弹出窗口无法获得wifi扫描结果

Question

我试图在弹出窗口中获取wifi扫描结果，但它强制关闭。如果有任何我寻找同样的问题可能提供我的代码，但无法找到结果。 Wifi转身，扫描的烤面包出现后不久就停止了错误 这是我的代码

MainActivity.java

    package com.example.hemang.wifi_app;

    import android.content.Intent;
    import android.net.wifi.WifiManager;
    import android.support.v4.view.GestureDetectorCompat;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.GestureDetector;
    import android.view.MotionEvent;

   public class MainActivity extends AppCompatActivity implements     GestureDetector.OnGestureListener {


GestureDetectorCompat gd;


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

    this.gd = new GestureDetectorCompat(MainActivity.this,MainActivity.this);
}

@Override
public boolean onDown(MotionEvent e) {
    Intent i = new Intent(MainActivity.this,popup.class);
    startActivity(i);
    return true;
}

@Override
public void onShowPress(MotionEvent e) {

}

@Override
public boolean onSingleTapUp(MotionEvent e) {
    return false;
}

@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
    return false;
}

@Override
public void onLongPress(MotionEvent e) {

}

@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
    return false;
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    this.gd.onTouchEvent(event);
    return super.onTouchEvent(event);
}

}

Popup.java

    package com.example.hemang.wifi_app;

    import android.app.Activity;
    import android.content.BroadcastReceiver;
    import android.content.Context;
    import android.content.Intent;
    import android.content.IntentFilter;
    import android.graphics.Color;
    import android.net.wifi.ScanResult;
    import android.net.wifi.WifiManager;
    import android.os.Bundle;
    import android.util.DisplayMetrics;
    import android.view.View;
    import android.widget.ArrayAdapter;
    import android.widget.Button;
    import android.widget.ListView;
    import android.widget.RadioButton;
    import android.widget.Toast;

    import java.util.List;

    public class popup extends Activity {


WifiManager wifiManager;
WifiReceiver wifiReceiver;
 RadioButton b1;
Button b2;
ListView lv;



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

    DisplayMetrics displayMetrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);

    int width = displayMetrics.widthPixels;
    int height = displayMetrics.heightPixels;

    getWindow().setLayout((int) (width * 0.8), (int) (height * 0.5));



    final RadioButton b1 = (RadioButton)findViewById(R.id.radioButton);
    Button b2 =(Button)findViewById(R.id.scanbutton);

    b1.setOnClickListener(new Button.OnClickListener() {

        int counter = 0;
        public void onClick(View v) {
            if(counter==0){
                b1.setChecked(true);
                b1.setTextColor(Color.WHITE);
               // Toast.makeText(popup.this,"Turning Wifi ON",Toast.LENGTH_SHORT).show();
                counter++;
                TurnWifion();

                 }
            else
            {
                b1.setChecked(false);
                Toast.makeText(popup.this,"Turning Wifi OFF",Toast.LENGTH_SHORT).show();
                counter--;
                b1.setTextColor(Color.BLACK);
                TurnWifioff();
            }
        }
    });



    Button scan =(Button)findViewById(R.id.scanbutton);
    b2.setOnClickListener(new Button.OnClickListener() {
        @Override
        public void onClick(View v) {
            wifiManager.startScan();

        }
    });




}

private void TurnWifion() {



    WifiReceiver wifiReceiver = new WifiReceiver();
    registerReceiver(wifiReceiver, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
    wifiManager.startScan();

    Toast.makeText(popup.this,"Getting Scanned Result",Toast.LENGTH_SHORT).show();

}

private void TurnWifioff() {

}


class  WifiReceiver extends BroadcastReceiver {


    @Override
    public void onReceive(Context context, Intent intent) {

        List<ScanResult> scanResults = wifiManager.getScanResults();

        String[] scan_list = new String[scanResults.size()];

        for(int i =0 ;i <= scanResults.size();i++){

            scan_list[i]=((scanResults.get(i)).toString());
        }

        ListView lv = (ListView)findViewById(R.id.listView2);
        lv.setAdapter(new ArrayAdapter<String>(getApplicationContext(),android.R.layout.simple_expandable_list_item_1,scan_list));
    }
}

}