问题描述
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我正在从URL获取图像。我在列表视图中使用imageview。我想将位图图像列表添加到列表项的每一行中。我使用了SimpleAdapter，但是imageview显示为空白。我的代码在下面！
ArrayList<HashMap<String,Bitmap>> mylist = new ArrayList<HashMap<String,Bitmap>>();
Bundle bundle = this.getIntent().getExtras();
get = bundle.getString(\"name\");
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(\"http://www.propertyhookup.com/mobile/propertylist.PHP\");
nameValuePairs = new ArrayList<NameValuePair>(1);
nameValuePairs.add(new BasicNameValuePair(\"zipcode\",get.trim()));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
httpentity entity = response.getEntity();
is = entity.getContent();
}catch(Exception e){
Toast.makeText(getApplicationContext(),e.getMessage(),Toast.LENGTH_LONG).show();
}
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,\"iso-8859-1\"),8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + \"\\n\");
}
is.close();
result=sb.toString();
}catch(Exception e){
Toast.makeText(getApplicationContext(),Toast.LENGTH_LONG).show();
}
if(result.length()<= 7){
Toast.makeText(getApplicationContext(),\"No properties for this zipcode or check your zipcode \",Toast.LENGTH_LONG).show();
//text.setText(\"No properties for this zipcode or check your zipcode\");
}
else{
try{
jArray = new JSONObject(result);
}catch(JSONException e){
Toast.makeText(getApplicationContext(),Toast.LENGTH_LONG).show();
}
//JSONObject json = JSONfunctions.getJSONfromURL(\"http://192.168.1.111/propertyhookup.com/mobile/propertylist.PHP\");
try{
JSONArray earthquakes = jArray.getJSONArray(\"earthquakes\");
for(int i=0;i<10;i++){
map = new HashMap<String,Bitmap>();
//HashMap<String,Drawable> map1 = new HashMap<String,Drawable>();
JSONObject e = earthquakes.getJSONObject(i);
if(e.getString(\"property_type\").contains(\"1\")) {
proptype =\"Single Family Home\";
}else if(e.getString(\"property_type\").contains(\"2\")) {
proptype=\"Condo\";
}else if(e.getString(\"property_type\").contains(\"3\")) {
proptype=\"Townhouse\";
}
if(e.getString(\"estimated_price\").contains(\"0\")) {
estimate = \"Not Enough Market Value\";
//estimat = (TextView) findViewById(R.id.estimat);
//estimat.setTextColor(Color.rgb(0,23));
}else {
estimate = \"$\"+e.getString(\"estimated_price\");
}
photo = e.getString(\"photo1\");
drawable = LoadImageFromWebOperations(photo);
//text.setimageDrawable(d);
try
{
aURL = new URL(photo);
}
catch (MalformedURLException e1)
{
// Todo Auto-generated catch block
e1.printstacktrace();
}
URLConnection conn = null;
try
{
conn = aURL.openConnection();
}
catch (IOException e1)
{
// Todo Auto-generated catch block
e1.printstacktrace();
}
try
{
conn.connect();
}
catch (IOException e1)
{
// Todo Auto-generated catch block
e1.printstacktrace();
}
InputStream is = null;
try
{
is = conn.getInputStream();
}
catch (IOException e1)
{
// Todo Auto-generated catch block
e1.printstacktrace();
}
BufferedInputStream bis = new
BufferedInputStream(is,8*1024);
Bitmap bm = BitmapFactory.decodeStream(bis);
map.put(photos,bm);
mylist.add(map);
}
}catch(JSONException e) {
Toast.makeText(getApplicationContext(),Toast.LENGTH_LONG).show();
}
SimpleAdapter adapter = new SimpleAdapter(this,mylist,R.layout.main4,new String[] { \"percent\",\"propertyid\",\"cityname\",\"statecode\",\"propertytype\",\"footage\",\"bathroom\",\"bedroom\",\"price\",\"estimated\",\"photos\" },new int[] { R.id.percent,R.id.property_id,R.id.city_name,R.id.state_code,R.id.prop_type,R.id.foot,R.id.bath,R.id.bed,R.id.list,R.id.estimat,R.id.image});
setlistadapter(adapter);
解决方法
我认为是因为您正在从Web下载图像，并且需要在ASYNC中执行这些操作，才能看到无痛的threth下载图像，然后刷新图像视图。
, 基本上，简单的适配器会自动将一些资源ID或URI绑定到行布局的imageview。
但是它不支持位图。
这是一个问题，因为每个需要管理位图的人都知道，我们经常必须减小图片的大小，以防止内存不足的异常。
但是，如果要将图像添加到listView中，则仅提供URI就无法减小图像的大小。所以这是解决方案：
我修改了simpleAdapter使其能够处理位图。
将该类添加到您的项目中，并使用它代替simpleAdapter。
然后，不传递图像的URI或ressourceId，而是传递Bitmap！
以下是代码：
import java.util.HashMap;
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 ExtendedSimpleAdapter extends SimpleAdapter{
List<? extends Map<String,?>> map; // if fails to compile,replace with List<HashMap<String,Object>> map
String[] from;
int layout;
int[] to;
Context context;
LayoutInflater mInflater;
public ExtendedSimpleAdapter(Context context,List<? extends Map<String,?>> data,// if fails to compile,do the same replacement as above on this line
int resource,String[] from,int[] to) {
super(context,data,resource,from,to);
layout = resource;
map = data;
this.from = from;
this.to = to;
this.context = context;
}
@Override
public View getView(int position,View convertView,ViewGroup parent) {
mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
return this.createViewFromResource(position,convertView,parent,layout);
}
private View createViewFromResource(int position,ViewGroup parent,int resource) {
View v;
if (convertView == null) {
v = mInflater.inflate(resource,false);
} else {
v = convertView;
}
this.bindView(position,v);
return v;
}
private void bindView(int position,View view) {
final Map dataSet = map.get(position);
if (dataSet == null) {
return;
}
final ViewBinder binder = super.getViewBinder();
final int count = to.length;
for (int i = 0; i < count; i++) {
final View v = view.findViewById(to[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,text);
}
if (!bound) {
if (v instanceof Checkable) {
if (data instanceof Boolean) {
((Checkable) v).setChecked((Boolean) data);
} 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 {
throw new IllegalStateException(v.getClass().getName() +
\" should be bound to a Boolean,not a \" +
(data == null ? \"<unknown type>\" : 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 {
setViewImage((ImageView) v,text);
}
} else {
throw new IllegalStateException(v.getClass().getName() + \" is not a \" +
\" view that can be bounds by this SimpleAdapter\");
}
}
}
}
}
private void setViewImage(ImageView v,Bitmap bmp){
v.setImageBitmap(bmp);
}
}
private Bitmap loadImageFromNetwork(String url) throws MalformedURLException,IOException {
HttpURLConnection conn = (HttpURLConnection) (new URL(url)).openConnection();
conn.connect();
return BitmapFactory.decodeStream(new FlushedInputStream(conn.getInputStream()));
}