问题
Hello Stack Overflow Android Users,
Please help with the following question:
Problem
I'm writing an a feature for an app that lists species of fish. I'm using a custom ListView Adapter class (let's call this FishSpeciesListAdapter) for the adapter. I have 27 fish species recorded as a default for the program as for now (you will eventually be able to add some yourself as well). The problem is that when I link the adapter to the actual listview xml object and scroll down the list, after a while, I get the following error:
UNHANDLED EXCEPTION: Java.Lang.OutOfMemoryError: Exception of type 'Java.Lang.OutOfMemoryError' was thrown.
at Android.Runtime.JNIEnv.CallStaticObjectMethod (intptr,intptr,Android.Runtime.JValue[]) <0x00080>
at Android.Graphics.BitmapFactory.DecodeByteArray (byte[],int,int) <0x001db>
at FishinTales.FishSpeciesListAdapter.GetView (int,Android.Views.View,Android.Views.ViewGroup) <0x002f7>
at Android.Widget.BaseAdapter.n_GetView_ILandroid_view_View_Landroid_view_ViewGroup_ (intptr,intptr,int,intptr,intptr) <0x00093>
at (wrapper dynamic-method) object.5dcc133f-a229-41c4-80e2-f5f5260ecdad (intptr,intptr,int,intptr,intptr) <0x0004b>
--- End of managed exception stack trace ---
java.lang.OutOfMemoryError: bitmap size exceeds VM budget
at android.graphics.BitmapFactory.nativeDecodeByteArray(Native Method)
at android.graphics.BitmapFactory.decodeByteArray(BitmapFactory.java:392)
at android.graphics.BitmapFactory.decodeByteArray(BitmapFactory.java:405)
at fishintales.FishSpeciesListAdapter.n_getView(Native Method)
at fishintales.FishSpeciesListAdapter.getView(FishSpeciesListAdapter.java:55)
at android.widget.AbsListView.obtainView(AbsListView.java:1294)
at android.widget.ListView.addViewBelow(ListView.java:2896)
at android.widget.ListView.scrollListItemsBy(ListView.java:2825)
at android.widget.ListView.arrowScrollImpl(ListView.java:2322)
at android.widget.ListView.arrowScroll(ListView.java:2269)
at android.widget.ListView.commonKey(ListView.java:2071)
at android.widget.ListView.onKeyDown(ListView.java:2018)
at android.view.KeyEvent.dispatch(KeyEvent.java:1037)
at android.view.View.dispatchKeyEvent(View.java:3740)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:786)
at android.widget.ListView.dispatchKeyEvent(ListView.java:2003)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1667)
at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1102)
at android.app.Activity.dispatchKeyEvent(Activity.java:2063)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1643)
at android.view.ViewRoot.deliverKeyEventToViewHierarchy(ViewRoot.java:2471)
at android.view.ViewRoot.handleFinishedEvent(ViewRoot.java:2441)
at android.view.ViewRoot.handleMessage(ViewRoot.java:1735)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4627)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
at dalvik.system.NativeStart.main(Native Method)
Unhandled Exception:
Java.Lang.OutOfMemoryError: Exception of type 'Java.Lang.OutOfMemoryError' was thrown.
