應用程序關閉錯誤java.lang.ClassCastException：android.widget.TableRow

Question

這是TeacherLoginPage.java它oncreate通過從數據庫中獲取數據來設置佈局。在onCreate方法中，我已經分配了檢查的ID使用setid（）方法的方框。 這裏的問題是當我點擊應用程序強制關閉的更新按鈕時。 我認爲行cbArray.add((CheckBox) findViewById(resId));不起作用。 我應該寫作（R.id.resId）嗎？

TeacherLoginPage.java

LinearLayout my_layout = (LinearLayout) findViewById(R.id.layout_checklist); 

    for (int i = 0; i < Array_Count; i++) { 
     TableRow row = new TableRow(this); 
     row.setId(i); 
     row.setLayoutParams(new LayoutParams(
       android.widget.TableRow.LayoutParams.FILL_PARENT, 
       android.widget.TableRow.LayoutParams.WRAP_CONTENT)); 

     CheckBox checkBox = new CheckBox(this); 

     checkBox.setId(i); 
     checkBox.setText(Roll_array.get(i)); 
     row.addView(checkBox); 
     my_layout.addView(row); 
    } 

public void onClick(View v) { 
     // TODO Auto-generated method stub 

     ArrayList<CheckBox> cbArray = new ArrayList<CheckBox>(); 
     int[] cvalue = null; 
     for (int j = 0; j < Array_Count; j++) { 
      int resId = getResources().getIdentifier(String.valueOf(j), "id", getPackageName()); 
      cbArray.add((CheckBox) findViewById(resId)); 
      cvalue[j] = toNumericalValue(cbArray.get(j).isChecked()); 
     } 
     insertAttendanceDatabase(TeacherLoggedInPage.this, cvalue); 

    } 

    private void insertAttendanceDatabase(
      TeacherLoggedInPage teacherLoggedInPage, int[] cvalue) { 
     // TODO Auto-generated method stub 

     SQLiteDatabase db = myDb.getWritableDatabase(); 

     int length = cvalue.length; 

     ContentValues cv = new ContentValues(); 
     cv.put("teacher_id", t_id); 
     cv.put("time", DateFormat.getDateTimeInstance().format(new Date())); 
     for (int i = 0; i < cvalue.length; i++) { 

      cv.put(Roll_array.get(i), cvalue[i]); 
     } 

     try { 
      db.insert(DbHelper.ATTENDANCE_TABLE, null, cv); 

     } catch (Exception e) { 
      e.printStackTrace(); 
     } 

    } 

    private int toNumericalValue(boolean checked) { 
     // TODO Auto-generated method stub 
     if (checked) 
      return 1; 
     else 
      return 0; 
    } 

這裏的logcat的

08-12 04:17:14.970: D/AndroidRuntime(385): Shutting down VM 
08-12 04:17:14.999: W/dalvikvm(385): threadid=1: thread exiting with uncaught exception (group=0x4001d800) 
08-12 04:17:15.009: E/AndroidRuntime(385): FATAL EXCEPTION: main 
08-12 04:17:15.009: E/AndroidRuntime(385): java.lang.ClassCastException: android.widget.TableRow 
08-12 04:17:15.009: E/AndroidRuntime(385): at com.example.attendancesystem.TeacherLoggedInPage.onClick(TeacherLoggedInPage.java:123) 
08-12 04:17:15.009: E/AndroidRuntime(385): at android.view.View.performClick(View.java:2408) 
08-12 04:17:15.009: E/AndroidRuntime(385): at android.view.View$PerformClick.run(View.java:8816) 
08-12 04:17:15.009: E/AndroidRuntime(385): at android.os.Handler.handleCallback(Handler.java:587) 
08-12 04:17:15.009: E/AndroidRuntime(385): at android.os.Handler.dispatchMessage(Handler.java:92) 
08-12 04:17:15.009: E/AndroidRuntime(385): at android.os.Looper.loop(Looper.java:123) 
08-12 04:17:15.009: E/AndroidRuntime(385): at android.app.ActivityThread.main(ActivityThread.java:4627) 
08-12 04:17:15.009: E/AndroidRuntime(385): at java.lang.reflect.Method.invokeNative(Native Method) 
08-12 04:17:15.009: E/AndroidRuntime(385): at java.lang.reflect.Method.invoke(Method.java:521) 
08-12 04:17:15.009: E/AndroidRuntime(385): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
08-12 04:17:15.009: E/AndroidRuntime(385): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
08-12 04:17:15.009: E/AndroidRuntime(385): at dalvik.system.NativeStart.main(Native Method) 
08-12 04:17:38.108: I/Process(385): Sending signal. PID: 385 SIG: 9 

Answer 1

你的問題是你設置你的ID兩次：

row.setId(i); 

後來

checkBox.setId(i); 

如果你什麼findViewById(resId)是正在發生的事情，然後它返回找到的第一個元素，這個ID是012如您所料，，而不是CheckBox。因此ClassCastException。

Answer 2

你正在努力蒙上了TableRow到CheckBox。確保ID指向一個CheckBox

Answer 3

這裏是點，您指定的ID爲TableRow較早，但隨後當你從渣油檢索，你投進去CheckBox造成的問題。檢查：

for (int i = 0; i < Array_Count; i++) { 
     TableRow row = new TableRow(this); 
     row.setId(i); 
     row.setLayoutParams(new LayoutParams(
       android.widget.TableRow.LayoutParams.FILL_PARENT, 
       android.widget.TableRow.LayoutParams.WRAP_CONTENT)); 

這：

ArrayList<CheckBox> cbArray = new ArrayList<CheckBox>(); 
     int[] cvalue = null; 
     for (int j = 0; j < Array_Count; j++) { 
      int resId = getResources().getIdentifier(String.valueOf(j), "id", getPackageName()); 
      cbArray.add((CheckBox) findViewById(resId)); 
      cvalue[j] = toNumericalValue(cbArray.get(j).isChecked()); 
     } 

希望它能幫助。

Answer 4

您正在爲TableRow和複選框分配相同的ID。作爲

row.setId(i); 

checkBox.setId(i); 

只是評論//row.setId(i);