Android Note: Button

A button consists of text or an icon (or both text and an icon) that communicates what action occurs when the user touches it.

Depending on whether you want a button with text, an icon, or both, you can create the button in your layout in three ways:

· With text, using the Button class:

· With text and an icon, using the Button class with the android:drawableLeft attribute:

Text

Set the text to textview

Code - android:text="your text here"

Text Size

Specify the size of the size.

Size of text like - 16dp, 20sp, 2em ( 1em= 16dp )

code  - android:textSize="16dp"

Text Alignment

Set Text Left, Right, Centre and more in EditText

code - android:textAlignment="center"

Text All Caps

Make all text Capital in Textview

must be a boolean ( true/False )

code -  android:textAllCaps="true"

Text Color

Set the color of the text.

Color should be Hexadecimal (#000000 - #ffffff), octal [Range 0-255] ( rgb(212,212,212,0.5 )

code - android:textColor="#12E9fa"

borderLessButton

To create a borderless button, apply the borderlessButtonStyle style to the button. For example:

style="?android:attr/borderlessButtonStyle"

Background

Set the background color as a image, color.

code - android:background="@drawable/abc"

Text Style

Style (bold , italic, bolditalic) for the text.

Must be one or more (separated by '|') of the following constant values.

Value -

Normal - 0

Bold - 1

Italic - 2

code - android:textStyle="bold"

Typeface

Typeface (normal, sans, serif, monospace) for the text.

Must be one of the following constant values.

Value -

Normal - 0

Sans - 1

Serif - 2

Monospace - 3

code  - android:typeface="monospace"

Text Appearance

Default appearance of text: color, typeface, size, and style.

code - android:textAppearance="@style/TextAppearance.AppCompat.Large"

Some Attribute -

textAppearanceLarge : style for "large" text. Defaults to primary text color.

Text Color Highlight

Color of the text selection highlight.

code - android:textColorHighlight="#12e7ff"

Text Direction

Set the direction of the text

rtl for Right to Left direction.

code - android:textDirection="rtl"

Text Single Line

Constrains the text to a single horizontally scrolling line instead of letting it wrap onto multiple lines,

Must be boolean ( True / False )

code - android:singleLine="true"

Text Shadow color

Place a blurred shadow of text underneath the text, drawn with the specified color.

Must be a color value, in the form of "#rgb", "#argb", "#rrggbb", or "#aarrggbb" or hex (#ffaa77)

code - android:shadowColor="#aa6600"

Text ShadowDX

Horizontal offset of the text shadow.

Must be a floating point value, such as "1.2".

code - android:shadowDx="1.2"

Text ShadowDY

Vertical offset of the text shadow.

Must be a floating point value, such as "1.2".

code - android:shadowDy="1.2"

Text Shadow Radius

Blur radius of the text shadow.

Must be a floating point value, such as "1.2".

code - android:shadowRadius="1.2"

Text IsSelectable

Indicates that the content of a non-editable text can be selected.

Must be a boolean value, either "true" or "false".

code - android:textIsSelectable="true"

Text ScaleX

Sets the horizontal scaling factor for the text.

Must be a floating point value, such as "1.2".

Code - android:textScaleX="12"

Visibility

show or hide the edittext

Must be 'Visible', 'Invisivble' or 'Gone'.

code  - android:visibility="invisible"

Letter Spacing

Specing between character .

Must be a floating point value, such as "1.2".

method - android:letterSpacing="2"  range:"1 to depend on you"

Line Spacing

Spacing between two line

code - android:lineSpacingExtra="16dp"

Hint

Show hint for type of input

Method - android:hint="search_hint"

Hint Color

Set color for hint text

code - android:textColorHint="#ff6600"

Line

Makes the TextView be exactly this many lines tall.

Must be an integer value, such as "3".

Code - android:lines="2"

Font Family

Font family (named by string) for the text.

Must be a string value, using '\\;' to escape characters such as '\\n' or '\\uxxxx' for a unicode character.

code - android:fontFamily="cursive"

Gravity

Specifies how to align the text by the view's x- and/or y-axis when the text is smaller than the view.

