android - Odd behavior in adding items to listview -
i have custom photo gallery , need selected images , display filenames in listview
this custom gallery:
import android.app.activity; import android.content.context; import android.content.intent; import android.database.cursor; import android.graphics.bitmap; import android.os.asynctask; import android.os.bundle; import android.provider.mediastore; import android.util.log; import android.view.layoutinflater; import android.view.view; import android.view.viewgroup; import android.widget.baseadapter; import android.widget.button; import android.widget.checkbox; import android.widget.gridview; import android.widget.imageview; import android.widget.toast; public class customphotogallery extends activity { private gridview grdimages; private button btnselect; private imageadapter imageadapter; private string[] arrpath; private boolean[] thumbnailsselection; private int ids[]; private int count; string filename; /** * overrides methods */ @override public void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.custom_gallery); grdimages= (gridview) findviewbyid(r.id.grdimages); btnselect= (button) findviewbyid(r.id.btnselect); final string[] columns = { mediastore.images.media.data, mediastore.images.media._id }; final string orderby = mediastore.images.media._id; @suppresswarnings("deprecation") cursor imagecursor = managedquery(mediastore.images.media.external_content_uri, columns, null, null, orderby); int image_column_index = imagecursor.getcolumnindex(mediastore.images.media._id); this.count = imagecursor.getcount(); this.arrpath = new string[this.count]; ids = new int[count]; this.thumbnailsselection = new boolean[this.count]; (int = 0; < this.count; i++) { imagecursor.movetoposition(i); ids[i] = imagecursor.getint(image_column_index); int datacolumnindex = imagecursor.getcolumnindex(mediastore.images.media.data); arrpath[i] = imagecursor.getstring(datacolumnindex); } imageadapter = new imageadapter(); grdimages.setadapter(imageadapter); imagecursor.close(); btnselect.setonclicklistener(new view.onclicklistener() { public void onclick(view v) { final int len = thumbnailsselection.length; int cnt = 0; string selectimages = ""; (int = 0; < len; i++) { if (thumbnailsselection[i]) { cnt++; selectimages = selectimages + arrpath[i] + "|"; } } if (cnt == 0) { toast.maketext(getapplicationcontext(), "please select @ least 1 image", toast.length_long).show(); } else { log.d("selectedimages", selectimages); intent = new intent(); i.putextra("data", selectimages); setresult(activity.result_ok, i); finish(); } } }); } @override public void onbackpressed() { setresult(activity.result_canceled); super.onbackpressed(); } /** * class method */ /** * method used set bitmap. * @param iv represented imageview * @param id represented id */ private void setbitmap(final imageview iv, final int id) { new asynctask<void, void, bitmap>() { @override protected bitmap doinbackground(void... params) { return mediastore.images.thumbnails.getthumbnail(getapplicationcontext().getcontentresolver(), id, mediastore.images.thumbnails.micro_kind, null); } @override protected void onpostexecute(bitmap result) { super.onpostexecute(result); iv.setimagebitmap(result); } }.execute(); } /** * list adapter * @author tasol */ public class imageadapter extends baseadapter { private layoutinflater minflater; public imageadapter() { minflater = (layoutinflater) getsystemservice(context.layout_inflater_service); } public int getcount() { return count; } public object getitem(int position) { return position; } public long getitemid(int position) { return position; } public view getview(int position, view convertview, viewgroup parent) { final viewholder holder; if (convertview == null) { holder = new viewholder(); convertview = minflater.inflate(r.layout.custom_gallery_item, null); holder.imgthumb = (imageview) convertview.findviewbyid(r.id.imgthumb); holder.chkimage = (checkbox) convertview.findviewbyid(r.id.chkimage); convertview.settag(holder); } else { holder = (viewholder) convertview.gettag(); } holder.chkimage.setid(position); holder.imgthumb.setid(position); holder.chkimage.setonclicklistener(new view.onclicklistener() { public void onclick(view v) { checkbox cb = (checkbox) v; int id = cb.getid(); if (thumbnailsselection[id]) { cb.setchecked(false); thumbnailsselection[id] = false; } else { cb.setchecked(true); thumbnailsselection[id] = true; } } }); holder.imgthumb.setonclicklistener(new view.onclicklistener() { public void onclick(view v) { int id = holder.chkimage.getid(); if (thumbnailsselection[id]) { holder.chkimage.setchecked(false); thumbnailsselection[id] = false; } else { holder.chkimage.setchecked(true); thumbnailsselection[id] = true; } } }); try { setbitmap(holder.imgthumb, ids[position]); } catch (throwable e) { } holder.chkimage.setchecked(thumbnailsselection[position]); holder.id = position; return convertview; } } /** * inner class * @author tasol */ class viewholder { imageview imgthumb; checkbox chkimage; int id; } } now result based on selection goes main activity need display selected images in listview.
