我可以获取JSON数据，但无法在TextView中设置值。我正在设置数据显示空指针异常。< / p>
getUsersListData（）
public class Fee extends Fragment /*implements View.OnClickListener */ {
LinearLayout receipt1, receipt2, receipt3, receipt4;
LinearLayout receipt1detail, receipt2detail, receipt3detail, receipt4detail;
TextView statustextView;
ListView listViewfees, listviewfeedetail;
List<StudentFeeInformation> yourData = new ArrayList<StudentFeeInformation>();
public static final String Navigation_URL = "http://192.168.100.5:84/Api/financeApi/getAllFees";
String master_id;
TableLayout tableLayout;
TextView table_data1, table_data2;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.student_fees_listview, container, false);
setHasOptionsMenu(true);
receipt1 = (LinearLayout) view.findViewById(R.id.linear_receipt1_fee);
// receipt4 = (LinearLayout) view.findViewById(R.id.linear_receipt4_fee);
// receipt1detail = (LinearLayout) view.findViewById(R.id.receipt1_fee);
// receipt2detail = (LinearLayout) view.findViewById(R.id.receipt2_fee);
// receipt3detail = (LinearLayout) view.findViewById(R.id.receipt3_fee);
// receipt4detail = (LinearLayout) view.findViewById(R.id.receipt4_fee);
// receipt1.setOnClickListener(this);
// receipt2.setOnClickListener(this);
// receipt3.setOnClickListener(this);
// receipt4.setOnClickListener(this);
// receipt1detail.setVisibility(View.VISIBLE);
// receipt2detail.setVisibility(View.GONE);
// receipt3detail.setVisibility(View.GONE);
// receipt4detail.setVisibility(View.GONE);
statustextView = (TextView) view.findViewById(R.id.student_profile_fee_status);
SessionManagement sessionManagement = new SessionManagement(getContext());
master_id = sessionManagement.getMasterId();
listViewfees = (ListView) view.findViewById(R.id.list_student_fees);
tableLayout = (TableLayout) view.findViewById(R.id.simpleTableLayout);
table_data1 = (TextView) view.findViewById(R.id.student_profile_fee_description);
table_data2 = (TextView) view.findViewById(R.id.student_profile_fee_amount);
getUsersListData();
return view;
}
private void getUsersListData() {
String URL = Navigation_URL + "?id=" + master_id;
StringRequest stringRequest = new StringRequest(Request.Method.GET, URL,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
try {
String Descriptionlist;
String Amount = null;
ArrayList<StudentFeeInformation> student_list = new ArrayList<>();
ArrayList<StudentFeeInformation> student_list_description = new ArrayList<>();
JSONArray jArray = new JSONArray(response);
// studentFeeInformation = new StudentFeeInformation(response);
for (int i = 0; i < jArray.length(); i++) {
JSONObject jsonObject = jArray.getJSONObject(i);
String status = jsonObject.getString("Status");
String DateofReceiptIssued = jsonObject.getString("DateOfReciept").substring(0, 10);
String ReceiptNumber = jsonObject.getString("RecieptNo");
String FeeReceivedDate = jsonObject.getString("recivedDate").substring(0, 10);
String Description = jsonObject.getString("Description");
JSONArray jArray1 = new JSONArray(Description);
for (int j = 0; j < jArray1.length(); j++) {
JSONObject jsonObjectinner = jArray1.getJSONObject(j);
Descriptionlist = jsonObjectinner.getString("des");
Amount = jsonObjectinner.getString("Amount");
table_data1.setText(Amount); // its Showing the Null pointer exception
System.out.println(Descriptionlist);
System.out.println(Amount);
}
student_list.add(new StudentFeeInformation(status, DateofReceiptIssued, ReceiptNumber, FeeReceivedDate));
}
System.out.println("student_list size:" + student_list.size());
CustomFeeListStudentAdapter customFeeListStudentAdapter = new CustomFeeListStudentAdapter(getActivity(), student_list);
listViewfees.setAdapter(customFeeListStudentAdapter);
} catch (JSONException e) {
System.out.println("This is not good");
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// Toast.makeText(view.Fee.this, error.toString(), Toast.LENGTH_LONG).show();
}
}) {
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
Map<String, String> headers = new HashMap<String, String>();
return headers;
}
};
RequestQueue requestQueue = Volley.newRequestQueue(getContext());
requestQueue.add(stringRequest);
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
// TODO Auto-generated method stub
super.onCreateOptionsMenu(menu, inflater);
inflater.inflate(R.menu.dashboard, menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// handle item selection
switch (item.getItemId()) {
case R.id.action_settings:
// do s.th.
