incubator-callback-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Lucas Emanuel Martins Farias (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CB-14) CameraLauncher Plugin enhancement for loading big image files to avoid OutOfMemory exceptions
Date Thu, 23 Feb 2012 20:28:48 GMT

    [ https://issues.apache.org/jira/browse/CB-14?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13215021#comment-13215021
] 

Lucas Emanuel Martins Farias commented on CB-14:
------------------------------------------------

This problem occurs when your application is sent to background and the camera activity is
in the foreground. We discovered that our application is being killed because camera takes
too much memory and the garbage colector release memory killing background apps. This problem
occurs with native Android apps too, so you have to build your own camera app. We resolved
this problem creating our camera app described here: http://developer.android.com/guide/topics/media/camera.html#custom-camera

So we created a Camera Activity that is called by a plugin and the problem donĀ“t occured
anymore. This way, you app is in foreground preventing the GC to kill it.


                
> CameraLauncher Plugin enhancement for loading big image files to avoid OutOfMemory exceptions
> ---------------------------------------------------------------------------------------------
>
>                 Key: CB-14
>                 URL: https://issues.apache.org/jira/browse/CB-14
>             Project: Apache Callback
>          Issue Type: Improvement
>          Components: Android
>    Affects Versions: 1.1.0
>         Environment: Android SDK: 2.x & above
> JDK: 1.6
> Eclipse: Helios
>            Reporter: Bright Zheng
>            Priority: Critical
>              Labels: CameraLauncher, OutOfMemory, decodeStream
>             Fix For: 2.0.0
>
>
> Currently the CameraLauncher plugin of Phonegap (or Apache Callback) is using Android
default API for stream decoding.
> It will be very easy to get crash by throwing out the OutOfMemory exceptions while loading
bigger image files.
> So I add a new method called safeDecodeStream for better stream decoding.
> {code:title=safeDecodeStream method|borderStyle=solid}
>     /**
>      * A safer decodeStream method
>      * rather than the one of {@link BitmapFactory}
>      * which will be easy to get OutOfMemory Exception
>      * while loading a big image file.
>      * 
>      * @param uri
>      * @param width
>      * @param height
>      * @return
>      * @throws FileNotFoundException
>      */
>     protected Bitmap safeDecodeStream(Uri uri, int width, int height)
>     throws FileNotFoundException{
> 		int scale = 1;
> 		BitmapFactory.Options options = new BitmapFactory.Options();
> 		android.content.ContentResolver resolver = this.ctx.getContentResolver();
> 		
> 		if(width>0 || height>0){
> 			// Decode image size without loading all data into memory
> 			options.inJustDecodeBounds = true;
> 			BitmapFactory.decodeStream(
> 					new BufferedInputStream(resolver.openInputStream(uri), 16*1024),
> 					null,
> 					options);
> 			
> 			int w = options.outWidth;
> 			int h = options.outHeight;
> 			while (true) {
> 				if ((width>0 && w/2 < width)
> 						|| (height>0 && h/2 < height)){
> 					break;
> 				}
> 				w /= 2;
> 				h /= 2;
> 				scale *= 2;
> 			}
> 		}
> 		// Decode with inSampleSize option
> 		options.inJustDecodeBounds = false;
> 		options.inSampleSize = scale;
> 		return BitmapFactory.decodeStream(
> 				new BufferedInputStream(resolver.openInputStream(uri), 16*1024), 
> 				null, 
> 				options);
> 	}  
> {code} 
> And then change all the codes which are invoking the Android decodeStream API directly
to this method.
> e.g.
> {code:title=usage example|borderStyle=solid}
> //Updated by Bright for safer decodeStream
> //android.content.ContentResolver resolver = this.ctx.getContentResolver();
> //bitmap = android.graphics.BitmapFactory.decodeStream(resolver.openInputStream(uri));
> bitmap = safeDecodeStream(uri, this.targetWidth, this.targetHeight);
> {code} 

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

       

Mime
View raw message