写一个Android wifi开发程序，适配android11，包括wifi打开、关闭、扫描、连接、断开

以下是一份简单的Android wifi开发程序，适配android 11，包括wifi打开、关闭、扫描、连接和断开。

Java代码：

import android.Manifest;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.wifi.WifiConfiguration;
import android.net.wifi.WifiInfo;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.util.Log;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

@RequiresApi(30)
public class MainActivity extends AppCompatActivity {

    private final int REQUEST_CODE_LOCATION_PERMISSION = 100;
    private final int REQUEST_CODE_WIFI_PERMISSION = 101;

    private WifiManager wifiManager;
    private boolean isWifiEnabled;
    private WifiScanReceiver wifiScanReceiver;
    private List<WifiConfiguration> wifiConfigurations;
    private List<WifiInfo> wifiInfos;
    private List<ScanResult> scanResults;
    private boolean isConnected;
    private Handler handler;

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

        wifiManager = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
        isWifiEnabled = wifiManager.isWifiEnabled();
        wifiScanReceiver = new WifiScanReceiver();
        wifiConfigurations = wifiManager.getConfiguredNetworks();
        wifiInfos = new ArrayList<>();
        scanResults = new ArrayList<>();
        isConnected = false;
        handler = new Handler(Looper.getMainLooper());

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_CODE_LOCATION_PERMISSION);
        } else {
            enableWifi();
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        IntentFilter intentFilter = new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
        registerReceiver(wifiScanReceiver, intentFilter);
    }

    @Override
    protected void onPause() {
        super.onPause();
        unregisterReceiver(wifiScanReceiver);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        disconnect();
        disableWifi();
    }

    private void enableWifi() {
        if (!isWifiEnabled) {
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.CHANGE_WIFI_STATE) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CHANGE_WIFI_STATE}, REQUEST_CODE_WIFI_PERMISSION);
            } else {
                wifiManager.setWifiEnabled(true);
                isWifiEnabled = true;
                Toast.makeText(this, "开启Wifi", Toast.LENGTH_SHORT).show();
            }
        }
    }

    private void disableWifi() {
        if (isWifiEnabled) {
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.CHANGE_WIFI_STATE) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CHANGE_WIFI_STATE}, REQUEST_CODE_WIFI_PERMISSION);
            } else {
                wifiManager.setWifiEnabled(false);
                isWifiEnabled = false;
                Toast.makeText(this, "关闭Wifi", Toast.LENGTH_SHORT).show();
            }
        }
    }

    private void scanWifi() {
        if (isWifiEnabled) {
            wifiManager.startScan();
            Toast.makeText(this, "开始扫描Wifi", Toast.LENGTH_SHORT).show();
        }
    }

    private void connect(WifiConfiguration wifiConfiguration) {
        if (isWifiEnabled) {
            int networkId = wifiManager.addNetwork(wifiConfiguration);
            if (networkId != -1) {
                wifiManager.saveConfiguration();
                wifiManager.disconnect();
                wifiManager.enableNetwork(networkId, true);
                wifiManager.reconnect();
                isConnected = true;
                Toast.makeText(this, "已连接Wifi", Toast.LENGTH_SHORT).show();
            } else {
                isConnected = false;
                Toast.makeText(this, "连接Wifi失败", Toast.LENGTH_SHORT).show();
            }
        }
    }

    private void disconnect() {
        if (isWifiEnabled && isConnected) {
            wifiManager.disconnect();
            isConnected = false;
            Toast.makeText(this, "已断开Wifi连接", Toast.LENGTH_SHORT).show();
        }
    }

    private void requestLocationPermission() {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_CODE_LOCATION_PERMISSION);
    }

    private void requestWifiPermission() {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CHANGE_WIFI_STATE}, REQUEST_CODE_WIFI_PERMISSION);
    }

    // 单独提取出请求权限的onRequestPermissionsResult方法，后续修改方便
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (requestCode == REQUEST_CODE_LOCATION_PERMISSION) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                enableWifi();
            } else {
                Toast.makeText(this, "请求位置权限失败，无法开启Wifi", Toast.LENGTH_SHORT).show();
            }
        }
        if (requestCode == REQUEST_CODE_WIFI_PERMISSION) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                if (isWifiEnabled) {
                    disableWifi();
                } else {
                    enableWifi();
                }
            } else {
                Toast.makeText(this, "请求Wifi权限失败", Toast.LENGTH_SHORT).show();
            }
        }
    }

    // Broadcast Receiver
    private class WifiScanReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            if (intent.getAction().equals(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)) {
                scanResults = wifiManager.getScanResults();
                sortScanResultsByLevel();
                Toast.makeText(context, "扫描结束，共找到" + scanResults.size() + "个Wifi", Toast.LENGTH_SHORT).show();
            }
        }
    }

    // 排序
    private void sortScanResultsByLevel() {
        Collections.sort(scanResults, new Comparator<ScanResult>() {
            @Override
            public int compare(ScanResult o1, ScanResult o2) {
                return o2.level - o1.level;
            }
        });
    }

    // 获取连接状态
    private boolean getConnectivityStatus() {
        ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
        if (networkInfo != null && networkInfo.isConnectedOrConnecting()) {
            return true;
        } else {
            return false;
        }
    }
}