Hi :) I'm trying to write an android application that downloads a bunch of images and afterwads displays them in a gallery. I managed to download the images (i did download them do the data/data/project directory - not sure if that's right) but now i can't access them (i tried using the setImageURI method of the imageView to display the image after I've created an Uri instance via Uri.Builder().appendPath("data/data/project/file.jpg").build() but it was to no avail). I'm new to android developing so any help will be greatly appreciated. Thanks!
I started writing up an example, but decided that it was a waste of time since the net is littered with better examples then I could create.
At a high level, you'll need to do this:
Get 1..n File objects
Load Bitmaps from these objects using BitmapFactory
Load these decoded bitmaps into a ImageView
The typical mechanism for viewing a set of resources like this is the Adapter pattern. As I mentioned, there is a good example here which also encompasses the use of AsyncTask and some other patterns typical of Android programming which you should become familiar with. Review that and see if you have further questions.
Try:
Uri uri = Uri.parse("file:///data/data/project/file.jpg");
image.setImageURI(uri);
Related
I would like to ask advise if displaying pdf inside gridview instead of image is possible. I have tried to display list of websites in gridview using webview. Now, I want to make it a list of pdf files inside gridview. Normally same with if you open your folder in your linux laptop and have the thumbnails of your pdf, things like that. I want to achieve that in my application. I would really appreciate any of your advice, no codes needed cause i will handle it my self. I just want to have some theories. thanks and HAPPY NEW YEAR GUYS
I think what you're going to have to is convert the pdf's into a bitmap first, then load into an ImageView, check out this post and also look into other pdf rendering libraries for Android.
I have 3 sets of 50 images and I have to create the animations for each set of images in Android application. I am able to create a simple application which animate first set of 50 images using the below method,
Added Animation-list xml in drawable folder and called it using frameAnimation.start().
This method didn't work until I kept the following "android:largeHeap="true" in manifest file.
I am not sure whether this is the good way to animate the images (if we have more number of images and each image of more size like 60 KB. Image is JPG format) or not
I browsed and I found that, if we are able to clear the memory and if we are able to maintain less number of images in memory, then our application will work very fine. So I want to know how to clear the memory?
Please let me know do I need to follow different method to animate the images other than I explained above, so that I can clear the memory.
Thanks for your help.
After looking into several posts and doing much research, I finally ended up modifying the images in Imageview programmatically to simulate frame animation. That way I am just maintaining three images in cache at any point of time (previous, current and next one). I hope that this will be useful to others.
It is not a good thing to process a large amount of images in a frame like manner in Android itself as it will trigger the dreaded "Out of Memory" exception.
Clearing the memory itself is not possible. The best fix for this is proper bitmap handling of the app.
I'm not sure but you might want to check on PhoneGap.
Its an HTML5 Engine that we used before to create a game.
By drawing into the canvas itself, we've recreated frame animation with it. It just requires WebDev skills though.
I'm going to be making a wallpaper app but need some guidance on how I am going to be able to store, retrieve and view the wallpapers.
Will I need to make use of ImageView so I will be able to display the images?
I'm going to need some sort of database/website to store all of the wallpapers on. What would be the best thing to do, use a database or a website?
How would I go about retrieving the wallpapers from my chosen source?
Any help/advice would be appreciated, thanks.
A common practice is to use an rss feed of images. Then, just hook up your app to the rss feed and have it check for updates periodically.
Here is a reference on reading xml (rss) in Android:
http://www.ibm.com/developerworks/opensource/library/x-android/index.html
Good luck.
you can try aquery android library for lazy loading image. this library store images in cache memory so you not need to store it externally also it will take some time for first time loading image from web but once it load in your application then it will automatically store in cache so second time take very less time to display also its less time consuming then other lazzy loading methods..below code may help you.....
AQuery aq = new AQuery(mContext);
aq.id(R.id.image1).image("http://data.whicdn.com/images/63995806/original.jpg");
You can download library from from this link
Personally I would use a database. But the easiest option would be to use the 'res/drawable' folder in android I guess.
If you stored them on the internet and haven't got connectivity, you can't get your images, so users won't necessarily like this.
To get at them from a database you'll likely have to know some SQL or know someone who knows a bit of SQL. The advantage of storing them in a database would be that it's one neat package and it is portable.
Don't worry about using ImageView it, you just need to get the image from the source (database /filesystem etc..) and give it to the imageView
I was thinking about starting a gallery app with the ability to search/filter images based on tags. My question:
I want to update the images often so... should I host the images on a webserver and host a XML file the app can call with image paths thumbnail path and tags name. That way I can load the thumbs to save bandwidth until they click and then load the main image.
XML Below:
<image>
<title>My Family</title>
<tags>family,vacation,grandpa</tags>
<thumb>myimage_thm.jpg</thumb>
<full_path>myimage.jpg</full_path>
</image>
And then use the built in android gallery?
Does this sound like the most efficient way start my project? Any thoughts would be much appreciated.
Use json instead of xml format to transfer your updates.
Implement REST interface to post updates to your server.
If you are going to download these thumbnails use Async threads to download these images. Take a look at droidfu (http://brainflush.wordpress.com/2009/11/23/droid-fu-part-2-webimageview-and-webgalleryadapter/)
Also look at the app photostream by romain guy. This should give you a good idea on how to implement your gallery app.
I've got an app where the main viewing area is a WebView.
It's a service where a user can also upload a photo. However, with the WebView, and photo uploads, I'm getting some OutOfMemoryErrors.
Usually all it takes is a page loaded in the WebView, and then simply trying to open an image with something like this:
Bitmap bmp = BitmapFactory.decodeFile(path);
The only reason I need to open the file at all is so that I can scale it down so that it fits in a max width/max height dimensions before uploading it.
I've even tried opening it in a sampled fashion, similar to what's mentioned here:
Strange out of memory issue while loading an image to a Bitmap object
However, with a complex webpage loaded in the WebView, I still get OutOfMemoryError when trying to open the image.
Is there a way to scale it, maybe using another process or something, that's more memory efficient?
I'm glad you asked, I was about to investigate this for my own project.
It looks like BitmapFactory.Options is your friend here, specifically BitmapFactory.Options.inSampleSize enter link description here. You can use BitmapFactory.decodeStream to get the image dimensions without creating a Bitmap.
Googling revealed the com.bristle.javalib.awt ImgUtil classes; these appear to be open source (don't know the license), and are AWT based, so may work on Android. The interesting method is ImgUtil.scalueImageToOutputStreamAsJPEG, which works with InputSteam/OutputStream, so may be memory efficient.
UPDATE
An alternative is to write a JNI wrapper around /system/lib/libjpeg.so, which appears to be standard on Android devices. This library works with scanlines, so can be memory friendly. Another plus is that using JNI should be faster than pure java.
Hope this helps,
Phil Lello
I had a similar problem and found a workable solution using BitmapFactory.Option.inScale. You can find details here: How do I scale a streaming bitmap in-place without reading the whole image first?