er...
On 6月30日, 下午10时40分, Streets Of Boston <flyingdutc...@gmail.com> wrote:
> Your code in your getView implementation of the adapter looks good at
> first sight. The structure of this method looks good.
>
> I think there are a few issues though.
>
> In your getView(...) method, you access the variable 'appList':
>
> if (position >= appList.size()) {
> return null;
> }
>
> and
>
> ObjectToShow objectToShow = appList.get
> (position);
> ObjectToShow objectToShowWithMetadata =
> appMap.get
>
> The only place i can find a declared variable called 'appList' in your
> example code is the one that is a private member of IconLoaderThread:
>
> class IconLoaderThread extends Thread {
> List<ObjectToShow> appList;
> ...
> }
>
> In short, this 'appList' is accessed in two threads without any
> synchronization or attempt to make it immutable.
>
> Also, the plain assignment here worries me:
> public EfficientAdapter(Context c, List<ObjectToShow>
> appList) {
> if (appList != null) {
> // Just refresh the list
> --> appLocalList = appList; <---
> ...
> }
> ...
> }
>
> because in the method 'initList' you do something similar, but you
> assign a copy of appList to appLocalList.
>
> On Jun 30, 12:43 am, Peter <pkana...@gmail.com> wrote:
>
> > Doug, you were right.
>
> > If I inflate a new view each time instead of using the cached
> > convertView, the images never show incorrectly. This is obviously less
> > efficient, but it's right. I need to look more closely to see if I was
> > abusing the ViewHolder pattern, but I don't see how I was.
>
> > This is what I'm doing now in convertView():
>
> > public View getView(int position, View convertView, ViewGroup
> > parent)
> > {
> > if (position >= appList.size()) {
> > return null;
> > }
> > convertView = mInflater.inflate
> > (R.layout.app_list_item, null);
>
> > ObjectToShow objectToShow = appList.get
> > (position);
> > ObjectToShow objectToShowWithMetadata =
> > appMap.get
> > (objectToShow.getKey());
> > if(objectToShow != null) {
> > if(objectToShowWithMetadata.getName() !
> > = null) {
> > ((TextView)
> > convertView.findViewById(R.id.app_list_item_name)).setText
> > (objectToShowWithMetadata.getName());
> > }
> > if(iconMap.get(objectToShow.getKey()) !
> > = null) {
> > ((ImageView)
> > convertView.findViewByI(R.id.app_list_item_icon)).setImageBitmap
> > (iconMap.get(objectToShow.getKey()));
> > }
> > } else {
> > ((TextView)convertView.findViewById
> > (R.id.app_list_item_name)).setText(defaultText);
> > ((ImageView)convertView.findViewByI
> > (R.id.app_list_item_icon)).setImageDrawable(defaultIcon);
> > }
> > return convertView;
> > }
>
> > Any thoughts?
>
> > On Jun 27, 4:17 pm, Doug <dougforp...@gmail.com> wrote:
>
> > > Have you tried *not* caching the component views in your ViewHolder
> > > object - instead looking them up whenever you get a redraw request?
> > > You may find that the list is re-using objects, and your image issue
> > > is simply an artifact of that.
>
> > > Doug
>
> > > On Jun 26, 10:56 pm, Peter <pkana...@gmail.com> wrote:
>
> > > > > There's not adefaultnumberof views created for an adapter. A list
> > > > > creates as many views as it needs to fill the screen. Views get reused
> > > > > only when you start scrolling or when the adapter send a
> > > > > notifyDatasetChanged(). You say you have a thread updating the data,
> > > > > what is exactly that thread doing? Please show code.
>
> > > > Here is some code. Perhaps it will help.
>
> > > > ********** the worker thread ***************
> > > > --------------------------------------
>
> > > > class IconLoaderThread extends Thread {
> > > > List<ObjectToShow> appList;
> > > > void loadAllResources(List<ObjectToShow> appList) {
> > > > this.appList = appList;
> > > > start();
> > > > }
>
> > > > public void run() {
> > > > int maxSize;
>
> > > > for (int i = 0; i < maxSize; i++) {
> > > > ObjectToShow appInfo = appList.get(i);
> > > > // network access occurs here
> > > > Bitmap icon =
> > > > appQuery.lookupAppIcon(appInfo);
> > > > Message msg =
> > > > handler.obtainMessage(MSG_REFRESH_APP_ICON);
> > > > Bundle data = new Bundle();
> > > > data.putString("s3ObjectKey",
> > > > appInfo.getS3ObjectKey());
> > > > msg.obj = icon;
> > > > msg.setData(data);
> > > > handler.sendMessage(msg);
> > > > }
> > > > Message doneMsg =
> > > > handler.obtainMessage(MSG_ICONS_DONE);
> > > > handler.sendMessage(doneMsg);
> > > > }
> > > > }
>
> > > > ********** the handler ***************
> > > > --------------------------------------
>
> > > > private Handler handler = new Handler() {
> > > > public void handleMessage(Message msg) {
> > > > ObjectToShow appInfo;
> > > > switch (msg.what) {
> > > > case MSG_INIT_APP_LIST:
> > > > initProgressBar();
> > > >
> > > > handler.sendEmptyMessage(MSG_NEXT_LOAD_STEP);
> > > > break;
> > > > case MSG_REFRESH_APP_ICON:
> > > > Bitmap icon = (Bitmap)msg.obj;
> > > > String s3ObjectKey =
> > > > msg.getData().getString("s3ObjectKey");
> > > > if(icon == null || s3ObjectKey == null)
> > > > {
> > > > Log.w(TAG, "Error loading
> > > > icon");
> > > > } else {
> > > >
> > > > efficientAdapter.updateAppInfoIcon(s3ObjectKey, icon);
> > > > }
> > > > break;
> > > > case MSG_REFRESH_APP_METADATA:
> > > > appInfo = (ObjectToShow)msg.obj;
> > > > if(appInfo == null) {
> > > > Log.w(TAG, "Error loading
> > > > icon");
> > > > } else {
> > > >
> > > > efficientAdapter.updateAppInfoMetadata(appInfo);
> > > > }
> > > > break;
> > > > case MSG_METADATA_DONE:
> > > > metadataLoaded = true;
> > > >
> > > > handler.sendEmptyMessage(MSG_NEXT_LOAD_STEP);
> > > > break;
> > > > case MSG_ICONS_DONE:
> > > > iconsLoaded = true;
> > > >
> > > > handler.sendEmptyMessage(MSG_NEXT_LOAD_STEP);
> > > > break;
> > > > case MSG_NEXT_LOAD_STEP:
> > > > if (metadataLoaded && iconsLoaded) {
> > > > doneLoadingMetadata();
> > > > }
> > > > else if (metadataLoaded || iconsLoaded)
> > > > {
> > > > if (firstRun) {
> > > > // Set the adapter here.
> > > > firstRun = false;
> > > >
> > > > appListView.setAdapter(efficientAdapter);
> > > > dismissLoadingMessage();
> > > > }
> > > > initIconThread();
>
> ...
>
> 阅读更多 >>
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