Top 10 Android Developer Interview Questions

Any kind of configuration change in Android devices tends to recreate the whole activity of the application. It means the data will be lost if it has not been saved and restored properly from the activity which was destroyed. To avoid these issues, it is recommended to store all UI data in the ViewModel instead of an activity. Developing an android application involves several processes that happen sequentially.

With the use of inheritance the information is made manageable in a hierarchical order. Yes, an interface can implement another interface , but it needs to use extends, rather than implements keyword. And while you can not remove methods from parent interface, you can add new ones freely to your sub-interface. OnSavedInstanceState() – This method is used to store data before pausing the activity.

Situational interview questions

For example, using your Android-powered phone as a Wi-Fi Hotspot, you can use your laptop to connect to the Internet using that access point. You then drag it downwards to the lower part of the screen where a remove button appears. It is modular in a sense that you can move around or combine with other fragments in a single activity. Intents displays notification messages to the user from within the Android enabled device. It can be used to alert the user of a particular state that occurred.

It is used in Android Applications when an item needs to be created just once and used across the board. The main reason for this is that repeatedly creating these objects, uses up system resources. The identical object should therefore only be created once and used repeatedly. It is utilized in situations where we only require a single instance of the class, such as with network services, databases, etc.

How would you implement swipe animation in Android

Components that provide users with screens on which they can interact with objects and perform actions. Objects that initiate actions from other app components, either within your program or through another piece of software on the device . Google has changed the lives of everyone by launching a product that improves the mobile experience for everyone.

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Briefly describe some ways that you can optimize View usage

One technique is to create a child thread to prevent the Android system from concluding a code that has been unresponsive for a long period of time. Most of the actual workings of the codes can be placed within the child thread to ensure that the main thread runs with minimal unresponsive time. Activity is the equivalent of a Frame/Window in GUI toolkits.

Advanced Android interview questions are an opportunity to showcase your advanced knowledge, and also your leadership skills and creativity. In this case, lay out some testing fundamentals to start , and then shift into a discussion of your preferred testing approaches to demonstrate your problem-solving capabilities. A project under Android development, upon compilation, becomes an .apk file. This apk file format is actually made up of the AndroidManifest.xml file, application code, resource files, and other related files.

Q7. What is the life cycle of android activity?

The server manages communication between the client and the ADB daemon running on an emulator or device. You can invoke a client from a shell by issuing an ADB command. Fragment is a modular section of an activity, with its own lifecycle and input events, and which can be added or removed at will. Broadcast receiver is used by the application whenever they need to perform the execution based on system events. For background task-intensive apps, you can alleviate pressure from the UI thread by using the IntentService.

• AAPT – It is a build tool that gives the ability to developers to view, create, and update ZIP-compatible archives .
• When default resources, which contain default strings and files, are not present, an error will occur and the app will not run.
• Instead of creating new view for each new row, an old view is recycled and reused by binding new data to it.
• A thread is a single sequential flow of control within a program.
• An application that runs smoothly on one version of the Android OS might crash on another Android OS.

Activity in java is a single screen that represents GUI with which users can interact in order to do something like dial the phone, view email, etc. Content providers − This will share the data between various applications. Explain in detail about the important file and folders used when you create a new Android application. It rarely happens, but sometimes, there are projects that I could not meet certain deadlines. That’s why I strongly believe that proper planning and documentation are very important.

What’s Android SDK and its Components?

A way around repeated use of findViewById() is to use the “view holder” design pattern. Normal — A lower-risk permission that gives requesting applications access to isolated application-level features, with minimal risk to other applications, the system, or the user. The system automatically grants this type of permission to a requesting application at installation, without asking for the user’s explicit approval. Activities are basically containers or windows to the user interface.

Thread should be used to separate long running operations from main thread so that performance is improved. But it can’t be cancelled elegantly and it can’t handle https://wizardsdev.com/en/vacancy/android-developer/ configuration changes of Android. The onStart() method is called whenever the Activity becomes visible to the user, typically after onCreate() or onRestart().