The first step to building an Android app is to learn the architecture and model of message passing. The following terms are necessary to understand the basic architecture of an Android app:
Activity: As the name indicates, an Activity is what a user does with the app. Every Activity is displayed to the user in a window. These can be full-screen windows, floating windows or windows nested inside another window. Intent: It represents the action to be performed. It acts as a bridge between activities. An Intent holds information about the action that needs to be performed by an Activity.
The final goal of the project is to capture image using camera app and pass the Intent to a new activity to handle the de-shredding operation. This deliverable was intended to help understand the structure of a typical android app which performs inter-activity communication. Figure 1 shows the user interface (UI) of the app.
The application works as follows: The user is initially shown a screen with the Capture Image button which when clicked, creates a camera intent which is passed to the camera app to aid in capturing the image.
Once the image is captured, it is saved to a location and this information is passed to the shred image activity. This is the crux of inter-activity communication. The split image activity picks up the information about the file location from the capture image activity and performs the necessary operations.