As an experiment, I tried removing the GListView from it's parent
LinearLayout when I no longer needed it. When I did this, the garbage
collector was then able to recycle the parent (the LinearLayout), but
the GListView remained in memory and was not freed.
Using the Memory Analyzer, I can list the incoming references for one
of the GListViews which should be freed but is not:
Class
Name |
Shallow Heap | Retained Heap
-------------------------------------------------------------------------------------------------------
com.gabysoft.system.GListView @ 0x43e6fec8
Unknown | 672 | 3,432
|- host android.view.View$ScrollabilityCache @
0x43e701b8 | 80 | 584
|- this$0 android.widget.AbsListView$RecycleBin @
0x43e70488 | 40 | 96
|- mCallback android.graphics.drawable.StateListDrawable @
0x43e70500 | 64 | 1,464
|- this$0 android.widget.AdapterView$AdapterDataSetObserver @
0x43e70d10| 16 | 16
'- Total: 4
entries
| |
-------------------------------------------------------------------------------------------------------
Does this give anyone a clue as to where the problem might be? Surly
I must be doing something wrong here. There cannot be this kind of
leak in general can there?
Thanks.
On Oct 21, 5:47 pm, John Gaby <jg...@gabysoft.com> wrote:
> I have already tried making the ListAdapter a completely separate
> public class, and it does not seem to help. I can post that code, if
> it would be helpful (perhaps I have something wrong with it).
>
> Thanks.
>
> On Oct 21, 5:33 pm, Mark Murphy <mmur...@commonsware.com> wrote:
>
> > Move your ListAdapter to a public class or a static inner class of
> > your Activity, and see if that helps. A ListView being its own adapter
> > is not a well-trod path.
>
> > On Thu, Oct 21, 2010 at 8:04 PM, John Gaby <jg...@gabysoft.com> wrote:
> > > I am still struggling with a memory leak associated with a ListView.
> > > I have created the following small program which exhibits this
> > > behavior.
>
> > > What I do is create 2 LinearLayouts. The first has a Button and a
> > > GListView control. The code for GListView is below, but it just sub-
> > > classes ListView, and implements the ListAdapter interface. When the
> > > GListView is created, it sets it's adapter to itself.
>
> > > Now when you press the button I switch to the second LinearLayout.
> > > This layout has only a single button. When you press this button, I
> > > create a new 1st layout with a new GListView and set it as the active
> > > view.
>
> > > Run the program, and switch between the two views 20 times. Then
> > > bring up the DDMS and force a garbage collection. Then Dump the heap,
> > > and use the Memory Analyzer and you will find 21 GListView objects
> > > remaining. That is, the 20 GListViews that are not longer connected
> > > to anything have NOT been freed.
>
> > > Now if I comment out the 'setAdapter(this)' function in the GListView
> > > constructor and repeat the above, I find that there is only 1
> > > GListView that remains. That is, in this case, all of the unused
> > > GListViews have been properly recycled.
>
> > > Someone suggested that I create a private class within my GListView to
> > > handle the ListAdapter interface, and I tried that, but it did not
> > > help.
>
> > > Surely there is some way to make these objects go away when they are
> > > no longer used anywhere. (Isn't that what garbage collection is all
> > > about?)
>
> > > Any help would be appreciated. I am really pulling my hair out on
> > > this one.
>
> > > Thanks.
