如何将数据放入XML的ListView中？

Question

I just started learning Android and I am trying to create a simple view where a portion of the main XML is a listview.

Here is my main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


    <RelativeLayout
        android:layout_width="100dp"
        android:layout_height="match_parent"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"
        android:id="@+id/Menu">

        <ImageButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/menu_item_1"
            android:layout_alignParentTop="true"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="129dp" />

    </RelativeLayout>

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:layout_toEndOf="@+id/Menu"
        android:layout_toRightOf="@+id/Menu"
        android:layout_alignParentTop="true"
        android:id="@+id/Banner">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:text="Account Log"
            android:layout_gravity="center"
            android:inputType="none"
            android:textStyle="bold"/>
    </FrameLayout>

    <ListView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/Log"
        android:layout_toRightOf="@+id/Menu"
        android:layout_below="@+id/Banner"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:choiceMode="none"
        android:clickable="false"
        android:contextClickable="true"
        android:fadeScrollbars="true" />

</RelativeLayout>

Assuming that I have a function called getDatafromFile() which returns an ArrayList of data, how do I put those data into my listView?

I've heard of using ArrayAdapter but the examples I've seen puts ListView to the entire layout.

Answer 1

Full code of create list view

public class MainActivity extends AppCompatActivity {

ArrayList<String>arrayList=new ArrayList<>();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main); //here is the layout where your views exists

    for (int i=0;i<=20;i++){
        arrayList.add("List Items"+i);   //assume we passed the data in arraylist
    }
    ListView listView=(ListView)findViewById(R.id.log); //your listview

    ArrayAdapter arrayAdapter=new ArrayAdapter(this,android.R.layout.simple_list_item_1,arrayList);//the second argument is a layout file that have a textview

    listView.setAdapter(arrayAdapter);



}
}

Answer 2

The best way to put data in your ListView is by making an ArrayAdapter Class. I always recommend you to try using a custom adapter class so that you can change it as per your requirement. You can create a class that extends ArrayAdapter. Then pass the arraylist that you want inside your list view to that adapter constructor. For Example, below is a custom adapter class

public class CustomAdapter extends ArrayAdapter<DataInfo> {


ArrayList<DataInfo> itemList =new ArrayList<>();
Context context;
LayoutInflater inflater;
public CustomAdapte(Context context, ArrayList<VegInfo> list) {
    super(context, R.layout.list_item, list);
    this.context = context;
    itemList = list;
    inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {

    //getting an item from the list
    DataInfo item = itemList.get(position);
    if(convertView==null)
        convertView = inflater.inflate(R.layout.list_item,parent,false);

        //displaying some data from your data info in a textview
    TextView textView = (TextView) convertView.findViewById(R.id.tv);
    textView.setText(item.subitem);


    return convertView;
}
}

Inside your Activity, You can set the data to that adapter.

 CustomAdapter yourAdapter = new CustomAdapte(activity,yourArrayList);
 yourListView.setAdapter(yourAdapter);

Now, your list view have the data inside the array list. Whenever there is a change in the array list, it can be reflected in the list view just by calling

yourAdapter.notifydatasetchanged();

Here list_item is a custom XML file that you should create for a single list item view.

Hope this helps you. If not please tell me and let me make it more clear. happy coding.