return true;
default:
return super.onOptionsItemSelected(item);
}
}
我的MOdel课程
public class StudentFeeInformation implements Serializable {
public String Status;
public String ReceiptIssuedDate;
public String ReceiptIssuedNumber;
public String FeeReceivedDate;
public String FeeDescription;
public String Amount;
public StudentFeeInformation(String status, String ReceiptissuedDate, String ReceiptissuedNumber, String FeereceivedDate, String amount) {
Status = status;
ReceiptIssuedDate = ReceiptissuedDate;
ReceiptIssuedNumber = ReceiptissuedNumber;
FeeReceivedDate = FeereceivedDate;
Amount = amount;
}
public String getStatus() {
return Status;
}
public void setStatus(String status) {
Status = status;
}
public String getReceiptIssuedDate() {
return ReceiptIssuedDate;
}
public void setReceiptIssuedDate(String receiptIssuedDate) {
ReceiptIssuedDate = receiptIssuedDate;
}
public String getReceiptIssuedNumber() {
return ReceiptIssuedNumber;
}
public void setReceiptIssuedNumber(String receiptIssuedNumber) {
ReceiptIssuedNumber = receiptIssuedNumber;
}
public String getFeeReceivedDate() {
return FeeReceivedDate;
}
public void setFeeReceivedDate(String feeReceivedDate) {
FeeReceivedDate = feeReceivedDate;
}
public String getFeeDescription() {
return FeeDescription;
}
public void setFeeDescription(String feeDescription) {
FeeDescription = feeDescription;
}
public String getAmount() {
return Amount;
}
public void setAmount(String amount) {
Amount = amount;
}
}
我的JSON
[
{
"MasterID": "E0017",
"StdID": 111,
"Status": "U",
"AmountPaid": 6645,
"Class": 8,
"DateOfReciept": "2017-01-01T00:00:00",
"Description": "[{\"des\":\"Admission\",\"Amount\":300},{\"des\":\"Monthly Fee\",\"Amount\":5400},{\"des\":\"Exam Fee\",\"Amount\":200},{\"des\":\"Extra Charge\",\"Amount\":400},{\"des\":\"Late Charge\",\"Amount\":345}]",
"RecieptNo": 1011,
"NAME": "Uzumaki Naruto",
"recivedDate": "2017-03-10T00:00:00",
"reciever": "Cynthia Irwin"
},
{
"MasterID": "E0017",
"StdID": 111,
"Status": "U",
"AmountPaid": 5600,
"Class": 8,
"DateOfReciept": "2017-03-01T00:00:00",
"Description": "[{\"des\":\"Exam Fee\",\"Amount\":200},{\"des\":\"Monthly Fee\",\"Amount\":5400}]",
"RecieptNo": 1012,
"NAME": "Uzumaki Naruto",
"recivedDate": "2017-03-06T00:00:00",
"reciever": "Cynthia Irwin"
}
]
布局
<TableLayout
android:id="@+id/simpleTableLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:stretchColumns="1"> <!-- stretch the second column of the layout-->
<TableRow
android:id="@+id/firstRow"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/student_profile_fee_description"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="left|center"
android:paddingLeft="70dp"
android:paddingTop="5dp"
android:text="Sports"
android:textSize="12sp" />
<TextView
android:id="@+id/student_profile_fee_amount"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="left|center"
android:paddingLeft="70dp"
android:paddingTop="5dp"
android:text="Sports"
android:textSize="12sp" />
</TableRow>
</TableLayout>
logcat 设置外部循环
3-16 16:31:01.037 9722-9722/com.example.user.mis W/IInputConnectionWrapper: finishComposingText on inactive InputConnection
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: DescriptionlistAdmission
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: Amount300
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: table_data1 null
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: DescriptionlistMonthly Fee
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: Amount5400
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: table_data1 null
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: DescriptionlistExam Fee
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: Amount200
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: table_data1 null
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: DescriptionlistExtra Charge
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: Amount400
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: table_data1 null
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: DescriptionlistLate Charge
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: Amount345
03-16 16:31:03.032 9722-9722/com.example.user.mis D/TAG: table_data1 null
03-16 16:31:03.033 9722-9722/com.example.user.mis D/AndroidRuntime: Shutting down VM
03-16 16:31:03.033 9722-9722/com.example.user.mis E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.user.mis, PID: 9722
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at com.example.user.mis.fragment.Fee$1.onResponse(Fee.java:175)
at com.example.user.mis.fragment.Fee$1.onResponse(Fee.java:130)
at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:60)
at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:30)
at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:99)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
我知道Value为null，但无法解决问题？
答案 0 :(得分：0)
如果不执行此操作，您是否初始化了table_data1
{{Item}}如果这样做已经发布了您的完整代码：）
答案 1 :(得分：0)
您可以通过编写日志来检查TextView table_data1是否为空。
Log.e（＆＃34; TestTAG＆＃34;，＆＃34; table_data1 ==＆＃34; + table_data1）
如果打印为null，则在调用 WebService 之前检查它是否已初始化，如果您正在执行所有操作，请检查您查找table_data1的id的视图是否包含此{{1是不是？
检查您的布局TextView是否有此TextView student_fees_listview
如果没有，那么你student_profile_fee_description布局错误。
答案 2 :(得分：0)
试试这个：
int Amount = jsonObjectinner.getInt("Amount");
Log.d("TAG","Descriptionlist"+Descriptionlist);
Log.d("TAG","Amount"+Amount);
if(table_data1!=null)
{
Log.d("TAG","table_data1 not null");
table_data1.setText(Amount+"");
}
else
{
Log.d("TAG","table_data1 null");
}
答案 3 :(得分：0)
使用http://www.jsonschema2pojo.org/创建回复课程 之后，通过调用get方法创建类的对象，您可以单独获取每个值。然后您可以随时随地使用它。希望它能帮到你。只需访问上面的链接并粘贴您的json，您就会知道如何继续。正确序列化您的响应数据。