本文概述
Android网络连接服务使我们能够检查设备的网络连接信息。在执行基于Internet服务的任务（例如从服务器（互联网）获取数据或将数据写入服务器）的任务时，检查设备的Internet连接非常重要。
使用Android网络连接服务，我们还可以确定android设备网络的类型。它可能是TYPE_WIFI（wifi），TYPE_MOBILE（手机），TYPE_BLUETOOTH（蓝牙）等类型。
Android网络连接服务示例
让我们创建一个简单的示例来检查设备的网络连接及其类型。
要访问设备的网络连接，我们需要在AndroidMenifest.xml文件中提供网络访问权限。
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />在布局的activity_main.xml文件中，添加以下代码。对于访问设备的网络状态，不需要布局文件。在这里，我们仅使用activity_main.xml文件存储网络类型的状态。
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="example.srcmini02.com.networkconnectivityservice.MainActivity">
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="16dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:contentDescription="networkstate"
android:text="Network state ?"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.183" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:text="Check Connection Type"
android:layout_marginTop="392dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>创建一个名为NetworkState.java的Java类。此类包含getConnectivityStatus（）方法，该方法根据当前的网络连接返回常量整数值。
代码context.getSystemService（Context.CONNECTIVITY_SERVICE）用于返回访问网络属性的ConnectivityManager类的实例。
NetworkState.java
package example.srcmini02.com.networkconnectivityservice;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
public class NetworkState {
public static int TYPE_NOT_CONNECTED = 0;
public static int TYPE_WIFI = 1;
public static int TYPE_MOBILE = 2;
public static int getConnectivityStatus(Context context) {
ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
if (null != activeNetwork) {
if(activeNetwork.getType() == ConnectivityManager.TYPE_WIFI)
return TYPE_WIFI;
if(activeNetwork.getType() == ConnectivityManager.TYPE_MOBILE)
return TYPE_MOBILE;
}
return TYPE_NOT_CONNECTED;
}
public static String getConnectivityStatusString(Context context) {
int conn = NetworkState.getConnectivityStatus(context);
String status = null;
if (conn == NetworkState.TYPE_WIFI) {
status = "Wifi enabled";
} else if (conn == NetworkState.TYPE_MOBILE) {
status = "Mobile data enabled";
} else if (conn == NetworkState.TYPE_NOT_CONNECTED) {
status = "Not connected to Internet";
}
return status;
}
}创建一个名为NetworkReceiver.java的接收器类，并扩展BroadcastReciever类。此类处理设备的网络状态中发生的更改。设备的网络状态更改时，将调用BroadcastReciever类的onReceive（）方法。
NetworkReceiver.java
package example.srcmini02.com.networkconnectivityservice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;
public class NetworkReceiver extends BroadcastReceiver {
static String status =null;
@Override
public void onReceive(Context context, Intent intent) {
status = NetworkState.getConnectivityStatusString(context);
Toast.makeText(context, status, Toast.LENGTH_LONG).show();
if(status == "Wifi enabled"){
//your code when wifi enable
}
else if(status=="Mobile data enabled"){
//your code when TYPE_MOBILE network enable
}
else if(status=="Not connected to Internet"){
//your code when no network connected
}
}
}在MainActivity.java类中，我们通过单击Button在TextView中显示设备的网络状态。
MainActivity.java
package example.srcmini02.com.networkconnectivityservice;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
Button button;
TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = findViewById(R.id.button);
textView = findViewById(R.id.textView);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
NetworkReceiver receiver = new NetworkReceiver() ;
String networkStatus = receiver.status;
textView.setText("connection type: "+networkStatus);
Toast.makeText(getApplicationContext(), networkStatus, Toast.LENGTH_LONG).show();
}
});
}
}在AndroidMenifest.xml文件中，添加网络访问权限和用于处理BroadcastReceiver类中发生的更改的接收器类。
AndroidMenifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="example.srcmini02.com.networkconnectivityservice">
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver
android:name=".NetworkReceiver"
android:enabled="true">
<intent-filter>
<action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
<action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
</intent-filter>
</receiver>
</application>
</manifest>输出量
