我创建了一个可以发送和接收文本并在textView中显示文本的应用程序。该应用程序可以在更早的时候完美运行，我似乎看不到为什么发生了什么变化，但是现在我在设置TextsView文本时得到了NPE。有趣的是，尽管它显示为非null并正确设置，然后由于某些未知原因再次运行相同的代码，但这一次textview为null。
我知道NPE是什么，为什么会发生。我只需要帮助找到代码为什么运行两次，以及为什么第二次运行textsview为null即可。
Textsview在类的顶部定义，然后在OnCreateView中设置。
班级：
public class Rel1 extends Fragment {
TextView textsView;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.rel1, container, false);
getContext().registerReceiver(smsReceiver, new IntentFilter("android.provider.Telephony.SMS_RECEIVED"));
textsView = view.findViewById(R.id.texts1);
return view;
}
public BroadcastReceiver smsReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
Bundle bundle = intent.getExtras();
SmsMessage[] msgs = null;
String str = "";
String num = null, msg = null;
if (bundle != null) {
//---retrieve the SMS message received---
Object[] pdus = (Object[]) bundle.get("pdus");
msgs = new SmsMessage[pdus.length];
for (int i = 0; i < msgs.length; i++) {
msgs[i] = SmsMessage.createFromPdu((byte[]) pdus[i]);
num = msgs[i].getOriginatingAddress();
msg = msgs[i].getMessageBody();
}
//---display the new SMS message---
Log.d("SmsReceiver", "onReceive: Message Received = " + msg + " msgs = " + msgs + " bundle = " + bundle);
Log.d("textsview", "onReceive: can SmsReceiver find texts view?" + textsView);
setMsg(msg, num, textsView);
}
}
};
public void setMsg(String msg, String num, TextView textsView) {
Log.d("SetMsg: ", "setMsg: msg = " + msg + " num = " + num);
Log.d("texts view", "setMsg: is textsview existing? : " + textsView);
if (textsView != null) {
Log.d("setMSG", "setMsg: Function called" + msg);
if (num.equals(txtPhoneNo.getText().toString()) || convNum(num).equals(txtPhoneNo.getText().toString())) {
Log.d("setmsg: ", "setMsg: num checks out");
if (msg.equals("REL 1 OFF==REL 2 OFF")) {
Log.d("Parse: ", "setMsg: REL 1 OFF==REL 2 OFF");
h = true;
w = true;
} else if (msg.equals("REL 1 ON==REL 2 OFF")) {
Log.d("Parse: ", "setMsg: REL 1 ON==REL 2 OFF");
h = false;
w = true;
} else if (msg.equals("REL 1 OFF==REL 2 ON")) {
Log.d("Parse: ", "setMsg: REL 1 OFF==REL 2 ON");
h = true;
w = false;
} else if (msg.equals("REL 1 ON==REL 2 ON")) {
Log.d("Parse: ", "setMsg: REL 1 ON==REL 2 ON");
h = false;
w = false;
} else {
Toast.makeText(getContext().getApplicationContext(),
"Check Number! Incorrect Message Recieved!",
Toast.LENGTH_LONG).show();
}
}
sendNotification(h, w);
if(h && w) {
textsView.setText(R.string.hON_wON);
//((EditText)view2.findViewById(R.id.texts1)).setText(R.string.hON_wON);
} else if (h && !w) {
textsView.setText(R.string.hON_wOFF);
//((EditText)view2.findViewById(R.id.texts1)).setText(R.string.hON_wOFF);
} else if (!h && w) {
textsView.setText(R.string.hOFF_wON);
//((EditText)view2.findViewById(R.id.texts1)).setText(R.string.hOFF_wON);
} else if (!h && !w) {
textsView.setText(R.string.hOFF_wOFF);
//((EditText)view2.findViewById(R.id.texts1)).setText(R.string.hOFF_wOFF);
}
}
}
@Override
public void onPause() {
getContext().unregisterReceiver(smsReceiver);
super.onPause();
}
@Override
public void onDestroy() {
getContext().unregisterReceiver(smsReceiver);
super.onDestroy();
}
@Override
public void onResume() {
getContext().registerReceiver(smsReceiver, new IntentFilter("android.provider.Telephony.SMS_RECEIVED"));
super.onResume();
}
Logcat： 请注意，代码如何运行两次，并且textsview在那里运行一次，之后就消失了
09-20 21:56:50.571 11037-11037/com.mypackage.myprogram D/SmsReceiver: onReceive: Message Received = REL 1 OFF==REL 2 ON msgs = [Landroid.telephony.SmsMessage;@5bd4de0 bundle = Bundle[{format=3gpp, pdus=[[B@a949899, slot=0, phone=0, rTime=1537477010526, subscription=1, upload_flag=1}]
09-20 21:56:50.571 11037-11037/com.mypackage.myprogram D/textsview: onReceive: can SmsReceiver find texts view?android.support.v7.widget.AppCompatTextView{2156868 V.ED..... ........ 0,628-720,834 #7f0800b8 app:id/texts1}
09-20 21:56:50.572 11037-11037/com.mypackage.myprogram D/SetMsg:: setMsg: msg = REL 1 OFF==REL 2 ON num = ###NUMBER OMMITTED
09-20 21:56:50.572 11037-11037/com.mypackage.myprogram D/texts view: setMsg: is textsview existing? : android.support.v7.widget.AppCompatTextView{2156868 V.ED..... ........ 0,628-720,834 #7f0800b8 app:id/texts1}
09-20 21:56:50.572 11037-11037/com.mypackage.myprogram D/setMSG: setMsg: Function calledREL 1 OFF==REL 2 ON
09-20 21:56:50.594 11037-11037/com.mypackage.myprogram D/ActivityThread: BDC-Calling finishReceiver: IIntentReceiver=38d2555
09-20 21:56:50.635 11037-11037/com.mypackage.myprogram D/SmsReceiver: onReceive: Message Received = REL 1 OFF==REL 2 ON msgs = [Landroid.telephony.SmsMessage;@936fb6a bundle = Bundle[{format=3gpp, pdus=[[B@aff885b, slot=0, phone=0, rTime=1537477010526, subscription=1, upload_flag=1}]
09-20 21:56:50.636 11037-11037/com.mypackage.myprogram D/textsview: onReceive: can SmsReceiver find texts view?null
09-20 21:56:50.636 11037-11037/com.mypackage.myprogram D/SetMsg:: setMsg: msg = REL 1 OFF==REL 2 ON num = ###NUMBER OMMITTED
09-20 21:56:50.636 11037-11037/com.mypackage.myprogram D/texts view: setMsg: is textsview existing? : null
任何人都可以给出一个原因，使它从一条消息中运行两次，并且第二次textsView为空吗？
答案 0 :(得分：0)
知道了。在版本2中，我将“文本”视图设置为R.id.textsview，该视图不存在，我要做的就是将其更改为R.id.texts1。