Bild Thumbnails nicht richtig eingestellt

Question

Ich versuche, einen Datei-Explorer zu machen. Ich habe alles erreicht, außer dass meine Bildminiaturen zu langsam geladen wurden. Also lese ich, dass ich zu asynctask wechseln muss und dann in post execute die ui aktualisiere. Vor dem Ausführen von asynctask stelle ich allen meinen Dateien eine Standard-Miniaturansicht zur Verfügung. In asynctask nehme ich Position als Parameter, da ich Tags mit ihnen setze. Dann überprüfe ich die Datei anhand dieser Position. Wenn das Bild oder Video ist, erstelle ich eine Bitmap dafür. In post execute erstelle ich einen neuen Viewholder und weise ihm mit getTag (position) das gleiche Tag zu. Dann weise ich die Bitmap mit setBitmapImage zu. Problem: Thumbnails ändern sich/blinken sogar für die Dateien, die keine Bilder/Videos sind. Dinge, die ich versucht habe bisher: a) updating of Image Thumbnails using AsyncTask for Android ListView not coming proper
b) Android ListView updating of Image Thumbnails using AsyncTask Causes View recycling

hier ist mein Code für getView:

@Override 
public View getView(final int position, View convertView, ViewGroup parent) { 


    File file=new File(String.valueOf(filenames[position])); 
    if(file.isDirectory()){ 
     img=R.drawable.folder; 
    } 

    else{ 
     img=getImage(filenames[position]); 
    } 

    ViewHolder viewHolder = null; 
    if (convertView == null) { 
     LayoutInflater inflator = LayoutInflater.from(getContext()); 
     convertView = inflator.inflate(R.layout.list_item, null); 
     viewHolder = new ViewHolder(); 
     viewHolder.tv = (TextView) convertView.findViewById(R.id.textView1); 
     viewHolder.cb = (CheckBox) convertView.findViewById(R.id.checkBox1); 
     viewHolder.iv= (ImageView)convertView.findViewById(R.id.imageView); 
     viewHolder.cb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { 

      @Override 
      public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { 
       int getPosition = (Integer) buttonView.getTag(); // Here we get the position that we have set for the checkbox using setTag. 
       myList.get(getPosition).setSelected(buttonView.isChecked()); // Set the value of checkbox to maintain its state. 
      } 
     }); 
     convertView.setTag(viewHolder); 
     convertView.setTag(R.id.textView1, viewHolder.tv); 
     convertView.setTag(R.id.checkBox1, viewHolder.cb); 
     convertView.setTag(R.id.checkBox1, viewHolder.iv); 
    } 
    else { 
     viewHolder = (ViewHolder) convertView.getTag(); 
    } 
    viewHolder.iv.getLayoutParams().height = 80; 
    viewHolder.iv.getLayoutParams().width = 80; 
    viewHolder.cb.setTag(position); 
    final ViewHolder ViewHolder= viewHolder; 
    ViewHolder.iv.setImageResource(img); 
    ViewHolder.tv.setText(myList.get(position).getName()); 
    ViewHolder.cb.setChecked(myList.get(position).isSelected()); 


    final View finalConvertView = convertView; 
    class myTask extends AsyncTask<Integer,Void,Bitmap>{ 

     int pos; 
     public myTask(int pos){ 
      this.pos=pos; 
     } 

     @Override 
     protected Bitmap doInBackground(Integer... params) { 
      Bitmap thumb=null; 

      if((String.valueOf(filenames[pos])).contains(".jpeg")||String.valueOf(filenames[pos]).contains(".jpg")||String.valueOf(filenames[pos]).contains(".png")||String.valueOf(filenames[pos]).contains(".bmp")||String.valueOf(filenames[pos]).contains(".webp")||String.valueOf(filenames[pos]).contains(".gif")){ 
       thumb = ThumbnailUtils.extractThumbnail(BitmapFactory.decodeFile(String.valueOf(filenames[pos])), 64, 64); 

      } 
      else if((String.valueOf(filenames[pos])).contains(".mp4")||String.valueOf(filenames[pos]).contains(".mkv")||String.valueOf(filenames[pos]).contains(".webm")||String.valueOf(filenames[pos]).contains(".3gp")||String.valueOf(filenames[pos]).contains(".3gpp")){ 
       thumb=ThumbnailUtils.createVideoThumbnail(filenames[pos].getPath(), MediaStore.Video.Thumbnails.MINI_KIND); 

