為什么列表始終為空？

Question

在這段代碼中，我正在搜索wifi接入點並在文本視圖中顯示結果。...在三星手機上工作正常，但由於某些原因，如果使用其他手機，則列表始終為空。

您能幫助我了解為什么列表始終為空嗎？ 我將不勝感激。

public class MainActivity extends AppCompatActivity {

    Switch aswitch;
    int n=1;
    TextView text;
    WifiManager wifi;
    String message;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        aswitch=(Switch)findViewById(R.id.myswitch);
        wifi=(WifiManager)getSystemService(WIFI_SERVICE);
        text=(TextView)findViewById(R.id.mytv);

        aswitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                // do something, the isChecked will be
                // true if the switch is in the On position
                if (isChecked && !wifi.isWifiEnabled()) {
                    wifi.setWifiEnabled(true);
                    message="enabled";
                    text.setText(message);


                } else if (!isChecked && wifi.isWifiEnabled()){
                    wifi.setWifiEnabled(false);
                    message="disabled";
                    text.setText(message);
                }
            }
        });

            MyBroadcastReceiver broadcast=new MyBroadcastReceiver();
            registerReceiver(broadcast, new IntentFilter(wifi.SCAN_RESULTS_AVAILABLE_ACTION));



    }
    class MyBroadcastReceiver extends BroadcastReceiver{

        @Override
        public void onReceive(Context context, Intent intent) {
            StringBuffer stringBuffer=new StringBuffer();
            List<ScanResult> list=wifi.getScanResults();

            for(ScanResult scanResult:list){
                String ssid0 = scanResult.SSID;
                int rssi0 = scanResult.level;
                String rssiString0 = String.valueOf(rssi0);
                stringBuffer.append("\n SSID:" + ssid0 + "   RSSI:" + rssiString0 +"dBm");
                text.setText("yes");
            }
            text.setText(stringBuffer);
            if(wifi.isWifiEnabled()){
                wifi.startScan();
            }

        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

Answer 1

看起來很奇怪，您必須在清單中聲明精細或粗略的位置許可。 我前一段時間有這個問題。