Category «Android Advanced Concepts»

Dimming the System Bars in Android

The system bars are screen areas dedicated to the display of notifications, communication of device status, and device navigation. Typically the system bars (which consist of the status and navigation bars, as shown in figure 1) are displayed concurrently with your app. Apps that display immersive content, such as movies or images, can temporarily dim …

Accessibility Testing Checklist in Android

Testing is an important part of making your application accessible to users with varying abilities. Following design and development guidelines for accessibility are important steps toward that goal, but testing for accessibility can uncover problems with user interaction that are not obvious during design and development. This accessibility testing checklist guides you through the important …

Developing Accessible Applications in Android

Android has several accessibility-focused features baked into the platform, which make it easy to optimize your application for those with visual or physical disabilities. However, it’s not always obvious what the correct optimizations are, or the easiest way to leverage the framework toward this purpose. This lesson shows you how to implement the strategies and …

Tracking Movement in Android

This lesson describes how to track movement in touch events. A new onTouchEvent() is triggered with an ACTION_MOVE event whenever the current touch contact position, pressure, or size changes. As described in Detecting Common Gestures, all of these events are recorded in the MotionEvent parameter of onTouchEvent(). Because finger-based touch isn’t always the most precise …

Detecting Common Gestures in Anroid

A “touch gesture” occurs when a user places one or more fingers on the touch screen, and your application interprets that pattern of touches as a particular gesture. There are correspondingly two phases to gesture detection: Gathering data about touch events. Interpreting the data to see if it meets the criteria for any of the …

Maintaining Compatibility in Android

Some material design features like the material theme and custom activity transitions are only available on Android 5.0 (API level 21) and above. However, you can design your apps to make use of these features when running on devices that support material design and still be compatible with devices running previous releases of Android. Define …