持续获取 Wifi RSSI 值 Android 应用程序无法启动

Question

我写了一个Android应用程序来获取wifi rssi值，而无需连接到wifi网络。

这是代码

package com.affno.wifirssichecker;
import android.content.Context;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;
import static com.affno.wifirssichecker.R.id.RSSI;
public class MainActivity extends AppCompatActivity {
TextView rssiView;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    rssiView = (TextView)findViewById(RSSI);
    WifiManager wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
    ScanResult result0 = (ScanResult) wifi.getScanResults();
    String ssid = result0.SSID;
    int rssi = result0.level;
    String rssiString0 = String.valueOf(rssi);
    rssiView.setText("n" + ssid + "   " + rssiString0);
}
}

但是当我将此应用程序部署到我的安卓设备中时，该应用程序将无法启动。 只是弹出然后消失。我不知道是什么问题。谁能帮我。

但我注意到在我测试此应用程序的区域有几个 wifi 网络。问题是否因此而出现？

我想要的是检查每个 Wifi 网络的 RSSI 值，并在我所在的区域周围持续使用 SSID 或 MAC

。我

想知道我能不能做到？

Answer 1

找不到确切的解决方案。但是我弄清楚问题出在哪里。我使用了在安卓版本6.0上运行的安卓设备。 因此，从Android 6.0开始，权限行为已更改为运行时。

所以在这种情况下，我需要扫描 Wifi 网络的权限。所以我需要检查之前是否授予了权限。如果是，我们可以运行应用程序，否则应用程序将崩溃。但是找不到解决此问题的正确方法。

Answer 2

我认为您需要获得 wifi 和位置 permissions.in Android 棉花糖及以上，您需要在运行时获得此权限。

这是我的代码！！维护.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.wifi">
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<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: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>
</application>
</manifest>`

主要活动.java

package com.example.wifi;
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.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.provider.Settings;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private WifiManager mwifiManager;
private List<ScanResult> results;
private ArrayList<String> arrayList = new ArrayList<>();
private ArrayAdapter<String> adapter;
private int REQUEST_PERMISSION_CODE = 1;
private String[] Permissions = {Manifest.permission.ACCESS_COARSE_LOCATION,
                                Manifest.permission.ACCESS_FINE_LOCATION,
                                Manifest.permission.ACCESS_WIFI_STATE,
                                Manifest.permission.CHANGE_WIFI_STATE};
boolean start ;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Button scan_btn = (Button) findViewById(R.id.button);
    ListView list = (ListView) findViewById(R.id.list);

    scan_btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            scan_wifi();
        }
    });
}
@Override
protected void onStart() {
    super.onStart();
    requestPermissions();
}
@Override
protected void onResume() {
    super.onResume();
    scan_wifi();
}
private void scan_wifi(){
    if(start){
        mwifiManager = (WifiManager) 
getApplicationContext().getSystemService(Context.WIFI_SERVICE);
        if (!mwifiManager.isWifiEnabled()) {
            Toast.makeText(this, "WIFI DISABLED", Toast.LENGTH_LONG).show();
            mwifiManager.setWifiEnabled(true);
        }
        registerReceiver(wifireceiver,new 
IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
        mwifiManager.startScan();
        Toast.makeText(this,"SCANING",Toast.LENGTH_LONG).show();
    }
    else {
        /* GET RUN TIME PERMISSION*/
        requestPermissions();
    }
}
private void requestPermissions() {
    if (    (ContextCompat.checkSelfPermission(this, Permissions[0]) != 
PackageManager.PERMISSION_GRANTED)||
            (ContextCompat.checkSelfPermission(this, Permissions[1]) != 
PackageManager.PERMISSION_GRANTED)||
            (ContextCompat.checkSelfPermission(this, Permissions[2]) != 
PackageManager.PERMISSION_GRANTED)||
            (ContextCompat.checkSelfPermission(this, Permissions[3]) != 
PackageManager.PERMISSION_GRANTED)) {
        ActivityCompat.requestPermissions(this, new String[]{Permissions[0],
                                                                    Permissions[1],
                                                                    Permissions[2],
                                                                    Permissions[3]},
                                            REQUEST_PERMISSION_CODE);
    } else {
        //Toast.makeText(this, "Permission alredy granted", 
Toast.LENGTH_SHORT).show();
        start = true;
    }
}
BroadcastReceiver wifireceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        TextView tx = (TextView) findViewById(R.id.textView);
        tx.setText("WIFI LIST n");
        results = mwifiManager.getScanResults();
        unregisterReceiver(this);
        results = mwifiManager.getScanResults();
        Log.d("Wifi", String.valueOf(results.size()));
        for (ScanResult res : results) {
            tx.append("SSID :" +res.SSID + "Capblt :" + res.capabilities+ "n");
        }
    }
};

@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] 
grantResults) {
    if(requestCode == REQUEST_PERMISSION_CODE){
        if (grantResults.length > 0 && grantResults[0] == 
PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(this, "Permission granted", Toast.LENGTH_SHORT).show();
            start = true;
        }
        else {
            Toast.makeText(this, "Permission not granted", 
Toast.LENGTH_SHORT).show();
            start = false;
        }
    }
    }


}