android ListView中自定义SimpleAdapter动态添加ratingBar及图片更新

              

                         

android中listView的实现有多种方式，但是当我们利用simpleAdapter实现listView的时候，SimpleAdapter并没有提供显示一个ratingBar的功能（即上面的星星用来评分的控件）。要实现上面的功能，我们可以通过继承SimpleAdapter类重写其中一些方法来实现。

package nate.android.Service;

import java.util.List;
import java.util.Map;
import com.nate.wte.LocalSql.StoresInfoDB;
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.RatingBar;
import android.widget.SimpleAdapter;
import android.widget.TextView;

public class MySimpleAdapter extends SimpleAdapter {
    private int[] mTo;
    private String[] mFrom;
    private ViewBinder mViewBinder;
    private List<? extends Map<String, ?>> mData;
    private int mResource;
    private int mDropDownResource;
    private LayoutInflater mInflater;
    public MySimpleAdapter(Context context,
            List<? extends Map<String, ?>> data, int resource, String[] from,
            int[] to) {
        super(context, data, resource, from, to);
        mData = data;
        mResource = mDropDownResource = resource;
        mFrom = from;
        mTo = to;
        mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }
     /**
     * @see android.widget.Adapter#getView(int, View, ViewGroup)
     */
    public View getView(int position, View convertView, ViewGroup parent) {
        return createViewFromResource(position, convertView, parent, mResource);
    }
    private View createViewFromResource(int position, View convertView,
            ViewGroup parent, int resource) {
        View v;
        if (convertView == null) {
            v = mInflater.inflate(resource, parent, false);

            final int[] to = mTo;
            final int count = to.length;
            final View[] holder = new View[count];

            for (int i = 0; i < count; i++) {
                holder[i] = v.findViewById(to[i]);
            }

            v.setTag(holder);
        } else {
            v = convertView;
        }
        bindView(position, v);

        return v;
    }

    private void bindView(int position, View view) {
        final Map dataSet = mData.get(position);
        if (dataSet == null) {
            return;
        }
        final ViewBinder binder = mViewBinder;
        final View[] holder = (View[]) view.getTag();
        final String[] from = mFrom;
        final int[] to = mTo;
        final int count = to.length;

        for (int i = 0; i < count; i++) {
            final View v = holder[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 {
                            throw new IllegalStateException(v.getClass().getName() +
                                    " should be bound to a Boolean, not a " + 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);
                        ((TextView) v).setText(text);
                    } else if (v instanceof ImageView) {
                        if (data instanceof Integer) {
                            setViewImage((ImageView) v, (Integer) data);
                        }
                        else if(data instanceof byte[]) {      //备注1
                                Bitmap bmp;
                                byte[] image = (byte[])data;
                                if(b.length!=0){
                                bmp = BitmapFactory.decodeByteArray(b, 0, b.length);
                                ((ImageView) v).setImageBitmap(bmp);
                            }
                        }
                    else if(v instanceof RatingBar){
                        float score = Float.parseFloat(data.toString());  //备注2
                        ((RatingBar)v).setRating(score);
                    }
                    else {
                        throw new IllegalStateException(v.getClass().getName() + " is not a " +
                                " view that can be bounds by this SimpleAdapter");
                    }
                }
            }
        }
    }

    public void setViewImage(ImageView v, int value) {
        v.setImageResource(value);
}

以上MySimpleAdapter类继承自SimpleAdapter，我们要实现的效果主要在 private void bindView(int position, View view) 函数中添加（更改）就行。这个函数中相当于将控件与数据对应，然后在应用此类时，如下

MySimpleAdapter myListAdapter = new MySimpleAdapter(this,list,R.layout.stores,
                    new String[]{"store_name", "store_score","store_pic","store_scores","phone"},
                    new int[]{R.id.store_name, R.id.store_score,R.id.store_pic,R.id.store_score_bar,R.id.showPhone});

此adapter内容与上面图中显示的listView中的item内容一致。

myListView.setAdapter(myListAdapter);

在备注2处实现了当View是一个RatingBar的类型时也能在listView中显示的效果的功能。此时我们的data就是我们要显示的ratingBar中star的个数（也就是评分数） ！！！

在备注1处，我们将网络或者是从数据库等地方取来的图片数据（Blob类型然后转成byte[]类型）（比如我们之前可以使用

public byte[] Bitmap2Bytes(Bitmap bm){
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
         bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
         return baos.toByteArray();
        }

 将图片转成byte[]类型存储）。扯远了！总之备注一处就是运用上面添加ratingBar同样的原理将byte[]类型的图片还原（这是原来的SimpleAdapter中没有实现的）。