Android Studio Sound Effects Quiz & Flashcards

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Questions and Answers

What is the correct way to refer to an audio file in Java code?

R.raw.filename.mp3

filename.R.raw.audio

audio.filename.R.raw

R.raw.filename (correct)

What is the primary purpose of the MediaPlayer class in Android?

To display images on the screen

To manage multiple activities

To handle user input events

To play audio and video files (correct)

What happens when an activity A launches another activity B in response to an event?

Activity A is terminated

Activity B is launched without any data

Activity B is launched with data from Activity A (correct)

Activity A waits for Activity B to finish

What is the purpose of the seekTo method in the MediaPlayer class?

To move to a specific position in a file Signup and view all the answers

What is the correct format for sound filenames in Android?

Filenames with only letters and numbers Signup and view all the answers

What happens when an activity is finished in Android?

It is terminated and its resources are released Signup and view all the answers

What is the purpose of passing a unique ID number to startActivityForResult?

To represent the action being performed Signup and view all the answers

What happens when startActivityForResult is called?

The method returns immediately Signup and view all the answers

What is the purpose of the onActivityResult method?

To receive a result from a called activity Signup and view all the answers

How does an activity send a result back to the calling activity?

Using the setResult and finish methods Signup and view all the answers

What is the purpose of the Intent in the onActivityResult method?

To store extra data to be sent back Signup and view all the answers

What happens when the setResult and finish methods are called?

The activity is ended and the result is sent back Signup and view all the answers

What is the purpose of an intent in Android?

To pass data between activities as key-value pairs Signup and view all the answers

What happens when you create a new activity in Android Studio?

All of the above Signup and view all the answers

What is the purpose of AndroidManifest.xml?

To declare the activities in an app Signup and view all the answers

How do you extract extra data from an intent in the second activity?

By calling getIntent and then getExtra Signup and view all the answers

What is the purpose of the startActivity method?

To start the next activity with the given intent Signup and view all the answers

What is the difference between an intent and an activity?

An intent is a way to pass data between activities, while an activity is a separate screen Signup and view all the answers

What is the purpose of putExtra method?

To store data as key-value pairs in an intent Signup and view all the answers

What happens if you don't add an activity to the AndroidManifest.xml?

The app will not allow the activity to run Signup and view all the answers

Study Notes

Playing Sound Effects

Place sound files (e.g., .WAV, .MP3) in the project folder app/src/main/res/raw.
In Java code, refer to the audio file as R.raw.filename (without the extension).
Use simple file names with only letters and numbers.

Loading and Playing Sound Clips

Use Android's MediaPlayer class to load and play sound clips.
Methods available:
- create(): creates a MediaPlayer object.
- start(): starts playing the sound clip.
- Others: stop(), pause(), isLooping(), isPlaying(), getCurrentPosition(), release(), seekTo(), setDataSource(), setLooping().

Multiple Activities

Many apps have multiple activities, e.g., an address book app with a list of contacts and a separate activity for viewing details.
One activity can launch another activity in response to an event and pass data to it.
The second activity can send data back to the first activity when it's done.

Adding an Activity

In Android Studio, right-click "app" and select "New" > "Activity" to create a new activity.
This creates a new .xml file in res/layouts and a new .java class in src/java, and adds information to AndroidManifest.xml about the activity.

Activities in Manifest

Every activity has an entry in AndroidManifest.xml, added automatically by Android Studio.

Intents

An Intent is a bridge between activities, allowing one activity to invoke another.
Intents can store extra data as "parameters" to pass to the second activity.
The second activity can return information back to the caller if needed.

Creating an Intent

Create an Intent object and call startActivity() with it to launch another activity.
Use putExtra() to pass parameters to the second activity.

Extracting Extra Data

In the second activity, use getIntent() to access the Intent that spawned it.
Use methods like getExtra(), getIntExtra(), getStringExtra(), etc. to extract data stored in the intent.

Waiting for a Result

Use startActivityForResult() instead of startActivity() to wait for a result from the called activity.
Pass a unique ID number to represent the action being performed.
Write an onActivityResult() method to handle the result.

Sending Back a Result

In the second activity, create an Intent to send data back.
Use setResult() and finish() to end the called activity.

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Description

Learn how to play sound effects in an Android app, including loading and managing audio files using the MediaPlayer class. Understand how to reference sound files in Java code.