Android 查看可展开列表中的图像列表
我已经做了一个可扩展的列表,其中孩子的(子项)显示可绘图文件夹或文本中的图像 我想对来自网络的图像做同样的事情。因此,我也使用asynctask来避免 此代码位于我的ExpandableListAdapter中,我在其中初始化项和子项。Drawable和ImageView是全局定义的,因此所有函数都可以访问它们,而无需作为参数发送Android 查看可展开列表中的图像列表,android,multithreading,image,android-asynctask,expandablelistview,Android,Multithreading,Image,Android Asynctask,Expandablelistview,我已经做了一个可扩展的列表,其中孩子的(子项)显示可绘图文件夹或文本中的图像 我想对来自网络的图像做同样的事情。因此,我也使用asynctask来避免 此代码位于我的ExpandableListAdapter中,我在其中初始化项和子项。Drawable和ImageView是全局定义的,因此所有函数都可以访问它们,而无需作为参数发送 Drawable drawable; ImageView imgView; @Override public View getChildView(int grou
Drawable drawable;
ImageView imgView;
@Override
public View getChildView(int groupPosition, int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
String child = childList[groupPosition][childPosition];
if(child.equalsIgnoreCase("none")){
ImageView i = new ImageView(context);
i.setImageResource(R.drawable.blank_image_for_view_business);
i.setPadding(0, 0, 0, 0);
return i ;
}
else if(child.startsWith("http")){
imgView = new ImageView(context);
new asyTask();
return imgView;
}else{
TextView tv = new TextView(context);
tv.setText(childList[groupPosition][childPosition]);
tv.setPadding(30, 0, 0, 0);
return tv;
}
}
private Drawable LoadImageFromWeb(String url){
try{
InputStream is = (InputStream) new URL(url).getContent();
Drawable d = Drawable.createFromStream(is, "src name");
return d;
}catch (Exception e) {
System.out.println("Exc="+e);
return null;
}
}
这是我的异步类:
private class asyTask extends AsyncTask<String, Void, Integer> {
@Override
protected void onPreExecute() {
super.onPreExecute();
//show a progress bar
}
@Override
protected void onPostExecute(Integer result) {
super.onPostExecute(result);
imgView.setImageDrawable(drawable);
}
@Override
protected Integer doInBackground(String... params) {
drawable = LoadImageFromWeb("http://www.ettinger.co.uk/var/ezflow_site/storage/images/collections/ettinger/ettinger-walkie-pen/lifestyle-navy-walkie-pen/navy-walkie-pen-gallery/wlkp_pens_navy-2/20569-2-eng-GB/wlkp_pens_navy-2.jpg");
return 0;
}
私有类asyTask扩展了AsyncTask{
@凌驾
受保护的void onPreExecute(){
super.onPreExecute();
//显示进度条
}
@凌驾
受保护的void onPostExecute(整数结果){
super.onPostExecute(结果);
imgView.setImageDrawable(可绘制);
}
@凌驾
受保护的整数doInBackground(字符串…参数){
drawable=LoadImageFromWeb(“http://www.ettinger.co.uk/var/ezflow_site/storage/images/collections/ettinger/ettinger-walkie-pen/lifestyle-navy-walkie-pen/navy-walkie-pen-gallery/wlkp_pens_navy-2/20569-2-eng-GB/wlkp_pens_navy-2.jpg");
返回0;
}
目前,在可展开列表中,我只能看到来自drawable文件夹和textview的图像,但没有来自internet的图像。有什么问题吗?我已经解决了
getChildView():
这将调用以下方法:
private Drawable ImageOperations(Context ctx, String url, String saveFilename) {
try {
InputStream is = (InputStream) this.fetch(url);
Drawable d = Drawable.createFromStream(is, "src");
return d;
} catch (MalformedURLException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
public Object fetch(String address) throws MalformedURLException,IOException {
URL url = new URL(address);
Object content = url.getContent();
return content;
}
因此,无需创建其他私有类来在ExpandableListAdapter类中显示来自internet的图像。它可以工作。您的AndroidManifest.xml中是否具有internet权限?您还应该使用处理程序来设置imageview的可绘制性。是的,我具有internet权限。在这种情况下,处理程序如何提供帮助?你能举个例子吗?因为你在一个不同于主线程的线程中,你不能设置可绘制的。只需定义一个附加到UI线程的新处理程序,或者你可以使用runonmainthread.activity.runOnUiThread(new Runnable(){@Override public void run(){//你的代码在这里运行在GUI线程中});
private Drawable ImageOperations(Context ctx, String url, String saveFilename) {
try {
InputStream is = (InputStream) this.fetch(url);
Drawable d = Drawable.createFromStream(is, "src");
return d;
} catch (MalformedURLException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
public Object fetch(String address) throws MalformedURLException,IOException {
URL url = new URL(address);
Object content = url.getContent();
return content;
}