Quick Answer: What Is FindViewById?

Why does FindViewById return null?

FindViewById can be null if you call the wrong super constructor in a custom view.

The ID tag is part of attrs, so if you ignore attrs, you delete the ID..

What is set content view in Android?

Actually setContentView() is a method part of android. app. Activity class. It helps to set our content or render our layout on the screen. Based on the value given by the user, views will be inflated and rendered after the measurement of the screen, root view, and its child views.

How do you kill an activity?

9 Answers. You can also add android:noHistory=”true” to your Activity tag in AndroidManifest. xml . Yes, all you need to do is call finish() in any Activity you would like to close.

What is difference between Wrap_Content and Match_Parent?

Define Major differences between match_parent, fill_parent, wrap_content attributes with examples. Match_Parent : Definition of match parent is to match width and height same as its parent attribute tag. … Wrap_Content : Definition of wrap content is to cover the only its included content + declared padding size.

What does findViewById return?

findViewById returns an instance of View , which is then cast to the target class. All good so far. To setup the view, findViewById constructs an AttributeSet from the parameters in the associated XML declaration which it passes to the constructor of View .

What is Android padding?

The padding is expressed in pixels for the left, top, right and bottom parts of the view. Padding can be used to offset the content of the view by a specific number of pixels. For instance, a left padding of 2 will push the view’s content by 2 pixels to the right of the left edge.

What is the use of view in Android?

View objects are used specifically for drawing content onto the screen of an Android device. While you can instantiate a View in your Java code, the easiest way to use them is through an XML layout file. An example of this can be seen when you create an simple “Hello World” application in Android Studio.

What is the purpose of TextView?

A TextView displays text to the user and optionally allows them to edit it. A TextView is a complete text editor, however the basic class is configured to not allow editing.

What does focusable mean Android?

Focusable means that it can gain the focus from an input device like a keyboard. Input devices like keyboards cannot decide which view to send its input events to based on the inputs itself, so they send them to the view that has focus.

What is FindViewById () method used for?

It does this by writing the attribute android:id=”@id+/today” in the TextView’s description in the layout file. (The R stands for “resource†.) Every Activity object has a method named findViewById, which finds a View object given its ID number.

How do you inflate a view on Android?

inflate(R. layout. custom_button, mLinearLayout, true); We specified that we want to inflate the Button from its layout resource file; we then tell the LayoutInflater that we want to attach it to mLinearLayout .

Which of the following is used to set the background color in Android?

android:background=”” is the attribute used to set background for any Layout file. You can directly specify the value as HEX color code as we do for CSS files in HTML.