Error when placing list on Android

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I’m starting now with the development for Android. I tried to put together a list but it’s not working. Preview only appears Item 1, Subitem 1.

Follow the . Java

public class Lista extends AppCompatActivity {


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.content_lista);


    String[] alunos = {"Ygor", "Carlos", "Paulo", "Joao", "Pedro"}; //Defini o vetor com os nomes
    ListView lista_alunos = (ListView) findViewById(R.id.lista); //(ListView) serve para converter a referência para ListView
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, alunos); //Transformar o Array para View
    lista_alunos.setAdapter(adapter); //Aqui a lista vai pedir para o adapter realizar a conversão para View
    }
}

and . xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<ListView
    android:id="@+id/lista"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

Could anyone see what’s wrong with this code? I couldn’t figure out where the bug is.

java android xml

  • What’s your question? This should work yes showing all items in list format. From what I see there is no subitem.

  • In my Androidstudio "Preview", only "Item 1, Sub Item1, Item2, Sub Item2" appears, my question is why the String is not appearing?

  • The preview will never show up anyway. You need to compile your project to make it work.

  • Before were appearing the names when I put all the names in "Textview", I will test here.

  • In text view it does appear, but everything you put inside your class will only appear if you compile.

  • I went on Android simulator and is appearing "process system isn’t responding". You know what can be?

  • I don’t know. You could edit your question and instead of putting "simulator" put what is in "Preview" your test.

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1 answer

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In the Preview from Android Studio, you can only see what is set in XML. So you can see what is set in your class Lista, in which a list is generated using ListView, it is necessary to compile the project and execute it on a virtual machine (AVD) or even on itself smartphone.

I tested your code and it is working perfectly, listing all the items declared in the variable alunos.

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