Saturday, January 9, 2010

My First Android Application - Device photos

This tutorial shows you the code to get metadata about the images on your Android phone and also how to set up your development environment to test the code locally using the Emulator. This tutorial assumes that you have properly installed version 1.5 of the Android SDK, are using Eclipse to develop Android applications, and have installed the ADT for Eclipse. Also, these instructions were written for Mac users. I will link to instructions for Linux users whenever I can. PC users - you're on your own.

Creating an SD Card

First and foremost: you should know that the photos you take with your Android phone are stored on the SD Card. The images are stored in the directory: /sdcard/dcim/Camera. We're going to mimic the SD Card locally. The local SD Card is actually a disk image. No SD Card disk image comes with Android SDK, so we need to create one.

To create the SD Card image, navigate to your /tools directory using the Terminal. Depending on your PATH variable, you might have to add the tools directory to your PATH. This will allow you run the files in the tools directory. In my case, I ran the command:

export PATH=$PATH:/Users/kat/JavaLibraries/android1.5/tools

Next, we need to actually create a disk image of the SD Card. Run the command:

mksdcard 1024M .img

In my case, I ran the command:

mksdcard 1024M myimage.img

If you look in the tools directory, you should see a new file in there called 'myimage.img' (or whatever you decided to call it). Please make sure you use the .img extension, since this will help you later when mounting the image. Which brings me to my next topic: mounting the image. :)

Adding Folders/Images to the SD Card Image

In order to create folders and upload files to our new image, I found it easiest to use the Disk Utility on my mac to mount the 'myimage.img' file. If you're using Linux, try the directions here.

Start the Disk Utility application (it's in the System Utilities folder in the Applications directory). Once started, Select File > Open Disk Image... Navigate to your newly created disk image in the tools directory. Select OK. You should see the disk image in the list. If it's not already opened, right click on the image and select "Open". The SDCARD should appear under it. Right-click on the SDCARD and select "Reveal in Finder". Double-click on the "sdcard" folder in the Finder window. Once in this folder, you can create new folders and copy and paste images within the folders. In our case, we want to create the following directory structure under sdcard:


Within the Camera folder, place some images. JPGs should work fine. Not too sure about any other formats, I haven't tried them yet.

Finally, we need to unmount the disk image. Right-click on the SDCARD in the Disk Utility window. Select 'unmount sdcard'. Then eject the disk image by right-clicking on it and select "eject".

Perfect, we're almost done! Not too difficult, right?

Setting up Eclipse to Recognize the New SD Card Image

Next step is to set up Eclipse to run our new sdcard image with the Emulator instead of the non-existent one it uses by default. There are 2 possible places to make this change in Eclipse. I found one doesn't work at all, the other does. I'm going to include both places, though, just in case.

The one that didn't seem to work - In Eclipse, click on the Eclipse Menu > Preference. Expand the Android menu, select Launch. In the Default emulator options, enter

-sdcard /[path]/[imagename].img

In my case, I entered:

-sdcard /Users/kat/JavaLibraries/android1.5/tools/myimage.img

The one that did work - In Eclipse, create an Android project titled 'PhotoFun' (or whatever). Right click on the Project, select Run As > Open Run Dialog... In the Run Dialog Box, under the "Target" tab, enter the same text as above (-sdcard /[path]/[imagename].img) into the Additional Emulator Command Line Options box.


If you didn't create the Android Project as I mentioned in Step 2 directly above, please do so now. Call the Project 'PhotoFun' or whatever you want.

First, open the res > layout > main.xml file. Replace the TextView element with the following:


Next, open the main class (src > Add the following lines to the onCreate method after setContentView(R.layout.main);

TextView imageData = (TextView) findViewById(;

String[] s = {MediaStore.Images.Media.TITLE,
MediaStore.Images.Media.DATE_MODIFIED, MediaStore.Images.Media.SIZE};
Cursor cursor = managedQuery(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, s, null,null,null);

StringBuilder string = new StringBuilder();
while(cursor.moveToNext()) {
String theFile =
"Title: " + cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.TITLE))
+ "\n" +
"Date Mod: " +
+ "\n" +
"Size: " +

string.append(theFile + "\n\n");


Now run your application as a Android app. Once the Emulator is loaded you should see a list of all the photos in the /sdcard/dcim/Camera directory! Awesome!

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