Add LoaderImageView

src/com/blundell/tut/LoaderImageView.java

@@ -0,0 +1,156 @@
+package com.blundell.tut;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.MalformedURLException;
+import java.net.URL;
+
+import android.content.Context;
+import android.graphics.drawable.Drawable;
+import android.os.Handler;
+import android.os.Message;
+import android.os.Handler.Callback;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.ImageView;
+import android.widget.LinearLayout;
+import android.widget.ProgressBar;
+
+/**
+ * Free for anyone to use, just say thanks and share :-)
+ * @author Blundell
+ */
+public class LoaderImageView extends LinearLayout {
+
+	private static final int COMPLETE = 0;
+	private static final int FAILED = 1;
+
+	private Context mContext;
+	private Drawable mDrawable;
+	private ProgressBar mSpinner;
+	private ImageView mImage;
+	
+	/**
+	 * This is used when creating the view in XML
+	 * To have an image load in XML use the tag 'image="http://developer.android.com/images/dialog_buttons.png"'
+	 * Replacing the url with your desired image
+	 * Once you have instantiated the XML view you can call
+	 * setImageDrawable(url) to change the image
+	 * @param context
+	 * @param attrSet
+	 */
+	public LoaderImageView(final Context context, final AttributeSet attrSet) {
+		super(context, attrSet);
+		final String url = attrSet.getAttributeValue(null, "image");
+		if (url != null) {
+			instantiate(context, url);
+		} else {
+			instantiate(context, null);
+		}
+	}
+	
+	/**
+	 * This is used when creating the view programatically
+	 * Once you have instantiated the view you can call
+	 * setImageDrawable(url) to change the image
+	 * @param context the Activity context
+	 * @param imageUrl the Image URL you wish to load
+	 */
+	public LoaderImageView(final Context context, final String imageUrl) {
+		super(context);
+		instantiate(context, imageUrl);
+	}
+	
+	/**
+     * This is used when creating the view programatically
+     * Once you have instantiated the view you can call
+     * setImageDrawable(url) to change the image
+     * @param context the Activity context
+     * @param imageUrl the Image URL you wish to load
+     */
+	public LoaderImageView(final Context context) {
+	    super(context);
+        instantiate(context, null);    
+    }
+
+	/**
+	 *  First time loading of the LoaderImageView
+	 *  Sets up the LayoutParams of the view, you can change these to
+	 *  get the required effects you want
+	 */
+	private void instantiate(final Context context, final String imageUrl) {
+		mContext = context;
+		
+		mImage = new ImageView(mContext);
+		mImage.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
+		
+		mSpinner = new ProgressBar(mContext);
+		mSpinner.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
+			
+		mSpinner.setIndeterminate(true);
+		
+		addView(mSpinner);
+		addView(mImage);
+		
+		if (imageUrl != null) {
+			setImageDrawable(imageUrl);
+		}
+	}
+
+	/**
+	 * Set's the view's drawable, this uses the internet to retrieve the image
+	 * don't forget to add the correct permissions to your manifest
+	 * @param imageUrl the url of the image you wish to load
+	 */
+	public void setImageDrawable(final String imageUrl) {
+		mDrawable = null;
+		mSpinner.setVisibility(View.VISIBLE);
+		mImage.setVisibility(View.GONE);
+		new Thread() {
+		    @Override
+			public void run() {
+				try {
+					mDrawable = getDrawableFromUrl(imageUrl);
+					imageLoadedHandler.sendEmptyMessage(COMPLETE);
+				} catch (MalformedURLException e) {
+					imageLoadedHandler.sendEmptyMessage(FAILED);
+				} catch (IOException e) {
+					imageLoadedHandler.sendEmptyMessage(FAILED);
+				}
+			};
+		}.start();
+	}
+	
+	/**
+	 * Callback that is received once the image has been downloaded
+	 */
+	private final Handler imageLoadedHandler = new Handler(new Callback() {
+		@Override
+		public boolean handleMessage(Message msg) {
+			switch (msg.what) {
+			case COMPLETE:
+				mImage.setImageDrawable(mDrawable);
+				mImage.setVisibility(View.VISIBLE);
+				mSpinner.setVisibility(View.GONE);
+				break;
+			case FAILED:
+			default:
+				// Could change image here to a 'failed' image
+				// otherwise will just keep on spinning
+				break;
+			}
+			return true;
+		}		
+	});
+
+	/**
+	 * Pass in an image url to get a drawable object
+	 * @return a drawable object
+	 * @throws IOException
+	 * @throws MalformedURLException
+	 */
+	private static Drawable getDrawableFromUrl(final String url) throws IOException, MalformedURLException {
+		return Drawable.createFromStream(((InputStream) new URL(url).getContent()), "name");
+	}
+	
+}