我希望當用戶激活互聯網進行操作,但我得到了以下錯誤:無法實例接收器沒有空的構造
java.lang.InstantiationException:不能實例類com.project.proj.NetworkChangeReceiver ;沒有空的構造
在活動課我寫了下面的
NetworkChangeReceiver net = new NetworkChangeReceiver(getBaseContext());
我要去哪裏錯了。請幫忙 !
public class NetworkChangeReceiver extends BroadcastReceiver
{
Context mContext;
public NetworkChangeReceiver(Context context)
{
mContext= context;
}
@Override
public void onReceive(final Context context, final Intent intent) {
String status = NetworkUtil.getConnectivityStatusString(context);
if (status == "Wifi enabled")
{
Database details=new Database(mContext);
details.open();
List<String> detailsId;
detailsId=details.getRecords();
retrieveValuesFromListMethod1(detailsId);
Toast.makeText(context, "working properly", Toast.LENGTH_SHORT).show();
}
Toast.makeText(context, status, Toast.LENGTH_SHORT).show();
}
public void retrieveValuesFromListMethod1(List detailsId)
{
Iterator itr = detailsId.iterator();
while(itr.hasNext())
{
//do something
}
}
}
你需要無參數的構造函數。 – nhaarman
只需添加一個構造函數不帶參數no? –
@niekbut然後我得到Nullpointer異常無法啓動reciever! – user3496326