Attribute are - top, bottom, left, right, centre, start, end

code - android:gravity="center"

Margin

Specifies extra space on the bottom side of this view. This space is outside this view's bounds. Margin values should be positive.

Must be a dimension value, which is a floating point number appended with a unit such as "14.5sp". Available units are: px (pixels), dp (density-independent pixels), sp (scaled pixels based on preferred font size), in (inches), mm (millimeters).

Code - android:layout_margin="46dp"

XML Attributes
Attribute Name	Related Method	Description
android:layout_marginBottom	setMargins(int,int,int,int)	Specifies extra space on the bottom side of this view.
android:layout_marginEnd	setMarginEnd(int)	Specifies extra space on the end side of this view.
android:layout_marginLeft	setMargins(int,int,int,int)	Specifies extra space on the left side of this view.
android:layout_marginRight	setMargins(int,int,int,int)	Specifies extra space on the right side of this view.
android:layout_marginStart	setMarginStart(int)	Specifies extra space on the start side of this view.
android:layout_marginTop	setMargins(int,int,int,int)	Specifies extra space on the top side of this view.

Padding

Sets the padding, in pixels, of all four edges. Padding is defined as space between the edges of the view and the view's content. A views size will include it's padding. If a background is provided, the padding will initially be set to that (0 if the drawable does not have padding). Explicitly setting a padding value will override the corresponding padding found in the background.

code - android:padding="16dp"

XML Attributes
Attribute Name	Related Method	Description
android:paddingBottom	setMargins(int,int,int,int)	Sets the padding, in pixels, of the bottom edge; see padding.
android:paddingEnd	setMarginEnd(int)	Sets the padding, in pixels, of the end edge; see padding.
android: paddingLeft	setMargins(int,int,int,int)	Sets the padding, in pixels, of the left edge; see padding.
android: paddingRight	setMargins(int,int,int,int)	Sets the padding, in pixels, of the right edge; see padding.
android: paddingStart	setMarginStart(int)	Sets the padding, in pixels, of the start edge; see padding.
android: paddingTop	setMargins(int,int,int,int)	Sets the padding, in pixels, of the top edge; see padding.

onClick

Name of the method in this View's context to invoke when the view is clicked. This name must correspond to a public method that takes exactly one parameter of type View. For instance, if you specify android:onClick="sayHello", you must declare a

public void
sayHello(View v)

method of your context (typically, your Activity).

Must be a string value, using '\\;' to escape characters such as '\\n' or '\\uxxxx' for a unicode character.

code - android:onClick="method name"

rotation

rotation of the view, in degrees.

Must be a floating point value, such as "1.2".

code  - android:rotation="12"

Attribute - Description

android:rotationX - rotation of the view around the x axis, in degrees.

android:rotationY - rotation of the view around the y axis, in degrees.

Save Enabled

If false, no state will be saved for this view when it is being frozen. The default is true, allowing the view to be saved (however it also must have an ID assigned to it for its state to be saved). Setting this to false only disables the state for this view, not for its children which may still be saved.

Must be a boolean value, either "true" or "false".

code - android:saveEnabled="false"

Sound Effect Enabled

Boolean that controls whether a view should have sound effects enabled for events such as clicking and touching.

Must be a boolean value, either "true" or "false".

code - android:soundEffectsEnabled="true"

Tag

Supply a tag for this view containing a String, to be retrieved later with View.getTag() or searched for with View.findViewWithTag(). It is generally preferable to use IDs (through the android:id attribute) instead of tags because they are faster and allow for compile-time type checking.

Must be a string value, using '\\;' to escape characters such as '\\n' or '\\uxxxx' for a unicode character.

code  -  android:tag="tag name here"

ForeGround

Defines the drawable to draw over the content. This can be used as an overlay. The foreground drawable participates in the padding of the content if the gravity is set to fill.