      } 
      return thumb; 
     } 
     @Override 
     protected void onPostExecute(Bitmap thumb){ 
      if(isCancelled()){ 
       return; 
      } 
      ViewHolder v= (ViewHolder) finalConvertView.getTag(pos); 

      if((String.valueOf(filenames[pos])).contains(".jpeg")||String.valueOf(filenames[pos]).contains(".jpg")||String.valueOf(filenames[pos]).contains(".png")||String.valueOf(filenames[pos]).contains(".bmp")||String.valueOf(filenames[pos]).contains(".webp")||String.valueOf(filenames[pos]).contains(".gif")){ 

       v.iv.setImageBitmap(thumb); 
      } 
      else if((String.valueOf(filenames[pos])).contains(".mp4")||String.valueOf(filenames[pos]).contains(".mkv")||String.valueOf(filenames[pos]).contains(".webm")||String.valueOf(filenames[pos]).contains(".3gp")||String.valueOf(filenames[pos]).contains(".3gpp")){ 

       v.iv.setImageBitmap(thumb); 
      } 


     } 
    } 

    myTask m=new myTask(position); 
    m.execute(); 

    return convertView; 



} 

Answer 1

ich endlich Antwort auf diese Frage gefunden zu haben. Hier

ist die ListAdapter Klasse:

class ListAdapter extends ArrayAdapter<Modal> { 

    private final Context context; 
    private int img; 

    private List<Modal> myList; 
    private File filenames[]; 
    private List<Integer> selectedItems=new ArrayList<Integer>(); 
    private CheckBox cb; 
    public ListAdapter(Context context, List<Modal> list, File filenames[]) { 
     super(context, R.layout.list_item, list); 
     this.context = context; 
     this.myList = list; 
     this.filenames=filenames; 
    } 


    @Override 
    public int getViewTypeCount() { 

     if(getCount()>0){ 
      return getCount(); 
     } 
     return 1; 
    } 

    @Override 
    public int getItemViewType(int position) { 

     return position; 
    } 

    @Override 
    public long getItemId(int position) { 
     return position; 
    } 


    static class ViewHolder { 
     TextView tv; 
     CheckBox cb; 
     static ImageView iv; 
    } 

    public int getImage(File filename){ 
     if(String.valueOf(filename).contains(".rar")||String.valueOf(filename).contains(".zip")){ 
      return R.drawable.archive; 
     } 
     else if(String.valueOf(filename).contains(".doc")||String.valueOf(filename).contains(".docx")){ 
      return R.drawable.doc; 
     } 
     else if(String.valueOf(filename).contains(".pdf")){ 
      return R.drawable.pdf; 
     } 
     else if(String.valueOf(filename).contains(".txt")){ 
      return R.drawable.txt; 
     } 
     else if(String.valueOf(filename).contains(".ppt")||String.valueOf(filename).contains(".pptx")){ 
      return R.drawable.ppt; 
     } 
     else if(String.valueOf(filename).contains(".xls")||String.valueOf(filename).contains(".xlsx")){ 
      return R.drawable.xls; 
     } 
     else if((String.valueOf(filename).contains(".jpeg")||String.valueOf(filename).contains(".jpg")||String.valueOf(filename).contains(".png")||String.valueOf(filename).contains(".bmp")||String.valueOf(filename).contains(".webp")||String.valueOf(filename).contains(".gif"))){ 
      return R.drawable.image; 
     } 
     else if((String.valueOf(filename).contains(".mp4")||String.valueOf(filename).contains(".mkv")||String.valueOf(filename).contains(".webm")||String.valueOf(filename).contains(".3gp")||String.valueOf(filename).contains(".3gpp"))||String.valueOf(filename).contains(".MOV")){ 
      return R.drawable.video; 
     } 
     else if((String.valueOf(filename).contains(".mp3")||String.valueOf(filename).contains(".wav")||String.valueOf(filename).contains(".wma")||String.valueOf(filename).contains(".MP2")||String.valueOf(filename).contains(".AAC")||String.valueOf(filename).contains(".AC3")||String.valueOf(filename).contains(".AU")||String.valueOf(filename).contains(".OGG")||String.valueOf(filename).contains(".FLAC"))){ 
      return R.drawable.music; 
     } 

     else { 
      return R.drawable.unknown; 
     } 

    } 


    @Override 
    public View getView(final int position, View convertView, ViewGroup parent) { 




     File file=new File(String.valueOf(filenames[position])); 
     if(file.isDirectory()){ 
      img=R.drawable.folder; 
     } 

     else{ 
      img=getImage(filenames[position]); 
     } 


     ViewHolder viewHolder = null; 

     if (convertView == null) { 
      LayoutInflater inflator = LayoutInflater.from(getContext()); 
      convertView = inflator.inflate(R.layout.list_item, null); 
      viewHolder = new ViewHolder(); 
      viewHolder.tv = (TextView) convertView.findViewById(R.id.textView1); 
      viewHolder.cb = (CheckBox) convertView.findViewById(R.id.checkBox1); 
      viewHolder.iv= (ImageView)convertView.findViewById(imageView); 
      viewHolder.cb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { 

