我的画廊有问题，速度很慢而且滞后。我正在使用图像适配器从服务器加载图像：
package com.example.ocenitaksi;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import org.apache.http.client.utils.URLEncodedUtils;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
public class ImageAdapter extends BaseAdapter {
private Context context;
private final String[] mobileValues;
public ImageAdapter(Context context, String[] mobileValues) {
this.context = context;
this.mobileValues = mobileValues;
}
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View gridView;
if (convertView == null) {
gridView = new View(context);
// get layout from mobile.xml
gridView = inflater.inflate(R.layout.mobile, null);
// set image based on selected text
ImageView imageView = (ImageView) gridView
.findViewById(R.id.grid_item_image);
// ubacivanje slika za string
String mobile = mobileValues[position];
if (mobile.equals(MainActivity.imena[position])) {
//imageView.setImageURI("http://24.media.tumblr.com/avatar_a400b4dbb80e_64.png");
Bitmap bitmap=null;;
mobile = mobile.replace(" ", "_");
bitmap = DownloadImage("http://android.yunews.net/images/"+mobile+".png");
imageView.setImageBitmap(bitmap);
}
}
else {
gridView = (View) convertView;
}
return gridView;
}
@Override
public int getCount() {
return mobileValues.length;
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public long getItemId(int position) {
return 0;
}
private InputStream OpenHttpConnection(String urlString) throws IOException {
InputStream in = null;
int response = -1;
URL url = new URL(urlString);
URLConnection conn = url.openConnection();
if (!(conn instanceof HttpURLConnection))
throw new IOException("Not an HTTP connection");
try {
HttpURLConnection httpConn = (HttpURLConnection) conn;
httpConn.setAllowUserInteraction(false);
httpConn.setInstanceFollowRedirects(true);
httpConn.setRequestMethod("GET");
httpConn.connect();
response = httpConn.getResponseCode();
if (response == HttpURLConnection.HTTP_OK) {
in = httpConn.getInputStream();
}
} catch (Exception ex) {
throw new IOException("Error connecting");
}
return in;
}
private Bitmap DownloadImage(String URL) {
Bitmap bitmap = null;
InputStream in = null;
try {
in = OpenHttpConnection(URL);
bitmap = BitmapFactory.decodeStream(in);
in.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
return bitmap;
}
}
这是我主要活动的一部分。
private class LongOperation extends AsyncTask<String, Void, String>
{
protected void onPreExecute()
{
progressDialog = new ProgressDialog(MainActivity.this);
progressDialog.setTitle("Molimo sacekajte...");
progressDialog.setMessage("Ucitavam taksi sluzbe...");
progressDialog.setCancelable(true);
progressDialog.show();
}
protected String doInBackground(String... params)
{
niz = new JSONFunkcije().ListaSluzbi();
imena= new String[niz.size()];
Iterator<String> it= niz.iterator();
for (int i=0;i<niz.size();i++)
imena[i]=it.next();
slicice = new ImageAdapter(MainActivity.this, imena);
return null;
}
protected void onPostExecute(String result)
{
progressDialog.dismiss();
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
//Button dugme1 = (Button) findViewById(R.id.dugme1);
///params.height = "50dpi";
//dugme1.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, 100));
Gallery gridView = (Gallery) findViewById(R.id.gallery1);
gridView.setAdapter(slicice);
//kraj ucitvanja
//gridView.setAdapter(adapter);
gridView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
// Sending image id to FullScreenActivity
Intent i = new Intent(getApplicationContext(), TaksiDetalji.class);
// passing array index
i.putExtra("id", imena[position]);
startActivity(i);
}
});
}
});
System.gc();
}
}
我正在从 OnCrate 调用 LongOperation：
mytask = new LongOperation();
mytask.execute();
ImageAdapter 有问题吗？太多的调用，下载？我试图缓存图像，但失败了。