            navigationView.retrieveSoundButton().hide();
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        }
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    }
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    @Override
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    public void onNavigationReady(boolean b) {
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        // read original backend response from file
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        DirectionsResponse response = DirectionsResponse.fromJson(loadJsonFromAsset());
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        // modify the backend response following normal api call process
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        DirectionsResponse modifiedResponse = new RequestParamsWrapper().wrapRequestParams(response, RouteRequestParams.builder().build());
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        NavViewConfig.Builder config =
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                NavViewConfig.builder().route(modifiedResponse.routes().get(0))
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                        // The visibility of speedometer can be set here before starting navigation
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                        .showSpeedometer(true)
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                        // add this so the exit button in Navigation view would work
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                        .navigationListener(this)
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                        .shouldSimulateRoute(true);
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        navigationView.startNavigation(config.build());
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    }
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    private static String convertStreamToString(InputStream is) {
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        Scanner s = new Scanner(is).useDelimiter("\\A");
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        return s.hasNext() ? s.next() : "";
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    }
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    private String loadJsonFromAsset() {
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        // Using this method to load GeoJSON files from the assets folder.
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        try {
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            return convertStreamToString(getApplicationContext().getAssets().open("directions-route.json"));
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        } catch (IOException ex) {
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            ex.printStackTrace();
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            return null;
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        }
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    }
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    @Override
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    public void onStart() {
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        super.onStart();
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        navigationView.onStart();
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    }
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    @Override
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    public void onResume() {
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        super.onResume();
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        navigationView.onResume();
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    }
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    @Override
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    public void onLowMemory() {
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        super.onLowMemory();
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        navigationView.onLowMemory();
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    }
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    @Override
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    public void onBackPressed() {
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        // If the navigation view didn't need to do anything, call super
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        if (!navigationView.onBackPressed()) {
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            super.onBackPressed();
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        }
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    }
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    @Override
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    protected void onSaveInstanceState(Bundle outState) {
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        navigationView.onSaveInstanceState(outState);
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        super.onSaveInstanceState(outState);
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    }
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    @Override
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    protected void onRestoreInstanceState(Bundle savedInstanceState) {
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        super.onRestoreInstanceState(savedInstanceState);
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        navigationView.onRestoreInstanceState(savedInstanceState);
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    }
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    @Override
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    public void onPause() {
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        super.onPause();
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        navigationView.onPause();
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    }
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    @Override
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    public void onStop() {
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        super.onStop();
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        navigationView.onStop();
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    }
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    @Override
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    protected void onDestroy() {
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        super.onDestroy();
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        navigationView.onDestroy();
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    }
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    @Override
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    public void onCancelNavigation() {
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        finish();
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    }
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    @Override
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    public void onNavigationFinished() {
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    }
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    @Override
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    public void onNavigationRunning() {
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    }
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}

Code Highlights

The main logic of the code example is to use a switch button to control the visibility of the Recenter button and the Sound button in the navigation view.

The controlDisPlayOfElement() function shows how to display or hide the corresponding view during navigation.

Code summary

The code snippet is for an Android activity that allows users to control the visibility of elements in a navigation view. The activity extends the AppCompatActivity class and implements the OnNavigationReadyCallback and NavigationListener interfaces.

The activity's onCreate() method first inflates the activity_custom_element_visibility layout. It then finds the navigationView view in the layout and calls its onCreate() method. Finally, it calls the initialize() method on the navigationView to initialize it.

The activity's onCreateOptionsMenu() method inflates the mainmenu menu. It then finds the myswitch menu item and gets its SwitchCompat view. The activity then calls the controlDisplayOfElements() method to set the initial visibility of the elements in the navigation view. The activity also sets a listener on the myswitch view so that it can be updated when the user changes the switch's state.

The controlDisplayOfElements() method takes a boolean value as input. If the value is true, the method shows the Recenter button and the Sound button in the navigation view. If the value is false, the method hides the buttons.

The onNavigationReady() method is called when the navigation view is ready. The method reads the original backend response from a file. It then modifies the response and creates a NavViewConfig object. The NavViewConfig object specifies the route that will be navigated, whether the speedometer will be shown and whether the navigation listener will be used. The method then calls the startNavigation() method on the navigation view to start navigation.

The convertStreamToString() method converts an input stream to a string. The method uses a Scanner object to read the stream and a delimiter to determine where the stream ends.

The loadJsonFromAsset() method loads a GeoJSON file from the assets folder. The method tries to open the file and read its contents. If the file cannot be opened, the method returns null.

The activity uses the NavigationView class to display a navigation view in the user interface. The activity also uses the OnNavigationReadyCallback and NavigationListener interfaces to interact with the navigation view.