如何将位图图像添加到ListAdapter？

Question

My adapter

ListAdapter adapter = new SimpleAdapter(this, contactList,
    R.layout.news_list_adapter,new String[] {TAG_NAME,  TAG_ADDRESS, R.drawable.news_en2},
    new int[] {R.id.newsHead,  R.id.qisaIzzah ,R.id.newsFontImage});

I have bitmap images that i want to add to the list, what can i write instead of R.drawable.news_en2

example bitmap

byte[] decodedString = Base64.decode(news.getString("newsimage"),Base64.DEFAULT);
Bitmap decodedByte = BitmapFactory.decodeByteArray(decodedString,0,decodedString.length); 

Answer 1

By extending BaseAdapter class you can easily add bitmap image in your ListView

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

        View row = convertView;
     // if it's not recycled, initialize some attributes
        if (row == null) {  
            LayoutInflater li = (LayoutInflater)   mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
            row = li.inflate(R.layout.menucategory, null);          
            //imageView.setLayoutParams(new GridView.LayoutParams(85, 85));         
        }
            // getCategoryItem          
            Category  category = (Category) getItem(position);
            // Get reference to ImageView
            categoryIcon = (ImageView) row.findViewById(R.id.category_image);
            //categoryIcon.setLayoutParams(new GridView.LayoutParams(85, 85));
            categoryIcon.setScaleType(ImageView.ScaleType.CENTER_CROP);
            categoryIcon.setPadding(5, 5, 5, 5);

            categoryName = (TextView) row.findViewById(R.id.category_name);
            //Set category name
            categoryName.setText(category.getCategoryName());           


            if(category.getCategoryPath() != null){             
                    Bitmap bitmap = BitmapFactory.decodeFile(category.getCategoryPath());
                    System.out.println("bitmap2::  "+ bitmap);
                    if(bitmap != null){
                     categoryIcon.setImageBitmap(bitmap);
                    }               
            }                              

        return row;
    }

Answer 2

You will also have to define a layout which can take the bitmap. In the above example posted by Mohammod Hossain, R.layout.menucategory refers to that custom layout.

Answer 3

Basically the simple adapter automatically bind some ressource id or URI to the imageview of your row layout. But it don't support Bitmap.

That's a problem, because everyone who had to manage bitmap know that we often have to reduce the size of the picture to prevent outOfMemory exceptions. But if you want to add images into a listView, you cannot reduce the image's size if you only provide URI. So here is the solution :

I have modified the simpleAdapter to be able to handle bitmap. Add this class into your project, and use it instead of simpleAdapter. Then instead of passing an URI or a ressourceId for an image, pass a Bitmap !

Hereunder is the code :

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.content.Context;
import android.graphics.Bitmap;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Checkable;
import android.widget.ImageView;
import android.widget.SimpleAdapter;
import android.widget.TextView;



public class ExtendedSimpleAdapter extends SimpleAdapter{
    List<HashMap<String, Object>> map;
    String[] from;
    int layout;
    int[] to;
    Context context;
    LayoutInflater mInflater;
    public ExtendedSimpleAdapter(Context context, List<HashMap<String, Object>> data,
            int resource, String[] from, int[] to) {
        super(context, data, resource, from, to);
        layout = resource;
        map = data;
        this.from = from;
        this.to = to;
        this.context = context;
    }


@Override
public View getView(int position, View convertView, ViewGroup parent) {
    mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    return this.createViewFromResource(position, convertView, parent, layout);
}

private View createViewFromResource(int position, View convertView,
        ViewGroup parent, int resource) {
    View v;
    if (convertView == null) {
        v = mInflater.inflate(resource, parent, false);
    } else {
        v = convertView;
    }

    this.bindView(position, v);

    return v;
}


private void bindView(int position, View view) {
    final Map dataSet = map.get(position);
    if (dataSet == null) {
        return;
    }

    final ViewBinder binder = super.getViewBinder();
    final int count = to.length;

    for (int i = 0; i < count; i++) {
        final View v = view.findViewById(to[i]);
        if (v != null) {
            final Object data = dataSet.get(from[i]);
            String text = data == null ? "" : data.toString();
            if (text == null) {
                text = "";
            }

            boolean bound = false;
            if (binder != null) {
                bound = binder.setViewValue(v, data, text);
            }

            if (!bound) {
                if (v instanceof Checkable) {
                    if (data instanceof Boolean) {
                        ((Checkable) v).setChecked((Boolean) data);
                    } else if (v instanceof TextView) {
                        // Note: keep the instanceof TextView check at the bottom of these
                        // ifs since a lot of views are TextViews (e.g. CheckBoxes).
                        setViewText((TextView) v, text);
                    } else {
                        throw new IllegalStateException(v.getClass().getName() +
                                " should be bound to a Boolean, not a " +
                                (data == null ? "<unknown type>" : data.getClass()));
                    }
                } else if (v instanceof TextView) {
                    // Note: keep the instanceof TextView check at the bottom of these
                    // ifs since a lot of views are TextViews (e.g. CheckBoxes).
                    setViewText((TextView) v, text);
                } else if (v instanceof ImageView) {
                    if (data instanceof Integer) {
                        setViewImage((ImageView) v, (Integer) data);                            
                    } else if (data instanceof Bitmap){
                        setViewImage((ImageView) v, (Bitmap)data);
                    } else {
                        setViewImage((ImageView) v, text);
                    }
                } else {
                    throw new IllegalStateException(v.getClass().getName() + " is not a " +
                            " view that can be bounds by this SimpleAdapter");
                }
            }
        }
    }
}



private void setViewImage(ImageView v, Bitmap bmp){
    v.setImageBitmap(bmp);
}



}

This class behave exactly like the original class (SimpleAdapter)