在横向模式下强制关闭，但在纵向中不强制关闭

Question

I have an application which shows a list of items in runtime. When the user presses a Button , all selected items should be deleted (selection determined by CheckBox ). In portrait mode everything works well, but when I switch to landscape mode when the number of rows are more than 3 , pressing the delete button gets the Force Close Exception and I am unable to print the stack trace. When there are 3 or less rows it works perfectly! I've written the layout for both layout (portrait) and layout-land directories. Code and Layouts are as follows:

Here is the handler for Delete Button:

   Button DeleteGoods=(Button)findViewById(R.id.DeleteSelectedGoodsButton);
   DeleteGoods.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {
            CheckBox cbx = (CheckBox)listView.findViewById(R.id.ChkOrder);
            int firstPosition = listView.getFirstVisiblePosition();
                for (int i = firstPosition; i < listView.getCount(); i++) {

                    View v1 = listView.getChildAt(i);

                    cbx = (CheckBox)v1.findViewById(R.id.ChkOrder);
                    if(cbx.isChecked())
                        checkedItemPosition=i;                  
                }
                try {

                    DeleteCheckedItem(checkedItemPosition);

                    Toast.makeText(getApplicationContext(),"The selected order has been deleted successfully.", Toast.LENGTH_SHORT).show();

                    finish();
                    startActivity(getIntent());
                } catch (Exception e) {

                    Toast.makeText(getApplicationContext(), e.toString(), Toast.LENGTH_LONG).show();
                }


        }

    });

Here is the layout in landscape mode:

<?xml version="1.0" encoding="utf-8"?>

    <RelativeLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:background="#000000" >
        <Button 
            android:id="@+id/DeleteSelectedGoodsButton"
            android:layout_width="150dp"
            android:layout_height="45dp"
            android:text="@string/DeleteSelectedGoods"
            android:layout_alignParentTop="true"
            android:layout_alignParentLeft="true" />
        <Button 
            android:id="@+id/ConfirmDelete"
            android:layout_width="150dp"
            android:layout_height="45dp"
            android:text="@string/ConfirmDeleteButton"
            android:layout_alignParentTop="true"
            android:layout_centerHorizontal="true" />
        <Button 
            android:id="@+id/CancelButton"
            android:layout_width="150dp"
            android:layout_height="45dp"
            android:text="@string/CancelButton"
            android:layout_alignParentTop="true"
            android:layout_alignParentRight="true" />
        <TextView 
            android:id="@+id/aa"
            android:layout_height="wrap_content"
            android:layout_width="wrap_content"
            android:layout_below="@id/CancelButton" />

        <TextView 
            android:id="@+id/GOODNAME_CELL"
            android:layout_width="180dp"
            android:layout_height="wrap_content"
            android:background="@drawable/border"
            android:textSize="18dp"
            android:text="Order"
            android:paddingLeft="5dp"
            android:layout_below="@id/aa"
            android:layout_alignParentLeft="true" />
         <TextView 
            android:id="@+id/GOODUNITPRICE_CELL"
            android:layout_width="180dp"
            android:layout_height="wrap_content"
            android:background="@drawable/border"
            android:textSize="18dp"
            android:text="Unit Price"
            android:paddingLeft="5dp"
            android:layout_below="@id/aa"
            android:layout_toRightOf="@id/GOODNAME_CELL" />
         <TextView 
            android:id="@+id/QUANTITYCELL"
            android:layout_width="120dp"
            android:layout_height="wrap_content"
            android:background="@drawable/border"
            android:textSize="18dp"
            android:text="Quantity"
            android:paddingLeft="5dp"
            android:layout_below="@id/aa"
            android:layout_toRightOf="@id/GOODUNITPRICE_CELL" />
         <ListView 
        android:id="@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        style="@style/CodeFont"
        android:layout_alignParentLeft="true"
        android:layout_below="@id/GOODUNITPRICE_CELL" />

         <TextView
            android:id="@+id/TotalPriceTextview"
            android:layout_width="600dp"
            android:layout_height="wrap_content"
            android:text=""
            android:layout_alignParentBottom="true"
            android:layout_centerHorizontal="true"
            android:background="@drawable/back"
            android:textColor="#FFFFFF"
            android:textSize="20dp" />

    </RelativeLayout>

This is the exception I am getting:

