Android User Interface Controls Quiz

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Questions and Answers

What method in Android is called when a View is touched?

onTouch()

onLongClick()

onClick()

onTouchEvent() (correct)

Which listener is used to detect click style events in Android?

onLongClickListener

onClicklistener

onTouchListener

onClickListener (correct)

What is the purpose of the onLongClickListener in Android?

To handle short click events

To detect long touches on a View (correct)

To handle multiple touch events

To manage asynchronous tasks

How can a callback method for capturing click events be set for a Button in Android XML?

By adding a line to the declaration of the Button view Signup and view all the answers

Which interface in Android contains a single callback method for event handling?

OnClickListener Signup and view all the answers

What information is passed as arguments to a callback method?

View, KeyCode, and KeyEvent object Signup and view all the answers

What does a callback method returning true indicate?

The event was consumed by the method Signup and view all the answers

In Android, what happens if a callback method returns false?

The event is passed to the next registered listener Signup and view all the answers

Which callback method is called when a new key event occurs?

onKeyDown(int, KeyEvent) Signup and view all the answers

What type of event triggers the callback method `onTrackballEvent`?

Trackball motion event Signup and view all the answers

What callback method is used to detect any form of contact with the touch screen, including individual or multiple touches and gesture motions?

onTouchListener Signup and view all the answers

Which event listener is triggered when a key on a device is pressed while a view has focus?

onKeyListener Signup and view all the answers

What does the onFocusChangeListener detect in Android event handling?

Focus moving away from a view Signup and view all the answers

Which callback method is used to listen for the creation of a context menu as the result of a long click?

onCreateContextMenuListener Signup and view all the answers

In Android, what does the onLongClick() callback method receive as an argument?

The view that received the event Signup and view all the answers

What Android control type is used for a drop-down list that allows users to select one value from a set?

Spinner Signup and view all the answers

Which Android control type is an on/off switch that can be toggled by the user?

Toggle button Signup and view all the answers

For creating custom components in Android, what is the basic approach mentioned in the text?

Extend an existing View class and override superclass methods Signup and view all the answers

Which Android control type is used for cases where only one option can be selected in a group, unlike checkboxes?

Radio button Signup and view all the answers

What is the purpose of a Button control in Android?

To perform an action when pressed by the user Signup and view all the answers

What method allows a parent View to indicate that it should not intercept touch events?

ViewParent.requestDisallowInterceptTouchEvent(boolean) Signup and view all the answers

Which method allows Activity to intercept all touch events before they are dispatched to the window?

Activity.dispatchTouchEvent(MotionEvent) Signup and view all the answers

What type of state is the appearance of the user interface before being committed to the app’s data model?

Dynamic state Signup and view all the answers

In which method can an activity handle a configuration change without restarting?

onConfigurationChanged() Signup and view all the answers

Which method allows a ViewGroup to watch events as they are dispatched to child Views?

ViewGroup.onInterceptTouchEvent(MotionEvent) Signup and view all the answers

What is the purpose of an event listener in Android?

To generate events in response to external actions Signup and view all the answers

How are events stored in the Android framework?

First-in, first-out (FIFO) basis Signup and view all the answers

What is the role of a callback method in Android event handling?

To respond to events of a particular type Signup and view all the answers

Which class in Android contains event listener interfaces?

View Signup and view all the answers

Why is it necessary for a view to register an event listener in Android?

To respond to user interactions with the UI Signup and view all the answers

What is the benefit of using ConstraintLayout in Android?

Improved layout performance Signup and view all the answers

Which tool in Android Studio is tightly integrated with ConstraintLayout?

Layout Editor tool Signup and view all the answers

In a dynamic layout scenario, what is used to populate the layout with views at runtime?

AdapterView Signup and view all the answers

What role does an Adapter play in Android layouts backed by it?

Binds data to the layout Signup and view all the answers

Which components are considered input controls in Android apps?

Buttons, text fields, seek bars Signup and view all the answers

How is an input control usually added to an Android XML layout?

By adding an XML element Signup and view all the answers

Study Notes

Touch Events

onTouchEvent() is the method called when a View is touched.
OnClickListener is used to detect click-style events.
onLongClickListener detects long presses.
A callback method for click events can be set in XML for a Button using android:onClick attribute.

Event Handling Interfaces and Callbacks

View.OnClickListener interface contains a single callback method for event handling.
Callback methods receive arguments such as View.
Returning true from a callback method indicates that the event has been handled.
If a callback method returns false, the event is passed to the next listener in the chain.

Key Events and Touchscreen Interactions

onKeyDown and onKeyUp are called when a new key event occurs.
onTrackballEvent is triggered by a trackball event.
onTouchEvent detects all forms of touch screen contact, including single and multiple touches and gestures.

onFocusChangeListener detects focus changes for a View.
onCreateContextMenu is called when a long click creates a context menu.
onLongClick() receives a View argument.

Android Controls

Spinner is a drop-down list for selecting one value.
Switch is an on/off toggle.
Creating custom components often involves extending View class.
RadioGroup is used for groups where only one option can be selected.
Button triggers an action when clicked.

ViewGroup Events and State Management

requestDisallowInterceptTouchEvent allows a parent View to prevent intercepting touch events.
dispatchTouchEvent lets an Activity intercept all touch events before they reach the window.
The appearance of the user interface before being committed to the data model is called the transient state.
onConfigurationChanged handles configuration changes without restarting the activity.
onInterceptTouchEvent allows a ViewGroup to observe touch events dispatched to child views.

Event Listener Fundamentals

Event listeners respond to specific events in Android apps.
Events are stored in the Android framework using a MessageQueue.
A callback method is executed in response to a specific event.
View class contains event listener interfaces.
Views must register event listeners to receive event notifications.

Layout and Adapter

ConstraintLayout is a highly efficient layout system in Android.
The Layout Editor in Android Studio is designed for ConstraintLayout.
Dynamic layouts can be populated with views at runtime using LayoutInflater.
An Adapter manages the interaction between the layout and the underlying data source.

Input Controls

Input controls, like buttons and text fields, allow user interaction.
They are typically added to a layout using android:layout_ attributes in the XML file.

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Description

Test your knowledge about common user interface controls in Android development such as Buttons, Text Fields, Checkboxes, and Radio Buttons. Learn about their functionalities and usage in mobile app development.