我可能会问一个愚蠢的问题，但这是在花了很多时间来解决这个问题。希望有人可以建议。
我收到错误
TitleTxt.setText("Title: " + title);
TitleTxt为空。
package com.androidatc.customviewindrawer;
/**
*/
/**
* Copyright (c) 2015 Android ATC.
*
* Author: Android ATC Training Team.
*
* Source code in this project is provided for trainers of
* course AND-401 titled "Android Application Development".
*
* The is the source code for Lab 5 of the text book.
*
*/
import android.app.Activity;
import android.content.Intent;
import android.graphics.Color;
import android.net.Uri;
import android.os.Bundle;
//import android.support.v4.app.Fragment;
import android.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import com.androidatc.customviewindrawer.android.IntentIntegrator;
import com.androidatc.customviewindrawer.android.IntentResult;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.RequestHandle;
import com.loopj.android.http.TextHttpResponseHandler;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import java.io.IOException;
import java.io.StringReader;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import cz.msebera.android.httpclient.Header;
/**
* A simple {@link Fragment} subclass.
* Activities that contain this fragment must implement the
* {@link SearchCatFragment.OnFragmentInteractionListener} interface
* to handle interaction events.
* Use the {@link SearchCatFragment#newInstance} factory method to
* create an instance of this fragment.
*/
public class BarCodeFrag extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment SearchCatFragment.
*/
// TODO: Rename and change types and number of parameters
public static BarCodeFrag newInstance(String param1, String param2) {
BarCodeFrag fragment = new BarCodeFrag();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
public BarCodeFrag() {
// Required empty public constructor
}
//the custom view
private SearchView myView;
private Button scanBtn,detailsBtn;
private TextView formatTxt, contentTxt, TitleTxt, PublisherTxt, CreatorTxt, AvailabiltyTxt;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView = inflater.inflate(R.layout.fragment_barcode, container, false);
scanBtn = (Button) rootView.findViewById(R.id.scan_button);
formatTxt = (TextView) rootView.findViewById(R.id.scan_format);
contentTxt = (TextView) rootView.findViewById(R.id.scan_content);
detailsBtn = (Button) rootView.findViewById(R.id.scan_button);
TitleTxt = (TextView) rootView.findViewById(R.id.title);
PublisherTxt = (TextView) rootView.findViewById(R.id.Publisher);
CreatorTxt = (TextView) rootView.findViewById(R.id.Creator);
AvailabiltyTxt = (TextView) rootView.findViewById(R.id.Availability);
// myView.setSquareColor(Color.BLUE);
// myView.setLabelColor(Color.YELLOW);
// myView.setLabelText("Press Me");
scanBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// myView.setSquareColor(Color.GREEN);
// myView.setLabelColor(Color.MAGENTA);
// myView.setLabelText("Android ATC");
if (v.getId() == R.id.scan_button) {
//instantiate ZXing integration class
//IntentIntegrator scanIntegrator = new IntentIntegrator(getActivity());
IntentIntegrator scanIntegrator = new IntentIntegrator(BarCodeFrag.this);
//start scanning
scanIntegrator.initiateScan();
// startActivityForResult(scanIntegrator, 1888);
// scanIntegrator.parseActivityResult
} else {
//invalid scan data or scan canceled
Toast toast = Toast.makeText(getActivity().getApplicationContext(),
"No scan data received!", Toast.LENGTH_SHORT);
toast.show();
}
}
});
return rootView;
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mListener = (OnFragmentInteractionListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p/>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
public void onFragmentInteraction(Uri uri);
}
public void onActivityResult(int requestCode, int resultCode, Intent intent) {
//retrieve result of scanning - instantiate ZXing object
super.onActivityResult(requestCode, resultCode, intent);
IntentResult scanningResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent);
//check we have a valid result
// Toast.makeText(getActivity().getApplicationContext(), "Inside onActivityResult" , Toast.LENGTH_LONG).show();
if (scanningResult != null) {
//get content from Intent Result
String scanContent = scanningResult.getContents();
//get format name of data scanned
String scanFormat = scanningResult.getFormatName();
//output to UI
formatTxt.setText("FORMAT: " + scanFormat);
contentTxt.setText("CONTENT: " + scanContent);
// Toast.makeText(getActivity().getApplicationContext(), "Reply: " + scanFormat + ":" + scanContent, Toast.LENGTH_LONG).show();
CheckDetails(scanContent);
}
}
public void CheckDetails(String scanContent) {
//
final int DEFAULT_TIMEOUT = 200000 * 1000000000;
// Toast.makeText(getActivity().getApplicationContext(), "Scan Content : " + scanContent, Toast.LENGTH_LONG).show();
// Make RESTful webservice call using AsyncHttpClient object
AsyncHttpClient client = new AsyncHttpClient();
client.setTimeout(DEFAULT_TIMEOUT);
RequestHandle requestHandle = client.get("http://koha-startRecord=1&maximumRecords=10&recordSchema=dc", new TextHttpResponseHandler() {
@Override
public void onSuccess(int i, Header[] headers, String response) {
