具有SimpleAdapter的Android ListView泄漏内存

Question

This is a followup to my earlier question ( Android memory leak? ) after doing some research and following some of the steps suggested.

My application has a UI loop in which a user clicks a ListView item, which draws another ListView after querying a web api. Clicking on an item will draw up another ListView. This process can be repeated many times by a user without finishing the activity.

Here is a code snippet of how I am populating a ListView with SimpleAdapter..

//* Add available times value using array.length()
        List<Map<String,Object>> datalist = new ArrayList<Map<String,Object>>();
        for (SomeResult result : results) {
            Map map = new HashMap();
            map.put("field_a", result.field_a);
            map.put("field_b", result.field_b);
            datalist.add(map);
        }

        String[] from = {"field_a","field_b"};

        int[] to = {R.id.textview_a,R.id.textview_b};

        // get a reference to the ListView

        ListView lv = (ListView)findViewById(R.id.listview);

        lv.setBackgroundColor(0xffffffff);

        lv.setOnItemClickListener(itemclick_drawHours);

        SimpleAdapter adapter = new SimpleAdapter(this.getApplicationContext(), datalist, R.layout.list_item, from, to);
        lv.setAdapter(adapter);

        lv.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
        lv.setCacheColorHint(0xffffffff);
        viewFlipper.setDisplayedChild(2);

Using DDMS and MAT, I noticed that while the number of ListView objects does not increase, the number of TextViews, RelativeLayouts and ImageViews were increasing steadily along with the number of times a user has clicked and a new list has been drawn. Here are the object counts of these three widgets +ListView at various stages of app usage.

App Installed onto emulator:
  android.widget.TextView: 16
  android.widget.RelativeLayout: 9
  android.widget.ImageView: 8
  android.widget.ListView: 4

Light Use (a dozen or so clicks and ListViews drawn):
  android.widget.TextView: 107
  android.widget.RelativeLayout: 48
  android.widget.ImageView: 34
  android.widget.ListView: 4

Medium Use (a couple dozen clicks/ListViews drawn):
  // At this point, a lot of GC messages and Resizing JIT Table messages etc. in LogCat
  android.widget.TextView: 158
  android.widget.RelativeLayout: 72
  android.widget.ImageView: 61
  android.widget.ListView: 4

Heavy Use (three dozen or so clicks/ListViews drawn):
  // Even more messages in logcat
  android.widget.TextView: 222
  android.widget.RelativeLayout: 103
  android.widget.ImageView: 92
  android.widget.ListView: 4

The app does not actually crash while open, just gets less responsive and laggy. After a period of medium/heavy use, closing and opening the app causes an OutOfMemory Error when displaying an ImageView.

Here is list_item.xml ..

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
<TextView 
    android:id="@+id/textview_a"
    android:layout_width="wrap_content"
    android:layout_height="fill_parent"
    android:padding="10dp"
    android:textColor="#000000"
    android:layout_alignParentLeft="true"
    android:textSize="18dp" >
</TextView>
<ImageView 
    android:id="@+id/rightarrow" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_centerVertical="true" 
    android:layout_marginRight="5dip"
    android:src="@drawable/garrow"
    android:layout_alignParentRight="true"
/>
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content"
    android:text="" android:id="@+id/textview_b" android:visibility="gone" />
</RelativeLayout>

If you look at the 2(TextViews) to 1(ImageView) to 1(RelativeLayout) ratio in this template and in the object counts above, it seems that ImageViews, TextViews and RelativeLayouts created by SimpleAdapter are not being released properly.

Is there anything obvious that I'm missing? I've read some other posts where they say this problem only seems to occur in "debug" mode. I'm not sure how to turn this on/off except changing the android:debuggable="true" or "false" in the manifest.

Answer 1

List<Map<String,Object>> ?...List of Maps each of which keys on a string to an object ... 

What is result? sounds maybe like it keys on - time like time of event - then you are adding to a Collection keyed on a String literal -- need to read some more docs ..

list_item.xml initializes the program = it is not a coding context for the program

I am pretty new at Android but I have been writing Java well enough to see you need to populate the ListView from the Collection, which without details might be

TreeMap<Integer,SomeResult>Stuff=new TreeMap<Integer,SomeResult>();

to get the new item where the program can find it you put it in collection of your choice -- they have a sparse collection datatype somewhere in the work

I dont see where the leak is coming from but I bet it is from the R. as reading how that works makes that the likely candidate in my mind based on the way you are using it compared to how it works