From da9955cd67062c29f6b6b922cd9b05f5a0f68b56 Mon Sep 17 00:00:00 2001
From: Robert Kolner <robert.kolner@gmail.com>
Date: Tue, 17 Jan 2012 23:58:25 +0100
Subject: [PATCH] Lazy loading of dancing images.

---
 .../app/network/ImageLoader.java              | 57 +++++++++++++++++++
 .../app/ui/EventListActivity.java             | 22 +------
 2 files changed, 60 insertions(+), 19 deletions(-)
 create mode 100644 src/com/studentersamfundet/app/network/ImageLoader.java

diff --git a/src/com/studentersamfundet/app/network/ImageLoader.java b/src/com/studentersamfundet/app/network/ImageLoader.java
new file mode 100644
index 0000000..8ab27e6
--- /dev/null
+++ b/src/com/studentersamfundet/app/network/ImageLoader.java
@@ -0,0 +1,57 @@
+package com.studentersamfundet.app.network;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.security.InvalidParameterException;
+import java.util.HashMap;
+import java.util.Map;
+
+import android.graphics.drawable.Drawable;
+import android.net.Uri;
+import android.os.AsyncTask;
+import android.util.Log;
+import android.widget.ImageView;
+
+public class ImageLoader extends AsyncTask<String, Void, Drawable> {
+	public final static Map<String, Drawable> cache = new HashMap<String, Drawable>();
+	private final ImageView view;
+	
+	public ImageLoader(ImageView... views)  {
+		if (views.length > 1)
+			throw new InvalidParameterException("Too many arguments to the function!");
+		
+		this.view = views[0];
+	}
+		
+	@Override
+	protected Drawable doInBackground(String... params) {
+		if (params.length > 1)
+			throw new InvalidParameterException("Too many arguments to the function!");
+				
+		Drawable d = cache.get(params[0]);
+		if (d != null)
+			return d;
+		
+		try {
+			HttpURLConnection con = (HttpURLConnection)new URL(params[0]).openConnection();
+		    InputStream is = con.getInputStream();
+		    		
+			d = Drawable.createFromStream(is, params[0].toString());
+			cache.put(params[0], d);
+		} catch (IOException e) {
+			Log.e("DNSapp", "An exception has occured while downloading images!", e);
+		}
+		return d;
+	}
+	
+	@Override
+	protected void onPostExecute(Drawable result) {
+		super.onPostExecute(result);
+		
+		if (result != null && view != null) {
+			view.setImageDrawable(result);
+		}
+	}
+}
diff --git a/src/com/studentersamfundet/app/ui/EventListActivity.java b/src/com/studentersamfundet/app/ui/EventListActivity.java
index 561eb24..3e72b32 100644
--- a/src/com/studentersamfundet/app/ui/EventListActivity.java
+++ b/src/com/studentersamfundet/app/ui/EventListActivity.java
@@ -1,18 +1,12 @@
 package com.studentersamfundet.app.ui;
 
 import java.io.IOException;
-import java.io.InputStream;
-import java.net.HttpURLConnection;
-import java.net.MalformedURLException;
-import java.net.URL;
 import java.text.SimpleDateFormat;
 
 import org.w3c.dom.NodeList;
 
 import android.app.Dialog;
 import android.content.Intent;
-import android.graphics.Bitmap;
-import android.graphics.BitmapFactory;
 import android.os.AsyncTask;
 import android.os.Bundle;
 import android.text.Html;
@@ -36,6 +30,7 @@ import com.studentersamfundet.app.Event;
 import com.studentersamfundet.app.FeedFetcher;
 import com.studentersamfundet.app.R;
 import com.studentersamfundet.app.RSSParserProgram;
+import com.studentersamfundet.app.network.ImageLoader;
 import com.studentersamfundet.app.ui.ChooseCategoryDialog.Callback;
 
 public class EventListActivity extends BaseDnsActivity {
@@ -114,19 +109,8 @@ public class EventListActivity extends BaseDnsActivity {
     			
     			/* Set images: */
     			ImageView imageView = (ImageView) row.findViewById(R.id.event_list_row_image);
-    			try {
-    			    String urlStr = e.getImageUri(imageSize).toString();
-    			    URL ulrn = new URL(urlStr);
-    			    HttpURLConnection con = (HttpURLConnection)ulrn.openConnection();
-    			    InputStream is = con.getInputStream();
-    			    Bitmap bmp = BitmapFactory.decodeStream(is);
-    			    
-    			    if (null != bmp) {
-    			        imageView.setImageBitmap(bmp);
-    			    }
-
-			    } catch (MalformedURLException ex1){ /* TODO: Default image */
-			    } catch (IOException ex2) { /* TODO: Default image */ }
+    			ImageLoader loader = new ImageLoader(imageView);
+				loader.execute(e.getImageUri(imageSize).toString());
     			
     			
     			/* Set text: */