>
> > > /*
> > > * Activity
> > > */
>
> > > package com.gabysoft.memoryleak;
>
> > > import android.app.Activity;
> > > import android.os.Bundle;
> > > import android.view.View;
> > > import android.widget.Button;
> > > import android.widget.LinearLayout;
> > > import android.widget.ListView;
>
> > > public class MemoryLeak extends Activity implements
> > > android.view.View.OnClickListener
> > > {
> > > LinearLayout ll2;
> > > boolean page2 = false;
>
> > > private LinearLayout CreateLayout()
> > > {
> > > LinearLayout ll = new LinearLayout(this);
>
> > > Button btn1 = new Button(this);
> > > ListView lv = new GListView(this);
>
> > > btn1.setText("Press");
> > > btn1.setLayoutParams(new LinearLayout.LayoutParams(100, 40));
> > > btn1.setOnClickListener(this);
>
> > > ll.addView(btn1);
> > > ll.addView(lv);
>
> > > return(ll);
> > > }
>
> > > /** Called when the activity is first created. */
> > > �...@override
> > > public void onCreate(Bundle savedInstanceState)
> > > {
> > > super.onCreate(savedInstanceState);
>
> > > CreateLayout();
>
> > > LinearLayout ll = CreateLayout();
> > > ll2 = new LinearLayout(this);
>
> > > Button btn2 = new Button(this);
>
> > > btn2.setText("Back");
> > > btn2.setLayoutParams(new LinearLayout.LayoutParams(100, 40));
> > > btn2.setOnClickListener(this);
>
> > > ll2.addView(btn2);
>
> > > setContentView(ll);
> > > }
>
> > > �...@override
> > > public void onClick(View v)
> > > {
> > > if (page2)
> > > {
> > > LinearLayout ll = CreateLayout();
>
> > > setContentView(ll);
>
> > > page2 = false;
> > > }
> > > else
> > > {
> > > setContentView(ll2);
> > > page2 = true;
> > > }
> > > }
>
> > > }
>
> > > /*
> > > * GListView
> > > */
> > > package com.gabysoft.memoryleak;
>
> > > import android.content.Context;
> > > import android.database.DataSetObserver;
> > > import android.view.View;
> > > import android.view.ViewGroup;
> > > import android.widget.AdapterView;
> > > import android.widget.ListAdapter;
> > > import android.widget.ListView;
> > > import android.widget.TextView;
>
> > > public class GListView extends ListView implements ListAdapter
> > > {
> > > Context m_context;
> > > DataSetObserver m_observer = null;
>
> > > public GListView(Context context)
> > > {
> > > super(context);
>
> > > m_context = context;
>
> > > setAdapter(this);
>
> > > setChoiceMode(CHOICE_MODE_SINGLE);
> > > }
>
> > > /*
> > > * ListAdapter
> > > */
>
> > > �...@override
> > > public boolean areAllItemsEnabled()
> > > {
> > > return true;
> > > }
>
> > > �...@override
> > > public boolean isEnabled(int position)
> > > {
> > > return true;
> > > }
>
> > > �...@override
> > > public int getCount()
> > > {
> > > return(0);
> > > }
>
> > > �...@override
> > > public Object getItem(int position)
> > > {
> > > return null;
> > > }
>
> > > �...@override
> > > public long getItemId(int position)
> > > {
> > > return(position);
> > > }
>
> > > �...@override
> > > public int getItemViewType(int position)
> > > {
> > > return 0;
> > > }
>
> > > �...@override
> > > public View getView(int position, View convertView, ViewGroup
> > > parent)
> > > {
> > > TextView tv = new TextView(m_context);
>
> > > tv.setText("Item");
>
> > > return(tv);
> > > }
>
> > > �...@override
> > > public int getViewTypeCount()
> > > {
> > > return 1;
> > > }
>
> > > �...@override
> > > public boolean hasStableIds()
> > > {
> > > return false;
> > > }
>
> > > �...@override
> > > public boolean isEmpty()
> > > {
> > > return false;
> > > }
>
> > > �...@override
> > > public void registerDataSetObserver(DataSetObserver observer)
> > > {
> > > m_observer = observer;
> > > }
>
> > > �...@override
> > > public void unregisterDataSetObserver(DataSetObserver observer)
> > > {
> > > m_observer = null;
> > > }
> > > }
>
> > > --
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>
> > --
> > Mark Murphy (a Commons
> > Guy)http://commonsware.com|http://github.com/commonsguyhttp://commonsware.com/blog|http://twitter.com/commonsguy
>
> > Android App Developer Books:http://commonsware.com/books
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