我在scinping的方法doInBackground中有一个问题，在得到图片的链接后我也调用其他AsyncTask来下载这个的位图。但是当我将位图放在我的ImageView中时无效。
活动类：
ListView listView = (ListView) findViewById(R.id.listScraping);
ArrayList<Scraping> myList = new ArrayList<Scraping>();
myAdapter = new MyAdapter(getApplicationContext(),myList);
myList.add(new Scraping("https: //www.youtube.com/watch?v=HMUDVMiITOU",myAdapter,myList));
listView.setAdapter(myAdapter);
适配器类：
public class MyAdapter extends BaseAdapter {
private Context ctx;
private ArrayList<Scraping> arrayList;
private LayoutInflater mInflater;
public MyAdapter(Context ctx,ArrayList<Scraping> arrayList)
{
this.arrayList = arrayList;
this.ctx = ctx;
this.mInflater = LayoutInflater.from(ctx);
}
@Override
public int getCount() {
return this.arrayList.size();
}
@Override
public Object getItem(int position) {
return this.arrayList.get(position);
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
Scraping scraping = this.arrayList.get(position);
if(convertView == null)
{
Log.d("CREATE","view "+ position);
holder = new ViewHolder();
convertView = this.mInflater.inflate(R.layout.preview_scraping,parent,false);
holder.tvTitle = (TextView) convertView.findViewById(R.id.tituloScrap);
holder.tvDescription = (TextView) convertView.findViewById(R.id.descripcionScrap);
holder.ivThumbnail = (ImageView) convertView.findViewById(R.id.thumbnailScrap);
convertView.setTag(holder);
}
else
{
Log.d("EXISTS","view "+ position);
holder = (ViewHolder) convertView.getTag();
}
holder.tvTitle.setText(scraping.getTitle()+" :: " + position);
holder.tvDescription.setText(scraping.getDescription()+" :: " + position);
holder.ivThumbnail.setImageBitmap(scraping.getImagen());
return convertView;
}
private class ViewHolder
{
TextView tvTitle;
TextView tvDescription;
ImageView ivThumbnail;
};
}
刮痧课
public class Scraping {
private String url;
private String title;
private String description;
private Bitmap imagen;
private MyAdapter adapter;
private String titleScraping;
private String descriptionScraping;
private Bitmap imagenScraping;
private ArrayList<Scraping> arrayList;
public Scraping(String url,MyAdapter adapter,ArrayList<Scraping> arrayList)
{
this.url = url;
this.adapter = adapter;
this.arrayList = arrayList;
scraping_url();
}
public Scraping(String title, String description) {
this.title = title;
this.description = description;
}
public Scraping(String title, String description,Bitmap imagen) {
this.title = title;
this.description = description;
this.imagen = imagen;
}
public Bitmap getImagen() {
return imagen;
}
public void setImagen(Bitmap imagen) {
this.imagen = imagen;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public void scraping_url()
{
final String urlStr = this.url;
new AsyncTask<Void,Void,Void>()
{
@Override
protected Void doInBackground(Void... params) {
try {
Document doc = Jsoup.connect(urlStr).userAgent("Mozilla/5.0 (Macintosh; U; Intel Mac OS X; de-de) AppleWebKit/523.10.3 (KHTML, like Gecko) Version/3.0.4 Safari/523.10").referrer("http://www.google.com").get();
String word_google = "google";
String word_twitter = "twitter";
String title , description , image ;
image = "";
title = doc.title();
if(title.equals(""))
{
title= doc.select("meta[property=og:title]").attr("content");
}
description = doc.select("meta[name=description]").attr("content");
if(description.equals(""))
{
description= doc.select("meta[name=keywords]").attr("content");
}
if(description.equals(""))
{
description= doc.select("meta[property=og:description]").attr("content");
}
if(description.equals(""))
{
description = title;
}
Elements src_img = doc.select("img[src~=(?i)\\.(png|jpe?g)]");
if(src_img.size() > 0 )
{
image = src_img.first().attr("content");
}
if(image.equals(""))
{
image = doc.select("meta[property=og:image]").attr("content");
}
if(image.equals(""))
{
src_img = doc.select("link[href~=(?i)\\.(ico)]");
if(src_img.size() > 0 )
{
if(urlStr.contains(word_twitter) && image.equals(""))
{
image = src_img.first().attr("href");
}
else
{
image = urlStr + src_img.first().attr("href");
}
}
}
if(urlStr.contains(word_google) && image.equals(""))
{
image = urlStr + "/images/google_favicon_128.png";
}
titleScraping = title;
descriptionScraping = description;
if(image.length() > 0)
{
imagenScraping = download_bitmap_thumbnail(image);
}
return null;
}catch (IOException e)
{
e.printStackTrace();
return null;
}
}
@Override
protected void onPostExecute(Void voids) {
setTitle(titleScraping);
setDescription(descriptionScraping);
setImagen(imagenScraping);
adapter.notifyDataSetChanged();
}
}.execute();
}
public Bitmap download_bitmap_thumbnail(String thumbnail)
{
//set image
DownloadingImage download = new DownloadingImage(thumbnail);
download.execute();
return download.getBitmap();
}
}
DownloadingImage类：
public class DownloadingImage extends AsyncTask<String, Void, Bitmap>
{
private String url;
private Bitmap bitmap;
public DownloadingImage(String url)
{
this.url = url;
}
protected Bitmap doInBackground(String... urls)
{
Bitmap mIcon11 = null;
try {
InputStream in = new java.net.URL(this.url).openStream();
mIcon11 = BitmapFactory.decodeStream(in);
} catch (Exception e)
{
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return mIcon11;
}
protected void onPostExecute(Bitmap result)
{
setBitmap(result);
}
public Bitmap getBitmap() {
return bitmap;
}
public void setBitmap(Bitmap bitmap) {
this.bitmap = bitmap;
}
}
答案 0 :(得分：0)
谢谢你帮助了我，最后我解决了这个帖子的问题。
Make AsyncTask wait for other AsyncTasks
我更改了此代码片段：
public Bitmap download_bitmap_thumbnail(String thumbnail)
{
//set image
DownloadingImage download = new DownloadingImage(thumbnail);
download.execute();
return download.getBitmap();
}
有：
public void download_bitmap_thumbnail(String thumbnail)
{
//set image
DownloadingImage download = new DownloadingImage(thumbnail);
setImagen(download.doInBackground());
}
：）