this i'm trying do
@override public void onactivityresult(int requestcode, int resultcode, intent data) { super.onactivityresult(requestcode, resultcode, data); if (resultcode == result_ok) { if(requestcode == pick_image_multiple){ imagespathlist = new arraylist<string>(); string[] imagespath = data.getstringextra("data").split("\\|"); try{ lnrimages.removeallviews(); }catch (throwable e){ e.printstacktrace(); } (int i=0;i<imagespath.length;i++){ //toast.maketext(mainactivity.this,string.valueof(imagespath.length),toast.length_long).show(); imagespathlist.add(imagespath[i]); //toast.maketext(mainactivity.this,imagespathlist.tostring(),toast.length_long).show(); yourbitmap = bitmapfactory.decodefile(imagespath[i]); imageview imageview = new imageview(this); imageview.setimagebitmap(yourbitmap); imageview.setadjustviewbounds(true); //lnrimages.addview(imageview); uri uri = (uri.fromfile(new file(imagespath[i]))); filename = uri.getlastpathsegment(); //toast.maketext(mainactivity.this,filename,toast.length_long).show(); uri selectedimage = data.getdata(); encodedimage= bitmaptobase64(yourbitmap); //toast.maketext(mainactivity.this,encodedimage,toast.length_long).show(); mystringlist.add(filename); mystringarray = mystringlist.toarray(); lv.setadapter(null); toast.maketext(mainactivity.this,(string)mystringarray[i],toast.length_long).show(); arrayadapter = new arrayadapter<string>( this, android.r.layout.simple_list_item_1, mystringlist ); lv.setadapter(arrayadapter); arrayadapter.notifydatasetchanged(); } } } } now problem is:
1) if select 1 single image it's showing me toast filename not adding listview
2)if select 2 images adding list view normal
3) if select more 2 appending old list(ie..adding newly selected images selected images) though have set adapter 'null'
4) selecting large number of images takes time consumption adding listview crashing app due memory.
so can suggest me best way of handling ?
thanks in advance!
there multiple problems in code. in java reference, instead of creating adapter again , again, should set new list adapter , should call notifydatasetchanged. example, imageadapter should this
public class imageadapter extends baseadapter { private layoutinflater minflater; private arraylist<string> imageslist = new arraylist<>(); public void updateimageslist(arraylist<strinf> newimages) { if(newimages != null && newimages.size() > 0) { this.imageslist.clear(); this.imageslist.addall(newimages); } } } and should create global adapter variable using future list updates
and in onactivityresult, should populate strings list in loop , after loop should update adapter list as
@override public void onactivityresult(int requestcode, int resultcode, intent data) { super.onactivityresult(requestcode, resultcode, data); if (resultcode == result_ok) { if (requestcode == pick_image_multiple) { (int = 0; < imagespath.length; i++) { //toast.maketext(mainactivity.this,string.valueof(imagespath.length),toast.length_long).show(); imagespathlist.add(imagespath[i]); //toast.maketext(mainactivity.this,imagespathlist.tostring(),toast.length_long).show(); yourbitmap = bitmapfactory.decodefile(imagespath[i]); imageview imageview = new imageview(this); imageview.setimagebitmap(yourbitmap); imageview.setadjustviewbounds(true); //lnrimages.addview(imageview); uri uri = (uri.fromfile(new file(imagespath[i]))); filename = uri.getlastpathsegment(); //toast.maketext(mainactivity.this,filename,toast.length_long).show(); uri selectedimage = data.getdata(); encodedimage = bitmaptobase64(yourbitmap); //toast.maketext(mainactivity.this,encodedimage,toast.length_long).show(); mystringlist.add(filename); toast.maketext(mainactivity.this, (string) mystringarray[i], toast.length_long).show(); } arrayadapter.updateimages(mystringlist); arrayadapter.notifydatasetchanged(); } } } apart above 2 changes, there great performance impact because you doing i/o operations on ui thread decoding bitmap files on main thread not approach cause outofmemoryerror it slow down application. should bitmap operations or displaying using universal image loader https://github.com/nostra13/android-universal-image-loader
hope helps.
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