May be a color value, in the form of "#rgb", "#argb", "#rrggbb", or "#aarrggbb" or image

code - android:foreground="@drawable/abc"

foreGround Gravity

Defines the gravity to apply to the foreground drawable. The gravity defaults to fill.

Must be one or more (separated by '|') of the following constant values.

Constant	Value	Description
top	0x30	Push object to the top of its container, not changing its size.
bottom	0x50	Push object to the bottom of its container, not changing its size.
left	0x03	Push object to the left of its container, not changing its size.
right	0x05	Push object to the right of its container, not changing its size.
center_vertical	0x10	Place object in the vertical center of its container, not changing its size.
fill_vertical	0x70	Grow the vertical size of the object if needed so it completely fills its container.
center_horizontal	0x01	Place object in the horizontal center of its container, not changing its size.
fill_horizontal	0x07	Grow the horizontal size of the object if needed so it completely fills its container.
center	0x11	Place the object in the center of its container in both the vertical and horizontal axis, not changing its size.
fill	0x77	Grow the horizontal and vertical size of the object if needed so it completely fills its container.
clip_vertical	0x80	Additional option that can be set to have the top and/or bottom edges of the child clipped to its container's bounds. The clip will be based on the vertical gravity: a top gravity will clip the bottom edge, a bottom gravity will clip the top edge, and neither will clip both edges.
clip_horizontal	0x08	Additional option that can be set to have the left and/or right edges of the child clipped to its container's bounds. The clip will be based on the horizontal gravity: a left gravity will clip the right edge, a right gravity will clip the left edge, and neither will clip both edges.

foregroundTint

Tint to apply to the foreground. if your foreground is image then overwrite with tint color.

Must be a color value, in the form of "#rgb", "#argb", "#rrggbb", or "#aarrggbb".

android:foregroundTint="#12e7ff"

foregroundTintMode

Blending mode used to apply the foreground tint. awsm

Must be one of the following constant values.

Constant	Value	Description
src_over	3	The tint is drawn on top of the drawable. [Sa + (1 - Sa)Da, Rc = Sc + (1 - Sa)Dc]
src_in	5	The tint is masked by the alpha channel of the drawable. The drawable’s color channels are thrown out. [Sa * Da, Sc * Da]
src_atop	9	The tint is drawn above the drawable, but with the drawable’s alpha channel masking the result. [Da, Sc Da + (1 - Sa) * Dc]*
multiply	14	Multiplies the color and alpha channels of the drawable with those of the tint. [Sa * Da, Sc * Dc]
screen	15	[Sa + Da - Sa * Da, Sc + Dc - Sc * Dc]
add	16	Combines the tint and drawable color and alpha channels, clamping the result to valid color values. Saturate(S + D)

code -  android:foregroundTintMode="add"

//------------------------------- Scroll bar start here

ScrollIndicators

Defines which scroll indicators should be displayed when the view can be scrolled. Multiple values may be combined using logical OR, for example "top|bottom".

Must be one or more (separated by '|') of the following constant values.

Constant	Value	Description
none	0x00	No scroll indicators are displayed.
top	0x01	Displays top scroll indicator when view can be scrolled up.
bottom	0x02	Displays bottom scroll indicator when vew can be scrolled down.
left	0x04	Displays left scroll indicator when vew can be scrolled left.
right	0x08	Displays right scroll indicator when vew can be scrolled right.
start	0x10	Displays right scroll indicator when vew can be scrolled in the start direction.
end	0x20	Displays right scroll indicator when vew can be scrolled in the end direction.

code - android:scrollIndicators="bottom"

ScrollX

The initial horizontal scroll offset, in pixels.

code - android:scrollX="14sp"

ScrollY

The initial vertical scroll offset, in pixels.

code - android:scrollY="14sp"

scrollbarAlwaysDrawHorizontalTrack

Defines whether the horizontal scrollbar track should always be drawn.

Must be a boolean value, either "true" or "false".

android:scrollbarAlwaysDrawHorizontalTrack="true"

Below code for vertical

  android:scrollbarAlwaysDrawVerticalTrack="true"

scrollbarDefaultDelayBeforeFade

Defines the delay in milliseconds that a scrollbar waits before fade out.

