1. (a) What are the states of Activity? Explain with example. OR (b) What is the role of AVD in Android? How can we run a program if AVD is not working? 2. (a) How does DVM differ... 1. (a) What are the states of Activity? Explain with example. OR (b) What is the role of AVD in Android? How can we run a program if AVD is not working? 2. (a) How does DVM differ from JVM? Draw a diagram which shows how an APK is generated with the help of aapt. OR (b) What is final class? When do we need to use final class? Explain with an example. 3. (a) Design an App to take your name as an input, and display the number of vowels and consonants from that string with the help of TextView. Also write the XML code. OR (b) Write down the difference between implicit intent and explicit intent. Explain with examples when we need both types of intents. 4. (a) Explain with examples which app is better and why? Native app and Hybrid app. OR (b) Why are fragments required and how are they associated with Activity? 5. (a) Explain the architecture of Android. OR (b) What is SDK? Why is it required? What happens if SDK is missing in the system?
Understand the Problem
The question is asking about various aspects of Android programming, including concepts like Activity states, AVD roles, diagrams related to DVM and JVM, app design, intents, app types, fragments, architecture of Android, and SDK requirements.
Answer
1a. Activity states: onCreate(), onStart(), onResume(), onPause(), onStop(), onDestroy(). Example: Pause music in onPause(). 1b. AVD role: Emulator for testing. Alternatives: Physical device/Genymotion if AVD fails. 2a. DVM: Memory-optimized for Android. APK uses aapt. 2b. Final class: Unsubclassable, like Java String. 3a. App design: Input, vowel/consonant count via TextView. XML needed. 3b. Implicit vs. explicit intent: Implicit (action-based), explicit (component-based). 4a. Native vs. hybrid apps: Native (performance), hybrid (cross-platform). 4b. Fragments: Modular UI, used with activities. 5a. Android architecture: Linux, libraries, runtime, framework, apps. 5b. SDK: Developer tools. Essential for app development.
- (a) Activity states include: onCreate(), onStart(), onResume(), onPause(), onStop(), onDestroy(). Each state represents a phase in an activity's lifecycle. Example: A music player might pause playback in onPause().
(b) AVD (Android Virtual Device) is an emulator for testing Android applications. If AVD isn't working, you can use a physical device or a third-party emulator like Genymotion.
- (a) DVM (Dalvik Virtual Machine) is optimized for Android by using a different bytecode and structure to save battery and memory, unlike JVM. APK generation with aapt involves compiling code, packaging resources, and creating the APK.
(b) A final class cannot be subclassed. It's used when security or structure is necessary. Example: The String class in Java.
- (a) For the app design, capture input from the user, count and display vowels and consonants using TextView in the layout XML file.
(b) Implicit intents specify actions without specifying the app component, e.g., "share". Explicit intents determine the specific component to activate, e.g., "MainActivity".
- (a) Native apps are faster and provide better performance tailored to specific platforms, while hybrid apps are cross-platform and cost-effective. Use native when performance is critical.
(b) Fragments allow dynamic UI and reuse within activities. They represent parts of user interface in a modular format.
- (a) Android architecture includes: Linux kernel, hardware abstraction, native libraries, Android runtime, application framework, and applications.
(b) SDK (Software Development Kit) is essential for development of applications by providing needed tools. Without SDK, applications can't be built or tested.
Answer for screen readers
- (a) Activity states include: onCreate(), onStart(), onResume(), onPause(), onStop(), onDestroy(). Each state represents a phase in an activity's lifecycle. Example: A music player might pause playback in onPause().
(b) AVD (Android Virtual Device) is an emulator for testing Android applications. If AVD isn't working, you can use a physical device or a third-party emulator like Genymotion.
- (a) DVM (Dalvik Virtual Machine) is optimized for Android by using a different bytecode and structure to save battery and memory, unlike JVM. APK generation with aapt involves compiling code, packaging resources, and creating the APK.
(b) A final class cannot be subclassed. It's used when security or structure is necessary. Example: The String class in Java.
- (a) For the app design, capture input from the user, count and display vowels and consonants using TextView in the layout XML file.
(b) Implicit intents specify actions without specifying the app component, e.g., "share". Explicit intents determine the specific component to activate, e.g., "MainActivity".
- (a) Native apps are faster and provide better performance tailored to specific platforms, while hybrid apps are cross-platform and cost-effective. Use native when performance is critical.
(b) Fragments allow dynamic UI and reuse within activities. They represent parts of user interface in a modular format.
- (a) Android architecture includes: Linux kernel, hardware abstraction, native libraries, Android runtime, application framework, and applications.
(b) SDK (Software Development Kit) is essential for development of applications by providing needed tools. Without SDK, applications can't be built or tested.
More Information
Understanding Android concepts like AVD, activity lifecycle, and DVM helps in efficient app development.
Tips
Confusion between implicit and explicit intents can lead to incorrect component activation. Remember implicit uses actions, explicit specifies components.
Sources
- Introduction to activities - Android Developers - developer.android.com
- The activity lifecycle | Android Developers - developer.android.com
- Dalvik Virtual Machine - Javatpoint - javatpoint.com
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