       @Override 
       public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { 
        int getPosition = (Integer) buttonView.getTag(); // Here we get the position that we have set for the checkbox using setTag. 
        myList.get(getPosition).setSelected(buttonView.isChecked()); // Set the value of checkbox to maintain its state. 
       } 
      }); 
      convertView.setTag(viewHolder); 
      convertView.setTag(R.id.textView1, viewHolder.tv); 
      convertView.setTag(R.id.checkBox1, viewHolder.cb); 
      convertView.setTag(R.id.checkBox1, viewHolder.iv); 
     } 
     else { 
      viewHolder = (ViewHolder) convertView.getTag(); 
     } 

     viewHolder.iv.getLayoutParams().height = 150; 
     viewHolder.iv.getLayoutParams().width = 150; 
     viewHolder.cb.setTag(position); 
     final ViewHolder ViewHolder= viewHolder; 

     ViewHolder.tv.setText(myList.get(position).getName()); 
     ViewHolder.cb.setChecked(myList.get(position).isSelected()); 
     viewHolder.iv.setImageResource(img); 


     Log.v("this","viewHolderMT: "+String.valueOf(viewHolder)+" position: "+position); 
     myTask m=new myTask(position,viewHolder.iv); 
     m.execute(); 

     return convertView; 



    } 
    class myTask extends AsyncTask<Integer,Bitmap,Bitmap>{ 



     int pos; 
     ImageView iv; 
     public myTask(int pos,ImageView iv){ 
      this.pos=pos; 
      this.iv=iv; 
      iv.setTag(pos); 


     } 

     @Override 
     protected Bitmap doInBackground(Integer... params) { 
      Bitmap thumb=null; 


      if((String.valueOf(filenames[pos])).contains(".jpeg")||String.valueOf(filenames[pos]).contains(".jpg")||String.valueOf(filenames[pos]).contains(".png")||String.valueOf(filenames[pos]).contains(".bmp")||String.valueOf(filenames[pos]).contains(".webp")||String.valueOf(filenames[pos]).contains(".gif")){ 

       thumb = ThumbnailUtils.extractThumbnail(BitmapFactory.decodeFile(String.valueOf(filenames[pos])), 150, 150); 

      } 
      else if((String.valueOf(filenames[pos])).contains(".mp4")||String.valueOf(filenames[pos]).contains(".mkv")||String.valueOf(filenames[pos]).contains(".webm")||String.valueOf(filenames[pos]).contains(".3gp")||String.valueOf(filenames[pos]).contains(".3gpp")||String.valueOf(filenames[pos]).contains(".MOV")){ 
       thumb=ThumbnailUtils.createVideoThumbnail(filenames[pos].getPath(), MediaStore.Video.Thumbnails.MINI_KIND); 


      } 
      return thumb; 
     } 
     @Override 
     protected void onProgressUpdate(Bitmap... thumb){ 


     } 
     @Override 
     protected void onPostExecute(Bitmap thumb){ 


      if(thumb!=null && (Integer)iv.getTag()==this.pos) { 
       if ((String.valueOf(filenames[pos])).contains(".jpeg") || String.valueOf(filenames[pos]).contains(".jpg") || String.valueOf(filenames[pos]).contains(".png") || String.valueOf(filenames[pos]).contains(".bmp") || String.valueOf(filenames[pos]).contains(".webp") || String.valueOf(filenames[pos]).contains(".gif")) { 

        iv.setImageBitmap(thumb); 

       } 
       else if ((String.valueOf(filenames[pos])).contains(".mp4") ||String.valueOf(filenames[pos]).contains(".MOV")|| String.valueOf(filenames[pos]).contains(".mkv") || String.valueOf(filenames[pos]).contains(".webm") || String.valueOf(filenames[pos]).contains(".3gp") || String.valueOf(filenames[pos]).contains(".3gpp")) { 

        iv.setImageBitmap(thumb); 
       } 


      } 





     } 
    } 
} 

Fehler, die ich mache:

• Verschieben AsyncTask außerhalb GetView()
• Geben Sie einen Verweis auf die Imageview innerhalb der Asynchron-Konstruktor
• Implementieren Sie auch die Funktionen getItemViewType() und getItemId()
• War nicht c Markieren des Positions-Tags in onPostExecute, sodass die Bilder gemischt wurden.

Dies dauerte eine Weile für mich herauszufinden. Hoffe es hilft anderen!