Android活動刷新（SwipeRefreshLayout）

在本教程中，我們將在Android中創建下拉刷新的功能。愛掏網 - it200.com為此，應使用SwipeRefreshLayout小部件。愛掏網 - it200.com

SwipeRefreshLayout的實例添加了OnRefreshListener方法，并實現了在刷新時加載的代碼邏輯。愛掏網 - it200.com當用戶滑動時，垂直滑動會顯示一個獨特的進度條。愛掏網 - it200.com進度條在顯示進度動畫時調用setRefreshing(true)，或者調用setRefreshing(false)來取消。愛掏網 - it200.com

在activity_main.xml文件中實現SwipeRefreshLayout小部件。愛掏網 - it200.com

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.SwipeRefreshLayout 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:id="@+id/refreshLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="example.javatpoint.com.swiperefreshlayout.MainActivity">

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="229dp"
            android:text="Hello World!"
            android:textSize="18dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    </RelativeLayout>
</android.support.v4.widget.SwipeRefreshLayout>

創建一個活動 MainActivity.java 并添加以下代碼。愛掏網 - it200.com在這個類中，我們在刷新時檢查網絡連接。愛掏網 - it200.com

MainActivity.java

package example.javatpoint.com.swiperefreshlayout;

import android.content.Context;
import android.graphics.Color;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    SwipeRefreshLayout swipeRefreshLayout;
    TextView textView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        swipeRefreshLayout = findViewById(R.id.refreshLayout);
        textView = findViewById(R.id.textView);
        swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                       swipeRefreshLayout.setRefreshing(false);
                       //your code on swipe refresh
                       //we are checking networking connectivity
                        boolean connection=isNetworkAvailable();
                        if(connection){
                            textView.setText("internet connect");
                            textView.setTextColor(Color.GREEN);
                        }
                        else{
                            textView.setText("not connected");
                            textView.setTextColor(Color.RED);
                        }

            }
        });
        swipeRefreshLayout.setColorSchemeColors(Color.YELLOW);
    }
    public boolean isNetworkAvailable(){

        ConnectivityManager connectivityManager=(ConnectivityManager) this.getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo=connectivityManager.getActiveNetworkInfo();
        return networkInfo !=null;
    }
}

所需權限

將以下權限添加到 AndroidMenifest.xml 文件中。愛掏網 - it200.com下面給出的權限用于訪問網絡連接。愛掏網 - it200.com

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>