Question

这是我的第一个问题，因为我是Android世界节目的新手

我想把wifi rssi读取并在列表中显示它我写下面的代码，当我在手机上运行时，程序停止并说“抱歉程序停止” 我不知道为什么???有人可以帮我吗???

public class MainActivity extends ActionBarActivity {

    ListView list;
    WifiManager wifiManager;
    IntentFilter filter;
    String wifi [];
    WifiScanClass myClass;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        list=(ListView)findViewById(R.id.list1);
        wifiManager=(WifiManager)getSystemService(Context.WIFI_SERVICE);
         myClass = new WifiScanClass();
                    registerReceiver(myClass,new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
                    wifiManager.startScan();
    }
    protected void onResume()
    {
        filter=new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
        registerReceiver(myClass,filter);
        super.onResume();
    }
    protected void onPause()
    {
        unregisterReceiver(myClass);
        super.onPause();
    }

    class WifiScanClass extends BroadcastReceiver {
        @SuppressLint("UseValueOf")
        public void onReceive(Context context, Intent intent) {
            List<ScanResult> listResult=wifiManager.getScanResults();
            wifi=new String[listResult.size()];
            int i;
            for (i=0;i<listResult.size();i++);
            wifi[i]=((listResult.get(i)).toString());
            list.setAdapter(new ArrayAdapter<String>(getApplicationContext(),android.R.layout.simple_list_item_1,wifi));

        }
    }
}

Answer 1

请为错误添加Logcat输出。问题的一个可能来源可能是需要在提供的上下文中调用getApplicationContext（）。因此，尝试使用context.getApplicationContext（）替换getApplicationContext（）。

Answer 2

public class MainActivity extends ActionBarActivity {

    ListView list;
    WifiManager wifiManager;
    IntentFilter filter;
    String wifi [];
    WifiScanClass myClass;



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




        list=(ListView)findViewById(R.id.list1);
        wifiManager=(WifiManager)getSystemService(Context.WIFI_SERVICE);
        myClass = new WifiScanClass();
        wifiManager.startScan();


    }


    protected void onResume()
    {
        filter=new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
        registerReceiver(myClass,filter);
        super.onResume();

    }

    protected void onPause()
    {

        unregisterReceiver(myClass);
        super.onPause();

    }

    class WifiScanClass extends BroadcastReceiver {


        @SuppressLint("UseValueOf")
        public void onReceive(Context context, Intent intent) {
            List<ScanResult> listResult=wifiManager.getScanResults();
            wifi=new String[listResult.size()];

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

                wifi[i]=((listResult.get(i)).toString());

            list.setAdapter(new ArrayAdapter<String>(getApplicationContext(),android.R.layout.simple_list_item_1,wifi));


        }
    }
}

最后我发现了错误

“;”在for循环中。

无线RSSI读数

2 个答案: