Android获取周围WIFI热点服务

public class MainActivity extends AppCompatActivity {

  ArrayList list;  //存放周围wifi热点对象的列表
  WifiManager wifiManager;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    wifiManager = (WifiManager) getSystemService(WIFI_SERVICE);  //获得系统wifi服务
    list = (ArrayList)wifiManager.getScanResults();
    sortByLevel(list);
    init();
  }

  private void init(){
    TextView tv1=(TextView)findViewById(R.id.tv1);
    TextView tv2=(TextView)findViewById(R.id.tv2);
    TextView tv3=(TextView)findViewById(R.id.tv3);

    if (list.get(0).SSID != null && list.get(1).SSID != null){
      tv1.setText("信号最强为"+list.get(0).SSID);
      tv2.setText("信号第二位："+list.get(1).SSID);
      tv3.setText("共有"+list.size()+"个wifi");
    }

  }

  //将搜索到的wifi根据信号强度从强到弱进行排序
  private void sortByLevel(ArrayList list) {
    for(int i=0;i

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