Treehouse Android Utilities

This repository holds helpful utility files for Treehouse Android projects. Included are a couple of helper classes that can be used to work with files in Android, like detecting a shake, resizing images, and converting to byte arrays.

Just download the files and add them to your own projects. FileHelper.java requires IOUtils from Apache Commons, which you can include with Gradle like this:

dependencies {
    compile 'commons-io:commons-io:2.5'
}

*Alternatively, download the required JAR here. Choose the latest zip file under "Binaries".

FileHelper.java

• getByteArrayFromFile(Context context, Uri uri): This method converts a file from a URI to a byte array. It accepts regular URIs as well as content URIs.
• reduceImageForUpload(byte[] imageData): This method is used to reduce a byte array for an image file to a smaller PNG.
• getFileName(Context context, Uri uri, String fileType): This method creates a file name using file type or the MIME type for both regular URIs and content URIs.

ImageResizer.java

• resizeImage(byte[] imageData, int targetWidth, int targetHeight): This resizes an image to a specified width and height.
• resizeImageMaintainAspectRatio(byte[] imageData, int shorterSideTarget): This version resizes an image based on a size for the shorter side of the images (it maintains the aspect ratio).
• getDimensions(byte[] imageData): This is a helper method to get the dimensions of an image.
• calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight): This is a helper method to calculate the appropriate sample size to use for resizing an image.

ShakeDetector.java

• Create a ShakeDetector object and implement the onShake() method from the OnShakeListener interface.