android ListView中自訂SimpleAdapter動態添加ratingBar及圖片更新

                                                                

android中listView的實現有多種方式，但是當我們利用simpleAdapter實現listView的時候，SimpleAdapter並沒有提供顯示一個ratingBar的功能（即上面的星星用來評分的控制項）。要實現上面的功能，我們可以通過繼承SimpleAdapter類重寫其中一些方法來實現。下面即是此類的實現：

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[]) {      //備忘1Bitmap 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());  //備忘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類繼承自SimpleAdapter，我們要實現的效果主要在 private void bindView(int position, View view) 函數中添加（更改）就行。這個函數中相當於將控制項與資料對應，然後在應用此類時，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內容與上面圖中顯示的listView中的item內容一致。

myListView.setAdapter(myListAdapter); 

在備忘2處實現了當View是一個RatingBar的類型時也能在listView中顯示的效果的功能。此時我們的data就是我們要顯示的ratingBar中star的個數（也就是評分數） ！！！

在備忘1處，我們將網路或者是從資料庫等地方取來的圖片資料（Blob類型然後轉成byte[]類型）（比如我們之前可以使用

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

 將圖片轉成byte[]類型儲存）。扯遠了！這個轉換在這篇文章中有將詳細的說明。

總之備忘一處就是運用上面添加ratingBar同樣的原理將byte[]類型的圖片還原（這是原來的SimpleAdapter中沒有實現的）。

記錄下自己的所學，雖然淺薄！！！如果我是一隻蝸牛，那就只能慢慢向上爬！