如何在ListView中显示Bitmap图像（转载）

我在一个小项目中需要用到将SD卡中的图片读出后，压缩，再进行显示。在编程过程中，使用SimpleAdapter适配器时，图片资源的ID均需是程序内的本地资源。在网上找到了两个实现方法，第一个我验证了可以实现，第二个比较繁琐还未验证。

1.实现ViewBinder()接口（http://hi.baidu.com/helloworldtoo/blog/item/ad3bb738925b62ffb211c7ea.html）

一般来说，在用simpleAdapter适配器时，我们所要显示的图片资源都是程序内的本地资源，而且是以资源的ID(Resources ID)形式来表现的。但是有时候我们需要用这个适配器来显示网上的远程图片时，该如何直接显示呢？方法是实现ViewBinder()这个接口，在里面定义数据和视图的匹配关系。实例代码如下：

SimpleAdapter simpleAdapter = new SimpleAdapter(this, setData(), R.layout.list, new String[] {'Name', 'Image' }, new int[] { R.id.list_Name, R.id.list_Image }); simpleAdapter.setViewBinder(new ListViewBinder());private class ListViewBinder implements ViewBinder { @Override public boolean setViewValue(View view, Object data, String textRepresentation) { // TODO Auto-generated method stub if((view instanceof ImageView) && (data instanceof Bitmap)) { ImageView imageView = (ImageView) view; Bitmap bmp = (Bitmap) data; imageView.setImageBitmap(bmp); return true; } return false; } }

 

2.重写SimpleAdapter(http://www./20110303/196.html)

myAdapter listItemAdapter;
listItemAdapter =new myAdapter(this,listItem,R.layout.favlv,newString[]{'ItemImage','ItemTv'},newint[]{R.id.ItemImage,R.id.ItemTv});  
下面是myAdapter的实现方法：

package com.BottomMenu;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 myAdapter extends SimpleAdapter { private int[] mTo; private String[] mFrom; private ViewBinder mViewBinder; private List> mData; private int mResource; private int mDropDownResource; private LayoutInflater mInflater; public myAdapter(Context context, List> 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]); // if(data 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); } 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 { 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); } public void setViewImage(ImageView v, Bitmap bm) { ((ImageView) v).setImageBitmap(bm); }};