From AS2 to AS3 loading external images

actionscript-2actionscript-3flashimagemigration

I'm converting some Actionscript code from AS2 tp AS3, and I've eventually managed to get most of it to work again (it's allmost a totally different language, sharing just a little syntax similarity). One of the last things that still doesn't work, is the code for loading an external image.

Perhaps this has changed in AS3 but I really thought it was strange that to load an image you use loadVideo, why not loadImage? (on the other hand a flash application is constantly called a flash video even when it's not used for animation at all). This doesn't work anymore, and what I've found is a pretty complex code that is said to replace this oneliner imageholder.loadVideo(url); is this:

var urlreq:URLRequest = new URLRequest(url);
var theloader:Loader = new URLLoader();
theloader.load(urlreq);
theloader.addEventListener(Event.COMPLETE, function(event:Event):void {
        imageholder.addChild(theloader);
    }
);

But this doesn't work.. What I am doing wrong, and is there a more suited function to load images in AS3?

Best Answer

One of most common problems people have with loaders is what they listen to for events. You need to make sure you're listening to the loader.contentLoaderInfo for most events, not the loader itself. That was the main problem in the example you provided.

//this is WRONG
loader.addEventListener(Event.COMPLETE, onLoad);

//this is RIGHT
loader.contentLoaderInfo.addEventListener(Event.COMPLETE, onLoad);

Related Solutions

Android – How to lazy load images in ListView in Android

Here's what I created to hold the images that my app is currently displaying. Please note that the "Log" object in use here is my custom wrapper around the final Log class inside Android.

package com.wilson.android.library;

/*
 Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License.  You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.
*/
import java.io.IOException;

public class DrawableManager {
    private final Map<String, Drawable> drawableMap;

    public DrawableManager() {
        drawableMap = new HashMap<String, Drawable>();
    }

    public Drawable fetchDrawable(String urlString) {
        if (drawableMap.containsKey(urlString)) {
            return drawableMap.get(urlString);
        }

        Log.d(this.getClass().getSimpleName(), "image url:" + urlString);
        try {
            InputStream is = fetch(urlString);
            Drawable drawable = Drawable.createFromStream(is, "src");


            if (drawable != null) {
                drawableMap.put(urlString, drawable);
                Log.d(this.getClass().getSimpleName(), "got a thumbnail drawable: " + drawable.getBounds() + ", "
                        + drawable.getIntrinsicHeight() + "," + drawable.getIntrinsicWidth() + ", "
                        + drawable.getMinimumHeight() + "," + drawable.getMinimumWidth());
            } else {
              Log.w(this.getClass().getSimpleName(), "could not get thumbnail");
            }

            return drawable;
        } catch (MalformedURLException e) {
            Log.e(this.getClass().getSimpleName(), "fetchDrawable failed", e);
            return null;
        } catch (IOException e) {
            Log.e(this.getClass().getSimpleName(), "fetchDrawable failed", e);
            return null;
        }
    }

    public void fetchDrawableOnThread(final String urlString, final ImageView imageView) {
        if (drawableMap.containsKey(urlString)) {
            imageView.setImageDrawable(drawableMap.get(urlString));
        }

        final Handler handler = new Handler() {
            @Override
            public void handleMessage(Message message) {
                imageView.setImageDrawable((Drawable) message.obj);
            }
        };

        Thread thread = new Thread() {
            @Override
            public void run() {
                //TODO : set imageView to a "pending" image
                Drawable drawable = fetchDrawable(urlString);
                Message message = handler.obtainMessage(1, drawable);
                handler.sendMessage(message);
            }
        };
        thread.start();
    }

    private InputStream fetch(String urlString) throws MalformedURLException, IOException {
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpGet request = new HttpGet(urlString);
        HttpResponse response = httpClient.execute(request);
        return response.getEntity().getContent();
    }
}

R – Loading symbols from an AS2 SWF into an AS3 application

You're probably best of by loading your legacy swf into an AVM1Movie object in AS3.

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