Android Intents and Services Quiz

Intents and Services

• Intents are mechanisms for one app component to request another component to perform an action.
• Two types of Intents: Explicit and Implicit.
• Explicit Intents: Specify the exact component to be launched and provide the required data.
• Implicit Intents: Indicate the general action to be performed, without specifying the exact component; the system selects a suitable component to handle the request.
• Example explicit intent: Login and Home screen examples.
• Example implicit intent: A URL opener activity example.
• Implicit intents can use actions such as viewing data, editing data, sending data to another app, initiating a phone call, performing a web search, etc

Activities, Services, and Broadcast Receivers

• Activities are app components that represent a single screen in a user interface.
• Services run background tasks and perform long-running operations, untethered from the user interface.
• Broadcast Receivers react to system-level or application-level events, enabling apps to respond to events even when backgrounded or in the sleep mode.

Android Activity Lifecycle

• Activities are created, started, paused, stopped, and destroyed.
• onCreate(): Called when an activity is first created.
• onStart(): Called when the activity becomes visible to the user.
• onResume(): Called when the activity is in focus.
• onPause(): Called when the activity goes into the background.
• onStop(): Called when the activity is no longer visible.
• onDestroy(): Called when the activity is being destroyed.
• onRestart(): Called immediately after the onStop() method.

Service Lifecycle

• Services can run in the foreground or background, depending on the operation they perform.
• Services have different ways of being started, and different ways of being stopped.
• Unbound service lifecycle: A service that can be started with startService(). It is an independent component of the app. It doesn't interact with other app components.
• Bound service lifecycle: A service where clients can explicitly bind to the service and communicate with it using Interface and create a connection.

Intents Code Example

• Includes examples for initiating Activities using Intents.
• Code examples demonstrate the steps involved in creating an Intent, specifying the destination Activity, and initiating the transition using startActivity.
• Includes examples for passing data from one Activity to another using putExtra.
• Provides basic structure of the code demonstrating the use of startActivity.

Login-Home Example

• Design example involving two Activities: Login and Home.
• Login Activity contains fields for username and password.
• Home Activity displays a welcome message to the user who logged in.

The Login Activity Layout

• Describes the visual elements.
• Shows the components used in the layout, such as a TextView, two EditText fields, and a Button.
• Explains that clicking the Login button triggers the Activity transition to the Home Activity.

The Home Activity Layout

• Describes the visual elements.
• Shows the components used in the layout, such as a TextView used to display a welcome message.
• Explains how the Home Activity receives values from the Login Activity.

Implicit Intents - List of Actions (Different Actions)

• Describes specific actions that can be executed through implicit intents, such as displaying data, editing data, performing web searches, sending data, initiating calls, etc.
• Includes types of actions: displaying data, editing data, sharing data between applications, making a phone-call, etc

Implicit Intents (Additional Actions)

• Provides details about implicit intents for actions such as picking content, capturing images and videos, opening files and documents, installing packages, and deleting data.

A URL Opener Example

• Explains how to create an Intent to manage a URL, specifying the action (VIEW) and the destination using a URI.

The MainActivity Layout

• Describes the visual layout design of the MainActivity.
• Shows Textview, button, and EditText features involved in the layout.
• Explains the actions triggered when the button is clicked, such as launching a specific application with the URL.

The MainActivity

• Provides the main activity class code structure, imports and methods.

Music Player Service - Information

• Describes the process of integrating music files into the project. This includes instructions for adding a music (.mp3) file to the raw folder within your Android project.

Create the Activity

• Explains how to create an Activity with buttons that will start and stop a service.
• Suggests how the layout of the activity should be designed.

The MainActivity Class (Rough)

• Shows the structure of the main activity class, including imports, and declarations of components such as start and stop buttons.

The Click Method

• Describes the onClick method responsible for reacting to clicks on the start and stop buttons.
• Explains how the startService and stopService methods are invoked for initiating service operations.

The Service Class (Rough)

• Shows the overall structure of the service class, such as a MediaPlayer component, and specific methods.

Use the MediaPlayer Object

• Details on using the MediaPlayer object for playing audio files, including the methods for starting, pausing, and stopping the music as well as enabling repetition (setLooping).

The Service Methods (Details)

• Describes the specific functionality of different methods within the Service class, including the onBind method.

onStartCommand() Method

• Explains the important aspects of the onStartCommand() method:
• How it's called when another component triggers the start of a service, and the different ways to respond (START_STICKY etc.)
• Describes how the method is used in starting the music player service.

onDestroy() Method

• Explains the mechanism of the onDestory() method, which is intended to be used in freeing up resources from the service, like stopping the music, freeing up memory, etc.
• Emphasizes the importance of calling player.stop() when the service is no longer required.

Finally, Check the AndroidManifest.xml File for Service

• Provides instructions to ensure that your service is correctly declared in your AndroidManifest.xml file.

Homework

• Provides homework exercises to extend existing application functionalities, specifically modifying the Media Player service, allowing users to select and play audio files.

Test your knowledge on Android Intents and Services! This quiz covers the difference between explicit and implicit intents, as well as the roles of activities, services, and broadcast receivers in app development. Enhance your understanding of these key components of Android programming.