安卓简单的listview操作

LISTVIEW学习

最简单的字符串列表
MainActivity.java

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listView = findViewById(R.id.listView);

        String[] arr = new String[]{
                "1","2","3"
        };
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(
                MainActivity.this,android.R.layout.simple_list_item_1,arr
        );
        listView.setAdapter(adapter);

    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

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

</android.support.constraint.ConstraintLayout>