我使用删除按钮从数据库中检索学生的信息（学生编号和 ID 和姓名），因此如果用户单击删除，它将显示列表中每个按钮的带有学生 ID 的 toast 消息。
但是我运行代码并单击删除按钮没有任何反应，日志中没有错误 cat 控制台中没有错误。我错过了什么，为什么会这样？我也尝试在 log cat 中显示此消息，但什么也没发生。
这是我的代码：
public class ManageSection extends ListActivity {
//ProgresogressDialog pDialog;
private ProgressDialog pDialog;
// Creating JSON Parser object
// Creating JSON Parser object
JSONParser jParser = new JSONParser(); //class
boolean x =true;
Button delete;
ArrayList<HashMap<String, String>> studentList;
//url to get all products list
private static String url_all_student = "http://10.0.2.2/SmsPhp/view_student_info.php";
String cl;
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_student = "student";
private static final String TAG_StudentID = "StudentID";
private static final String TAG_StudentNo = "StudentNo";
private static final String TAG_FullName = "FullName";
private static final String TAG_Avatar="Avatar";
HashMap<String, String> selected_student;
// course JSONArray
JSONArray student = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.manage_section);
studentList = new ArrayList<HashMap<String, String>>();
ListView list1 = getListView();
list1.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int pos, long l) {
selected_student =studentList.get(pos); //member of your activity.
delete =(Button)findViewById(R.id.DeleteStudent);
cl=selected_student.get(TAG_StudentID);
Log.d("id: ",cl);
delete.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v) {
Log.d("id: ",cl);
Toast.makeText(getBaseContext(),cl,Toast.LENGTH_LONG).show();
}
});
}
});
new LoadAllstudent().execute();
}
/**
* Background Async Task to Load all student by making HTTP Request
* */
class LoadAllstudent extends AsyncTask<String, String, String>
{
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(ManageSection.this);
pDialog.setMessage("Loading student. Please wait...");
pDialog.setIndeterminate(false);
}
/**
* getting All student from u r l
* */
@Override
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_student, "GET", params);
// Check your log cat for JSON response
Log.d("All student : ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1)
{
// student found
// Getting Array of course
student = json.getJSONArray(TAG_student);
// looping through All courses
for (int i = 0; i < student.length(); i++)//course JSONArray
{
JSONObject c = student.getJSONObject(i); // read first
// Storing each json item in variable
String StudentID = c.getString(TAG_StudentID);
String StudentNo = c.getString(TAG_StudentNo);
String FullName = c.getString(TAG_FullName);
// String Avatar = c.getString(TAG_Avatar);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_StudentID, StudentID);
map.put(TAG_StudentNo, StudentNo);
map.put(TAG_FullName, FullName);
// adding HashList to ArrayList
studentList.add(map);
}
} else {
x=false;
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all products
pDialog.dismiss();
if (x==false)
Toast.makeText(getBaseContext(),"no student" ,Toast.LENGTH_LONG).show();
ListAdapter adapter = new SimpleAdapter(
ManageSection.this, studentList,
R.layout.list_student, new String[] { TAG_StudentID,
TAG_StudentNo,TAG_FullName},
new int[] { R.id.StudentID, R.id.StudentNo,R.id.FullName});
setListAdapter(adapter);
// Updating parsed JSON data into ListView
}
}
}
和用于管理的 xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/bg_all_1" >
<!-- HEADER -->
<include
android:id="@+id/top_header"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_marginTop="90dp"
layout="@layout/layout_header" />
<!-- FOOTER -->
<!-- MAIN PART -->
<RelativeLayout
android:id="@+id/sub_content_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/top_header"
android:orientation="vertical" >
<ScrollView
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<ListView
android:id="@android:id/list"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="50dp"
android:gravity="left"
android:layout_marginTop="10dp" >
</ListView>
</ScrollView>
</RelativeLayout>
<LinearLayout
android:id="@+id/bottom_menu"
android:layout_width="wrap_content"
android:layout_height="80dp"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_marginBottom="38dp"
android:orientation="vertical" >
<include
android:layout_width="wrap_content"
android:layout_height="wrap_content"
layout="@layout/layout_footer" />
</LinearLayout>
</RelativeLayout>
列出学生 xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<!-- Student id (CourseID) - will be HIDDEN - used to pass to other activity -->
<TextView
android:id="@+id/StudentID"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:visibility="gone"
/>
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<!-- Name Label -->
<TextView
android:id="@+id/FullName"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingTop="6dip"
android:paddingLeft="6dip"
android:textSize="8dip"
android:textStyle="bold" />
<TextView
android:id="@+id/StudentNo"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="6dip"
android:paddingTop="6dip"
android:textSize="8dip"
android:textStyle="bold" />
<Button
android:id="@+id/DeleteStudent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:minHeight="10dip"
android:minWidth="50dip"
android:text="@string/deleteStudent"
android:textSize="8dp"
android:width="30dp"
>
</Button>
<Button
android:id="@+id/Alert"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:minHeight="10dip"
android:minWidth="50dip"
android:text="@string/Alert"
android:textSize="8dp"
android:width="30dp" >
</Button>
<RadioGroup
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<RadioButton
android:id="@+id/radio_pirates"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="onRadioButtonClicked"
android:text="@string/attendance"
android:textSize="8dp"
/>
</RadioGroup>
</LinearLayout>