package com.example.ky.wifiscanner;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.wifi.ScanResult;

import android.net.wifi.WifiManager;
import android.os.Environment;
import android.os.SystemClock;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.method.ScrollingMovementMethod;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;

import static android.R.attr.data;
import static java.security.AccessController.getContext;
import static java.sql.DriverManager.println;

public class MainActivity extends AppCompatActivity {
    int num=1;
    WifiManager wifi;
    BroadcastReceiver receiver;
    TextView textView;
    Button button;
    Button button2;
    String ess = Environment.getExternalStorageState();
    String sdCardPath = null;
    ArrayList<String> data = new ArrayList<String>();
    String res;
  //  String first_receive_MAC[]=new String[200];
 //  float fisrst_receive_frequency[]=new float[200];
  // int first_receive_dBm[]=new int[200];
    long clicktime;
    long starttime;
    long finishtime;
    long intevertime;
    private static final float NS2S=1.0f/1000000000.0f;//나노초를 초 단위로
    float time;

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

        // Register Broadcast Receiver
        receiver = new WiFiScanReceiver();
        registerReceiver(receiver, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));


        if(ess.equals(Environment.MEDIA_MOUNTED)) {
            sdCardPath = Environment.getExternalStorageDirectory().getAbsolutePath();


            Toast.makeText(this,"SD Card stored in " + sdCardPath, Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(this,"SD Card not ready!"+ sdCardPath, Toast.LENGTH_SHORT).show();
        }


        textView =(TextView)findViewById(R.id.textView);
        textView.setMovementMethod(new ScrollingMovementMethod());
        button =(Button)findViewById(R.id.button);
        button2 =(Button)findViewById(R.id.button2);
        wifi=(WifiManager)getSystemService(Context.WIFI_SERVICE);
       // if(!wifi.isWifiEnabled())
     //     wifi.setWifiEnabled(true);


        button.setOnClickListener(new View.OnClickListener() {//저장버튼 이벤트 리스너
            @Override
            public void onClick(View v) { //저장 버튼이 눌렷을경우 데이터 저장.

               MediaScanner scanner = MediaScanner.newInstance(MainActivity.this);
            scanner.mediaScanning(sdCardPath +"/wifi.txt");

            }
        });




        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                BackgroundThread  thread = new BackgroundThread();
                clicktime = System.currentTimeMillis();


                thread.start();


            }
        });


    }

    public class WiFiScanReceiver extends BroadcastReceiver {

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


            List<ScanResult> results = wifi.getScanResults();


            finishtime = System.currentTimeMillis() - clicktime;
            intevertime = finishtime - starttime;

            println(String.valueOf(num) + "    " + starttime+"   "+finishtime + " / " + intevertime);

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

                ScanResult result = results.get(i);

                String bssid = result.BSSID;

                String level = String.valueOf(result.level);
                String res = bssid + "  " + level;

                data.add(res);

            }
            data.add(String.valueOf(num-1) + "================================================");
            //Toast.makeText(getApplicationContext(), "스캔완료" + String.valueOf(num - 1), Toast.LENGTH_LONG).show();

            File file = new File(sdCardPath);
            if (!file.exists()) {
                file.mkdirs();
            }
            try {
                FileOutputStream fos = new FileOutputStream(file + "/wifi.txt");

                for (int j = 0; j < data.size(); j++) {
                    //  String name=(i+1)+" "+a.get(i)+"\r\n";
                    String name = data.get(j) + "\r\n";

                    fos.write(name.getBytes());
                }
                Toast.makeText(getApplicationContext(), "저장완료", Toast.LENGTH_LONG).show();
                fos.close();

            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }


        }

    }

    class BackgroundThread extends Thread {//내부 클래스스

        public void run() {


            for (int i = 0; i< 20; i++) {
                try {

                    starttime = System.currentTimeMillis() - clicktime;
                    wifi.startScan();
                    BackgroundThread.sleep(1000);


                }

                catch (InterruptedException e) {

                }

            }
        }
    }

   


    public void println(String data) {

        textView.append(data + "\n");
    }




}

스레드를 사용하여 1초마다 와이파이를 스캔하려고 하는데요.. 앱을 실행하면 스캔 주기가 1초 3초3초4초 5초 6초 8초8초 이렇게 일정하지 않게 됩니다. 해결방법이 있나요? ㅠ