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。下面即是此类的实现：

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！这个转换在这篇文章中有将详细的说明。

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）。

记录下自己的所学，虽然浅薄！！！如果我是一只蜗牛，那就只能慢慢向上爬！