// Toast.makeText(getActivity().getApplicationContext(), "XML File: " + response, Toast.LENGTH_LONG).show();
readBarCode(response);
}
@Override
public void onFailure(int statusCode, Header[] headers, String response, Throwable error) {
Toast.makeText(getActivity().getApplicationContext(), "Status code :" + statusCode + "errmsg : " + error.getMessage(), Toast.LENGTH_LONG).show();
Toast.makeText(getActivity().getApplicationContext(), "Unexpected Error occcured! [Most common Error: Device might not be connected to Internet or remote server is not up and running]", Toast.LENGTH_LONG).show();
}
}
);
}
public void readBarCode(String response) {
DocumentBuilder builder = null;
try {
builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
InputSource src = new InputSource();
src.setCharacterStream(new StringReader(response));
Document doc = builder.parse(src);
//String available = doc.getElementsByTagName("zs:numberOfRecords").item(0).getTextContent();
String title = doc.getElementsByTagName("dc:title").item(0).getTextContent();
String creator1 = doc.getElementsByTagName("dc:creator").item(0).getTextContent();
String creator2 = doc.getElementsByTagName("dc:creator").item(1).getTextContent();
String publisher = doc.getElementsByTagName("dc:publisher").item(0).getTextContent();
String description = doc.getElementsByTagName("dc:description").item(0).getTextContent();
String availability = doc.getElementsByTagName("dc:duedate").item(0).getTextContent();
NodeList list = doc.getElementsByTagName("dc:duedate");
// NodeList available = doc.getElementsByTagName("dc:duedate/");
// Element element = doc.getDocumentElement();
src.setCharacterStream(new StringReader(response));
NodeList nodes = doc.getElementsByTagName("dc:duedate");
// print the text content of each child
// int cnt=0;
// // print the text content of each child
// for (int i = 0; i < nodes.getLength(); i++) {
// if(nodes.item(0).getNodeName().equals("dc:duedate") && nodes.item(i).getTextContent().trim().isEmpty()){
//// nodes.item(i).getTextContent().trim().length();
// cnt++;
// }
// }
int cnt=0;
for (int i = 0; i < nodes.getLength(); i++) {
if(nodes.item(i).getTextContent().trim().isEmpty()){
cnt++;
}
}
Log.e("TAGLOG", "" + cnt);
// String expiry = doc.getElementsByTagName("dateexpiry").item(0).getTextContent();
// Toast.makeText(getActivity().getApplicationContext(), "You are successfully logged in!", Toast.LENGTH_LONG).show();
Toast.makeText(getActivity().getApplicationContext(), "Title : " + title +
"\n" + "Publisher : " + publisher +
"\n" + "Creator : " + creator1 + "," + creator2 +
"\n" + "Description : " + description +
"\n" + "Total : " + list.getLength() +
"\n" + "Available : " + cnt
,Toast.LENGTH_LONG).show();
TitleTxt.setText("Title: " + title);
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
fragment_barcode.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#ffffff"
android:orientation="vertical"
tools:context="com.androidatc.customviewindrawer.BarCodeFrag"
android:weightSum="1">
<Button
android:id="@+id/scan_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:text="@string/scan"
android:layout_gravity="center_horizontal" />
<TextView
android:id="@+id/scan_format"
android:layout_width="94dp"
android:layout_height="40dp"
android:textIsSelectable="true"
android:layout_centerHorizontal="true"
android:layout_below="@id/scan_button"
android:layout_gravity="center_horizontal"
android:text="Format" />
<TextView
android:id="@+id/scan_content"
android:layout_width="83dp"
android:layout_height="40dp"
android:textIsSelectable="true"
android:layout_centerHorizontal="true"
android:layout_below="@id/scan_format"
android:layout_weight="0.03"
android:layout_gravity="center_horizontal"
android:text="Content" />
<TextView
android:id="@+id/Title"
android:layout_width="94dp"
android:layout_height="40dp"
android:textIsSelectable="true"
android:layout_centerHorizontal="true"
android:layout_below="@id/title"
android:layout_gravity="center_horizontal"
android:text="Title" />
<TextView
android:id="@+id/Publisher"
android:layout_width="83dp"
android:layout_height="40dp"
android:textIsSelectable="true"
android:layout_centerHorizontal="true"
android:layout_below="@id/Publisher"
android:layout_weight="0.03"
android:layout_gravity="center_horizontal"
android:text="Publisher" />
<TextView
android:id="@+id/Creator"
android:layout_width="94dp"
android:layout_height="40dp"
android:textIsSelectable="true"
android:layout_centerHorizontal="true"
android:layout_below="@id/Creator"
android:layout_gravity="center_horizontal"
android:text="Creator" />
<TextView
android:id="@+id/Availability"
android:layout_width="83dp"
android:layout_height="40dp"
android:textIsSelectable="true"
android:layout_centerHorizontal="true"
android:layout_below="@id/Availability"
android:layout_weight="0.03"
android:layout_gravity="center_horizontal"
android:text="Availablity" />
</LinearLayout>
答案 0 :(得分：3)
更改
TitleTxt = (TextView) rootView.findViewById(R.id.title);
到
TitleTxt = (TextView) rootView.findViewById(R.id.Title);
或
<TextView
android:id="@+id/Title"
到
<TextView
android:id="@+id/title"
答案 1 :(得分：1)
将您的标题文字ID更改为android:id="@+id/title"小写，因为您在java代码中使用TitleTxt = (TextView) rootView.findViewById(R.id.title);