如何在ListView中显示Bitmap图像

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

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.pocketdigi.com/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<? extends Map<String, ?>> mData;

private int mResource;
private int mDropDownResource;
private LayoutInflater mInflater;

public myAdapter(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]);
// 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);
}

};