Java

Building the interface

To be able to place the call, you need to add three elements to the screen:

A TextView to show the connection status
A Button to start the call
A Button to end the call

Open the app/res/layout/activity_main.xml file. Click the Code button in the top right corner:

Replace the file contents with the following:

You will control the view using code, so you have to store references to the views. Add these properties at the top of the MainActivity class:

private ConstraintLayout chatContainer;
private LinearLayout loginContainer;
private EditText messageEditText;
private TextView conversationTextView;

Now you need to assign views to previously added properties. Add below code to the onCreate method inside MainActivity class (below request permissions code):

chatContainer = findViewById(R.id.chatContainer);
loginContainer = findViewById(R.id.loginContainer);
messageEditText = findViewById(R.id.messageEditText);
conversationTextView = findViewById(R.id.conversationTextView);

Now you need to assign views to previously added properties. Add below code to the onCreate method inside MainActivity class (below request permissions code):

chatContainer = findViewById(R.id.chatContainer);
loginContainer = findViewById(R.id.loginContainer);
messageEditText = findViewById(R.id.messageEditText);
conversationTextView = findViewById(R.id.conversationTextView);