标签不起作用，为什么？

Question

我首先扫描所有可用的WiFi网络，然后输出信号强度和名称。但是我的标签没有按我希望的方式响应。我希望在第一个选项卡上进行扫描，但是当我选择第二个选项卡时，我希望它更加详细，我希望您可以获得所有信息，如mac地址，协议，加密等。为什么我的代码不能执行那我该怎么办？

public class MainActivity extends TabActivity {

    WifiManager wifiManager;
    WifiScanReceiver wifiReciever;
    String bssid;
    String ssid;
    INT channel;
    int level;
    ArrayAdapter adapter;
    ListView list;
    ArrayList<String> wifis;
    WifiInfo wifiInfo;
    TabHost tabHost;

    // TabSpec Names
    PRIVATE static final String TAB1 = "Tab1";
    private static final String TAB2 = "Tab2";
    private static final String TAB3 = "Tab3";

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

    tabHost = getTabHost();
    final TabHost.TabSpec inboxSpec = tabHost.newTabSpec(TAB1);
    inboxSpec.setIndicator(TAB1);
    inboxSpec.setContent(new Intent(this, Tab1.class));
    tabHost.addTab(inboxSpec);

    TabHost.TabSpec PriceSpec = tabHost.newTabSpec(TAB2);
    PriceSpec.setIndicator(TAB2);
    PriceSpec.setContent(new Intent(this,Tab2.class));
    tabHost.addTab(PriceSpec);

    TabHost.TabSpec DistanceSpec = tabHost.newTabSpec(TAB3);
    DistanceSpec.setIndicator(TAB3);
    DistanceSpec.setContent(new Intent(this,Tab3.class));
    tabHost.addTab(DistanceSpec);

    tabHost.setCurrentTab(0);
        list = (ListView) findViewById(R.id.text);
        wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        wifiReciever = new WifiScanReceiver();
        wifiInfo = wifiManager.getConnectionInfo();

        wifis = new ArrayList<String>(); //initialize wifis
        wifis.add("loading...");
        adapter = new ArrayAdapter<String>(getApplicationContext(),
                android.R.layout.simple_list_item_1, wifis);
        list.setAdapter(adapter);

        wifiManager.startScan(); //make sure this is the last call
list.setOnItemClickListener(new ListView.OnItemClickListener() {



    @Override
    public void onItemClick(AdapterView<?> parent, View view, INT position, long id) {
        switchTab(1);
    }

});};


    public void switchTab(int tab){
        tabHost.setCurrentTab(tab);
    }

    protected void onPause() {
        unregisterReceiver(wifiReciever);
        super.onPause();
    }

    public static int convertFrequencyToChannel(int freq) {
        if (freq >= 2412 && freq <= 2484) {
            return (freq - 2412) / 5 + 1;
        } else if (freq >= 5170 && freq <= 5825) {
            return (freq - 5170) / 5 + 34;
        } else {
            return -1;
        }
    }

    protected void onResume() {
        registerReceiver(wifiReciever, new IntentFilter(
                WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
        super.onResume();
    }


    public void tabs() {

    }

    class WifiScanReceiver extends BroadcastReceiver {
        @SuppressLint("UseValueOf")
        public void onReceive(Context c, Intent intent) {
            List<ScanResult> wifiScanList = wifiManager.getScanResults();
            //wifis = new String[wifiScanList.size()]; //remove this
            wifis.clear(); //add this
            for (int i = 0; i < wifiScanList.size(); i++) {
                ssid = wifiScanList.get(i).SSID; //Get the SSID
                level = wifiScanList.get(i).level;
                channel =wifiScanList.get(i).frequency;

                //use add here:
                wifis.add(ssid + " " + level + " " + convertFrequencyToChannel(channel)); //append to the other data
                wifis.toString();
            }

            adapter.notifyDataSetChanged(); //add this
            wifiManager.startScan(); //start a new scan to update values faster

            //ArrayAdapter adapter = new ArrayAdapter<String>(getApplicationContext(),
            //       android.R.layout.simple_list_item_1, wifis)
            //list.setAdapter(adapter);
        }
    }

}