EditText Anatomy

EditText Anatomy

public class EditText extends TextView 

public class TextView extends View & implements ViewTreeObserver.OnPreDrawListener  

public class View extends Object & implements Drawable.Callback, KeyEvent.Callback, AccessibilityEventSource 

Classes Involved:

Object

Class Object is the root of the class hierarchy. Every class has Object as a superclass. All objects, including arrays, implement the methods of Object class.

View

Class View represents the basic building block for user interface controls (components). A View occupies a rectangular area on the screen and is responsible for drawing and event handling. View is the base class for widgets, which are used to create interactive UI controls; e.g., buttons, text fields, etc.

TextView

Class TextView displays text to users and optionally allows them to edit it. A TextView is a complete text editor, however, by default it is configured not to allow editing; that is why its sub-class EditText is created to configure the TextView for editing.

Interfaces Involved:

Drawable.Callback

KeyEvent.Callback

AccessibilityEventSource 

ViewTreeObserver.OnPreDrawListener

Visual Components (Controls) of EditText

Visual Components (Controls) of EditText

EditText behaves differently based on the value of its inputType property. Example:

<EditText

 android:layout_width="wrap_content"

 android:layout_height="wrap_content"

 android:inputType="textEmailAddress"

 android:ems="10"

 android:id="@+id/editText"

 android:layout_centerVertical="true"

 android:layout_centerHorizontal="true" />

Note 1: Property inputType is provided for EditText from public interface InputType as in android.text.InputType.

Note 2: All EditText controls are subclasses of TextView:

All EditText controls are subclasses of TextView

How to Create EditText with Rounded Corners?

Step 1: Create an object (a resource) from class Drawable to specify how EditText must be drawn:

<?xml version="1.0" encoding="utf-8"?>

<!-- res/drawable/edittext_rounded.xml -->

<shape xmlns:android="http://schemas.android.com/apk/res/android"

android:shape="rectangle" android:padding="10dp">

 <solid android:color="#ffffff"/>

 <corners

 android:bottomRightRadius="20dp"

 android:bottomLeftRadius="20dp"

 android:topLeftRadius="20dp"

 android:topRightRadius="20dp"/>

</shape>

Step 2: Refer to the above resource in the layout:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout

xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent" >

<EditText 

 android:layout_width="fill_parent"

 android:layout_height="wrap_content"

 android:padding="10dip"

 android:background="@drawable/edittext_rounded" />

</LinearLayout>

[continued …]

---

Copyright ©2017, Software Developer, All rights reserved.
See Contents