Working with Navigation Bar (smartphone native) and Action Bar BACK buttons (added via Java)

Question

I am Asking this question/answer to help those who may have/have/have some doubt regarding the buttons BACK that are extremely useful in our applications. I will use 1 and 2 to differentiate Action Bar (1) and Navigation Bar (2)

Thank you very much to the users here of Stack who helped me to find this solution that were: Jean Felipe D. Silva and Regmoraes

Answer 1

1. Back - Action Bar

• Within the method onCreate(){ add the following lines:

  getSupportActionBar().setDisplayHomeAsUpEnabled(true); //Mostrar o botão
  getSupportActionBar().setHomeButtonEnabled(true);      //Ativar o botão
  getSupportActionBar().setTitle("Seu titulo aqui");     //Titulo para ser exibido na sua Action Bar em frente à seta
  

• Out of method oncreate(){} add:

  @Override
  public boolean onOptionsItemSelected(MenuItem item) { //Botão adicional na ToolBar
  switch (item.getItemId()) {
      case android.R.id.home:  //ID do seu botão (gerado automaticamente pelo android, usando como está, deve funcionar
          startActivity(new Intent(this, SuaActivity.class));  //O efeito ao ser pressionado do botão (no caso abre a activity)
          finishAffinity();  //Método para matar a activity e não deixa-lá indexada na pilhagem
          break;
      default:break;
  }
  return true;
  }
  

All set, you button Action Bar is working!

2. Back - Navigation Bar

• Out of method onCreate(){}

  @Override
  public void onBackPressed(){ //Botão BACK padrão do android
  startActivity(new Intent(this, MainActivity.class)); //O efeito ao ser pressionado do botão (no caso abre a activity)
  finishAffinity(); //Método para matar a activity e não deixa-lá indexada na pilhagem
  return;
  }
  

Everything should be working perfectly now

Answer 2

You can resolve this in the manifest by adding this attribute to the current Activity

android:parentActivityName=".activity.PrincipalActivity"

Answer 3

Complementing the response of Erasmus and adding the attribute parentActivityName, also add the attribute launchMode in the block that is intended for the main screen. I will put a code below better describing my answer.

Where the manisfest of its application:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.exemplo.ExemploDeCodigo">


    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat.Light.NoActionBar">

        <activity
            android:name=".SegundaActivity"
            android:parentActivityName=".MainActivity" >
        </activity>

        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

Each time a new Activity is added to your project, you add the parentActivityName pointing to the Activity that you wish to return.

Another interesting point is that if you don’t want to lose any data from a screen and you want it to stay the same by moving to the next screen and then returning, just use the android:launchMode="singleTop", this will cause the data to be kept.