02-19 10:07:11.398: E/AndroidRuntime(4335): FATAL EXCEPTION: main
02-19 10:07:11.398: E/AndroidRuntime(4335): java.lang.NullPointerException
02-19 10:07:11.398: E/AndroidRuntime(4335):     at com.example.nfc.PrepopSqliteDbActivity$1.onClick(PrepopSqliteDbActivity.java:117)
02-19 10:07:11.398: E/AndroidRuntime(4335):     at android.view.View.performClick(View.java:2552)
02-19 10:07:11.398: E/AndroidRuntime(4335):     at android.view.View$PerformClick.run(View.java:9229)
02-19 10:07:11.398: E/AndroidRuntime(4335):     at android.os.Handler.handleCallback(Handler.java:587)
02-19 10:07:11.398: E/AndroidRuntime(4335):     at android.os.Handler.dispatchMessage(Handler.java:92)
02-19 10:07:11.398: E/AndroidRuntime(4335):     at android.os.Looper.loop(Looper.java:138)
02-19 10:07:11.398: E/AndroidRuntime(4335):     at android.app.ActivityThread.main(ActivityThread.java:3701)
02-19 10:07:11.398: E/AndroidRuntime(4335):     at java.lang.reflect.Method.invokeNative(Native Method)
02-19 10:07:11.398: E/AndroidRuntime(4335):     at java.lang.reflect.Method.invoke(Method.java:507)
02-19 10:07:11.398: E/AndroidRuntime(4335):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:878)
02-19 10:07:11.398: E/AndroidRuntime(4335):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:636)
02-19 10:07:11.398: E/AndroidRuntime(4335):     at dalvik.system.NativeStart.main(Native Method)
02-19 10:07:11.408: W/ActivityManager(1768):   Force finishing activity com.example.nfc/.PrepopSqliteDbActivity
02-19 10:07:11.909: W/ActivityManager(1768): Activity pause timeout for HistoryRecord{40b2ed78 com.example.nfc/.PrepopSqliteDbActivity}
02-19 10:07:16.353: I/InputDispatcher(1768): Application is not responding: Window{40a73e60 com.example.nfc/com.example.nfc.PrepopSqliteDbActivity paused=false}.  5004.7ms since event, 5004.4ms since wait started
02-19 10:07:16.353: I/InputDispatcher(1768): Dropping event because the pointer is not down.
02-19 10:07:16.353: I/InputDispatcher(1768): Dropping event because the pointer is not down.
02-19 10:07:16.353: I/WindowManager(1768): Input event dispatching timed out sending to com.example.nfc/com.example.nfc.PrepopSqliteDbActivity
02-19 10:07:16.353: I/ActivityManager(1768): Crashing app skipping ANR: ProcessRecord{40a1b188 4335:com.example.nfc/10003} keyDispatchingTimedOut
02-19 10:07:21.428: W/ActivityManager(1768): Launch timeout has expired, giving up wake lock!
02-19 10:07:21.908: W/ActivityManager(1768): Activity idle timeout for HistoryRecord{40a1b7d8 com.example.nfc/.Buy}
02-19 10:07:26.963: I/touchd(1518): 'ab8500_usb' is online
02-19 10:07:26.963: I/touchd(1518): handling_uevent: event is 1

Edit

This is line 117:

DeleteCheckedItem(checkedItemPosition);

and this is the method's body:

private void DeleteCheckedItem(int chkPosition)
{   
    String strName=goods.get(chkPosition).get(GOOD_NAME);
    String strPrice=goods.get(chkPosition).get(GOOD_UNITPRICE);
    String strQuantity=goods.get(chkPosition).get(QUANTITY);
    String whereClause = "GOOD_NAME = ? AND GOOD_UNITPRICE= ? AND QUANTITY= ?";
    String[] whereArgs = {strName,strPrice,strQuantity};
    database.delete(TABLE_NAME, whereClause, whereArgs);
}

Answer 1

Is checkedItemPosition an int or an Integer ?

My guess is its an Integer that was initialized to null .

When you rotate, the activity is recreated and your checkedItemPosition was reinitialized to null .

Then you enter your for-loop, but none of the Checkbox views were checked so your checkedItemPosition is still null .

You try to call DeleteItemChecked on a null while it expects a primitive int and voila: NullPointerException .

Solution: initialize checkedItemPosition to 0 .

Answer 2

I encountered this kind of problem. My theory is related to the observation of Shadi

Portrait mode can display more rows than in landscape mode. And since you iterate the listview item count and try to get the view on the said position. If the view or item of the listview is not visible in the window/phone screen. There is possibility that you can get null values. getView() method of an adapter is called every scrolling, since initialization or recreating listview items is in getView() without proper calling in getView() method items that are not visible in window/phone screen is not initialized. You can use the method in listview: getLastVisiblePosition() to limit the number of item you will iterate to the listview.

Hope this will help you. Regards.

Answer 3

It looks like either database or TABLE_NAME is null . Add these lines before line 117 to test:

if (strName == null)
    Log.w("Test", "strName is NULL");
if (strPrice == null)
    Log.w("Test", "strPrice is NULL");
if (strQuantity == null)
    Log.w("Test", "strQuantity is NULL");
if (TABLE_NAME == null)
    Log.w("Test", "TABLE_NAME is NULL");
if (whereClause == null)
    Log.w("Test", "whereClause is NULL. WTF!");
if (whereArgs == null)
    Log.w("Test", "whereArgs is NULL. WTF!");
if (database == null)
    Log.w("Test", "database is NULL");

Answer 4

Got the problem and the solution is as below. when you rotate the screen the Adapter is getting initialized again and the previous array is getting cleaned. what you can do is put the onConfigurationChange() in the activity and try to check the output.

Answer 5

Looking at your code, what happens if delete is pressed but nothing is checked?

Getting to your question, is it possible that the checked item is not visible once delete is pressed? If so, because of View recycling (a scary, if clever, thing), it might not actually exist when you get to the delete button code, so you need to be careful about querying views at that point. It might be wiser to build up a "current selected list" as selections are made (and unmade) so that when delete is pressed you no longer have to query any views.

As an aside, it also looks like it will only delete the first checked item, but I may have missed something there.

Answer 6

Have you specified the handling of config changes in the Manifest file, if not please do so by adding: android:configChanges="keyboardHidden|orientation to your activity.

Please paste logcat, that will provide more info.. Good luck..