at Android.Runtime.JNIEnv.CallStaticObjectMethod (intptr,intptr,Android.Runtime.JValue[]) <0x00080>
at Android.Graphics.BitmapFactory.DecodeByteArray (byte[],int,int) <0x001db>
at FishinTales.FishSpeciesListAdapter.GetView (int,Android.Views.View,Android.Views.ViewGroup) <0x002f7>
at Android.Widget.BaseAdapter.n_GetView_ILandroid_view_View_Landroid_view_ViewGroup_ (intptr,intptr,int,intptr,intptr) <0x00093>
at (wrapper dynamic-method) object.5dcc133f-a229-41c4-80e2-f5f5260ecdad (intptr,intptr,int,intptr,intptr) <0x0004b>
--- End of managed exception stack trace ---
java.lang.OutOfMemoryError: bitmap size exceeds VM budget
at android.graphics.BitmapFactory.nativeDecodeByteArray(Native Method)
at android.graphics.BitmapFactory.decodeByteArray(BitmapFactory.java:392)
at android.graphics.BitmapFactory.decodeByteArray(BitmapFactory.java:405)
at fishintales.FishSpeciesListAdapter.n_getView(Native Met
Here's my Custom ListAdapter:
public class FishSpeciesListAdapter : BaseAdapter
{
Context n_context;
List<AppCode.Specie> n_specieData;
public FishSpeciesListAdapter (Context context, List<AppCode.Specie> specieData)
{
this.n_context = context;
this.n_specieData = specieData;
}
public override int Count {
get { return this.n_specieData.Count; }
}
public override Java.Lang.Object GetItem (int position)
{
return null;
}
public override long GetItemId (int position)
{
return 0;
}
// create a new ImageView for each item referenced by the Adapter
public override View GetView (int position, View convertView, ViewGroup parent)
{
View v;
if(convertView==null){
LayoutInflater li = LayoutInflater.FromContext(parent.Context);
v = li.Inflate(Resource.Layout.Adapter_FishSpeciesIcon, null);
}
else
{
v = convertView;
}
ImageView iconImage = (ImageView)convertView.FindViewById(Resource.Id.xml_adapter_fishSpeciesIconImage);
TextView nameText = (TextView)convertView.FindViewById(Resource.Id.xml_adapter_fishSpeciesNameText);
TextView scientificNameText = (TextView)convertView.FindViewById(Resource.Id.xml_adapter_fishSpeciesScientificNameText);
nameText.Text = this.n_specieData[position].Name;
scientificNameText.Text = this.n_specieData[position].ScientificName;
if (this.n_specieData[position].RelatedMedia.AttachedPhotos.Count < 1)
{
iconImage.SetImageResource(Resource.Drawable.Icon);
}
else
{
iconImage.SetImageBitmap(BitmapFactory.DecodeByteArray(this.n_specieData[position].RelatedMedia.AttachedPhotos[0], 0, this.n_specieData[position].RelatedMedia.AttachedPhotos[0].Length));
}
return v;
}
}
Other Research On My Behalf
All images are in the range of 100-300KB. Will this really cause this problem?
Please reference my last post for additional code as it is kind of related but needs a new question. Thanks for your time and help.
回答1:
Solved it!
What it was doing was getting held up on decoding byte arrays into Bitmaps everytime GetView was being called. So what I did was convert them all in the constructor and made a cache of Bitmaps to reference when the GetView method was called.
Here is my updated Custom ListView Adapter that works.
public class FishSpeciesListAdapter : BaseAdapter
{
Context n_context;
List<AppCode.Specie> n_specieData;
List<Bitmap> n_bitmapCache;
public FishSpeciesListAdapter (Context context, List<AppCode.Specie> specieData)
{
this.n_context = context;
this.n_specieData = specieData;
this.n_bitmapCache = new List<Bitmap>();
this.LoadBitmapsIntoCache();
}
private void LoadBitmapsIntoCache()
{
foreach(AppCode.Specie specie in this.n_specieData)
{
if (specie.RelatedMedia.AttachedPhotos.Count < 1)
{
this.n_bitmapCache.Add(BitmapFactory.DecodeResource(this.n_context.Resources, Resource.Drawable.Icon));
}
else
{
this.n_bitmapCache.Add(BitmapFactory.DecodeByteArray(specie.RelatedMedia.AttachedPhotos[0], 0, specie.RelatedMedia.AttachedPhotos[0].Length));
}
}
}
public override int Count {
get { return this.n_specieData.Count; }
}
public override Java.Lang.Object GetItem (int position)
{
return null;
}
public override long GetItemId (int position)
{
return 0;
}
// create a new ImageView for each item referenced by the Adapter
public override View GetView (int position, View convertView, ViewGroup parent)
{
if(convertView==null){
LayoutInflater li = LayoutInflater.FromContext(parent.Context);
convertView = li.Inflate(Resource.Layout.Adapter_FishSpeciesIcon, null);
}
ImageView iconImage = (ImageView)convertView.FindViewById(Resource.Id.xml_adapter_fishSpeciesIconImage);
TextView nameText = (TextView)convertView.FindViewById(Resource.Id.xml_adapter_fishSpeciesNameText);
TextView scientificNameText = (TextView)convertView.FindViewById(Resource.Id.xml_adapter_fishSpeciesScientificNameText);
nameText.Text = this.n_specieData[position].Name;
scientificNameText.Text = this.n_specieData[position].ScientificName;
iconImage.SetImageBitmap(this.n_bitmapCache[position]);
return convertView;
}
}
After calling LoadBitmapsIntoCache() in the constructor and saving the Bitmaps to a list. The problem was resolved and I could scroll through all the fish species without any OutOfMemory Errors. Thanks to all who helped.
来源：https://stackoverflow.com/questions/13685275/outofmemory-error-in-custom-listview-adapter-mono-android