如何在 Android 中获取可用 Wi-Fi 网络并在列表中显示它们

此示例演示如何在 Android 中获取可用 Wi-Fi 网络并在列表中显示它们。

步骤 1 - 在 Android Studio 中创建一个新项目，转到文件 ⇒ 新建项目，并填写所有必需的详细信息以创建新项目。

步骤 2 - 将以下代码添加到 res/layout/activity_main.xml。

<?xml version = "1.0" encoding = "utf-8"?>
<RelativeLayout 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:layout_margin = "16dp"
   android:orientation = "vertical"
   tools:context = ".MainActivity">
   <ListView
      android:id = "@+id/wifiList"
      android:layout_width = "match_parent"
      android:layout_height = "match_parent"
      android:layout_above = "@+id/scanBtn" />
   <Button
      android:id = "@+id/scanBtn"
      android:layout_width = "match_parent"
      android:layout_height = "50dp"
      android:layout_alignParentBottom = "true"
      android:layout_gravity = "bottom"
      android:layout_margin = "15dp"
      android:text = "Scan WiFi" />
</RelativeLayout>

步骤 3 - 将以下代码添加到 src/MainActivity.java。

package com.example.myapplication;

import android.Manifest;
import android.content.Context;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.net.wifi.WifiManager;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
   private ListView wifiList;
   private WifiManager wifiManager;
   private final int MY_PERMISSIONS_ACCESS_COARSE_LOCATION = 1;
   WifiReceiver receiverWifi;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      wifiList = findViewById(R.id.wifiList);
      Button buttonScan = findViewById(R.id.scanBtn);
      wifiManager = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
      if (!wifiManager.isWifiEnabled()) {
         Toast.makeText(getApplicationContext(), "Turning WiFi ON...", Toast.LENGTH_LONG).show();
         wifiManager.setWifiEnabled(true);
      }
      buttonScan.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            if (ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.ACCESS_COARSE_LOCATION)
               ! = PackageManager.PERMISSION_GRANTED) {
               ActivityCompat.requestPermissions(
               MainActivity.this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, MY_PERMISSIONS_ACCESS_COARSE_LOCATION);
            } else {
               wifiManager.startScan();
            }
         }
      });
   }
   @Override
   protected void onPostResume() {
      super.onPostResume();
      receiverWifi = new WifiReceiver(wifiManager, wifiList);
      IntentFilter intentFilter = new IntentFilter();
      intentFilter.addAction(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
      registerReceiver(receiverWifi, intentFilter);
      getWifi();
   }
   private void getWifi() {
      if (Build.VERSION.SDK_INT > = Build.VERSION_CODES.M) {
         Toast.makeText(MainActivity.this, "version> = marshmallow", Toast.LENGTH_SHORT).show();
         if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.ACCESS_COARSE_LOCATION)
            ! = PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(MainActivity.this, "location turned off", Toast.LENGTH_SHORT).show();
            ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION},
               MY_PERMISSIONS_ACCESS_COARSE_LOCATION);
         } else {
            Toast.makeText(MainActivity.this, "location turned on", Toast.LENGTH_SHORT).show();
            wifiManager.startScan();
         }
      } else {
         Toast.makeText(MainActivity.this, "scanning", Toast.LENGTH_SHORT).show();
         wifiManager.startScan();
      }
   }
   @Override
   protected void onPause() {
      super.onPause();
      unregisterReceiver(receiverWifi);
   }
   @Override
   public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
      super.onRequestPermissionsResult(requestCode, permissions, grantResults);
      switch (requestCode) {
         case MY_PERMISSIONS_ACCESS_COARSE_LOCATION:
         if (grantResults.length > 0 && grantResults[0] = = PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(MainActivity.this, "permission granted", Toast.LENGTH_SHORT).show();
            wifiManager.startScan();
         } else {
            Toast.makeText(MainActivity.this, "permission not granted", Toast.LENGTH_SHORT).show();
            return;
         }
         break;
      }
   }
}

步骤 4 - 将以下代码添加到 src/WifiReceiver。

package com.example.myapplication;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;

class WifiReceiver extends BroadcastReceiver {
   WifiManager wifiManager;
   StringBuilder sb;
   ListView wifiDeviceList;
   public WifiReceiver(WifiManager wifiManager, ListView wifiDeviceList) {
      this.wifiManager = wifiManager;
      this.wifiDeviceList = wifiDeviceList;
   }
   public void onReceive(Context context, Intent intent) {
      String action = intent.getAction();
      if (WifiManager.SCAN_RESULTS_AVAILABLE_ACTION.equals(action)) {
         sb = new StringBuilder();
         List<ScanResult> wifiList = wifiManager.getScanResults();
         ArrayList<String> deviceList = new ArrayList<>();
         for (ScanResult scanResult : wifiList) {
            sb.append("
").append(scanResult.SSID).append(" - ").append(scanResult.capabilities);
            deviceList.add(scanResult.SSID + " - " + scanResult.capabilities);
         }
         Toast.makeText(context, sb, Toast.LENGTH_SHORT).show();
         ArrayAdapter arrayAdapter = new ArrayAdapter(context, android.R.layout.simple_list_item_1, deviceList.toArray());
         wifiDeviceList.setAdapter(arrayAdapter);
      }
   }
}

步骤 5 - 将以下代码添加到 androidManifest.xml。

<?xml version = "1.0" encoding = "utf-8"?>
<manifest xmlns:android = "http://schemas.android.com/apk/res/android"
   package = "com.example.myapplication">
   <uses-permission android:name = "android.permission.ACCESS_COARSE_LOCATION" />
   <uses-permission android:name = "android.permission.ACCESS_WIFI_STATE" />
   <uses-permission android:name = "android.permission.CHANGE_WIFI_STATE" />
   <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 = "com.example.myapplication.MainActivity">
         <intent-filter>
            <action android:name = "android.intent.action.MAIN" />
            <category android:name = "android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>

让我们尝试运行您的应用程序。我假设您已将您的实际 Android 移动设备连接到您的计算机。要从 Android Studio 运行应用程序，请打开您的一个项目活动文件，然后单击运行工具栏中的图标。选择您的移动设备作为选项，然后检查您的移动设备，它将显示您的默认屏幕 -