This is a simple app which contains two functions:
- Allow a user to select an image or images from their gallery or take an image with their camera
- Upload image(s) to a remote server
- Rate the image(s) as being food or not food
- Allow the user to view previously uploaded images and their ratings
This app needs only four permissions: read, write, camera and internet. Read is used to allow the user to select an image from their device, write is used to save an image to their device, camera is used to take a new image with the user's camera, and internet is required to communicate with the remote server.
Development was done against API Level 28 / Android 9.0. It may, but it is not guaranteed to work with any lower version.
Running the APK (it is in the root github directory) should be as easy as loading it onto your device and installing. Apps from unknown sources must be enabled. This app is not available on the app store, it would simply generate too many sales.
This project was written in Kotlin, as it is now Android's first class language. All developers were already familiar with Java. Android Studio was the IDE used. Testing was done on a Huawei Nexus 6P, Samsung Galaxy Note 8, and various emulated devices.
The app is implemented with several classes:
This is the starting activity, and the home screen for the app. From here, the user can open new activities to take a picture, select a picture from their gallery, or view previously uploaded images.
There is no activity for camera or gallery, since those function are handled by the user's default apps. Once they take or select image(s), they are taken here. This screen consists of only an upload button or a button to go back to the previous action (whether that be camera or gallery).
The results activity opens after the user's image(s) has been classified by the server and the results are received by the app.
The history activity shows previously classified images and their ratings. When the activity is opened, a call is made to the server to return image thumbnails and classification data. This data is then displayed for the user.
On this activity the user can see statistics related to images uploaded over time, in relation to how many were food or not food, and how many total.
In Android, network operations are not allowed to run on the main UI thread. For network operations, it is necessary to create a service which can be run asynchronously. For uploading images to the server or pulling down images from the server, we have two separate services.
The following resources were used for this project: