Swipe-to-Refresh ListView using SwipeRefreshLayout

With android.support.v4.widget.SwipeRefreshLayout, user can refresh the contents of a view via a vertical swipe gesture. This example show how to implement Swipe-to-Refresh ListView using SwipeRefreshLayout.


activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androidswiperefresh.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />

    <android.support.v4.widget.SwipeRefreshLayout
        android:id="@+id/swiperefreshlayout"
        android:layout_height="match_parent"
        android:layout_width="match_parent">
        <ListView
            android:id="@+id/swipelist"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>
    </android.support.v4.widget.SwipeRefreshLayout>

</LinearLayout>

MainActivity.java

package com.blogspot.android_er.androidswiperefresh;

import android.os.Bundle;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;

import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    SwipeRefreshLayout swipeRefreshLayout;
    ListView swipeList;

    List<String> myList;
    ListAdapter adapter;

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

        swipeRefreshLayout = (SwipeRefreshLayout)findViewById(R.id.swiperefreshlayout);
        swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                refresh();
            }
        });

        swipeList = (ListView)findViewById(R.id.swipelist);

        myList = new ArrayList<>();
        adapter = new ArrayAdapter<String>(
                this, android.R.layout.simple_list_item_1, myList);
        swipeList.setAdapter(adapter);
    }

    private void refresh(){
        //insert dummy string of current date/time
        String currentDateTime = DateFormat.getDateTimeInstance().format(new Date());
        myList.add(currentDateTime);
        swipeList.invalidateViews();
        swipeRefreshLayout.setRefreshing(false);
    }
}

In this example, the ListView items is updated in SwipeRefreshLayout.OnRefreshListener(). But normally refreshing involve longtime task, such as loading from Internet. The next example show how to refresh with longtime task run in background thread.