Must be an integer value, such as "100".

code - android:scrollbarDefaultDelayBeforeFade="100"

scrollbarFadeDuration

Defines the delay in milliseconds that a scrollbar takes to fade out.

Must be an integer value, such as "100".

code - android:scrollbarFadeDuration="100"

scrollbarSize

Sets the width of vertical scrollbars and height of horizontal scrollbars.

code  - android:scrollbarSize="100dp"

scrollbarStyle

Controls the scrollbar style and position. The scrollbars can be overlaid or inset. When inset, they add to the padding of the view. And the scrollbars can be drawn inside the padding area or on the edge of the view. For example, if a view has a background drawable and you want to draw the scrollbars inside the padding specified by the drawable, you can use insideOverlay or insideInset. If you want them to appear at the edge of the view, ignoring the padding, then you can use outsideOverlay or outsideInset.

Must be one of the following constant values.

Constant	Value	Description
insideOverlay	0x0	Inside the padding and overlaid
insideInset	0x01000000	Inside the padding and inset
outsideOverlay	0x02000000	Edge of the view and overlaid
outsideInset	0x03000000	Edge of the view and inset

scrollbarThumbHorizontal

Defines the horizontal scrollbar thumb drawable.

android:scrollbarThumbHorizontal="@drawable/abc"

scrollbarThumbVertical

Defines the vertical scrollbar thumb drawable.

android:scrollbarThumbVertical="@drawable/abc"

scrollbarTrackHorizontal

Defines the horizontal scrollbar track drawable.

code - android:scrollbarTrackHorizontal="@drawable/abc"

scrollbarTrackVertical

Defines the vertical scrollbar track drawable.

code - android:scrollbarTrackVertical="@drawable/abc"

scrollbars

Defines which scrollbars should be displayed on scrolling or not.

Must be one or more (separated by '|') of the following constant values.

Constant	Value	Description
none	0x00000000	No scrollbar is displayed.
horizontal	0x00000100	Displays horizontal scrollbar only.
vertical	0x00000200	Displays vertical scrollbar only.

code - android:scrollbars="horizontal"

--------------------------------------

Java Code

XML PART

<Button

    android:id="@+id/button1"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:hint=" button hint text"

    />

JAVA PART

public class MainActivity extends AppCompatActivity {



    Button button;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        button =( Button) findViewById(R.id. button1);  // edittext initialization

        

    }

}

getText()

Obtain text from textView and store it.

Runtime

String string = button.getText().toString();

setText()

Set text to edittext .

Runtime

button.setText(" Set this value to button ");

Directly, parse value to editText

or

String string = " Set this value to button ";

button.getText(string);

Store the value to a string first and then set to button.

selectAll

select all text of view

Place this code inside button.

code - button.selectAll();

setBackGroundColor

Change the color of button.

code - button.setBackgroundColor(Color.DKGRAY);

button.setBackgroundColor(Color.parseColor("#12e7ff"));

append

Add text or string to view or any character sequence.

Code - button.append( string );

 example - button.append("hello");

or

String hello="hello diva";

button.append(hello);

append (CharSequence text, int start, int end)

add text in view with specified range ( start and end range )

code - button.append(Char squence, int start,int end);

like - button.append("hellodivakar",3,5);

this code only 'lo' to string

borderLessStyle

One design that can be useful is a "borderless" button. Borderless buttons resemble basic buttons except that they have no borders or background but still change appearance during different states, such as when clicked.

To create a borderless button, apply the borderlessButtonStyle style to the button. For example:

<Button

    android:id="@+id/button_send"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:text="@string/button_send"

    android:onClick="sendMessage"

    style="?android:attr/borderlessButtonStyle" />

style="@style/Widget.AppCompat.Button"

style="@style/Widget.AppCompat.Button.Colored"

style="@style/Widget.AppCompat.Button.Borderless"

style="@style/Widget.AppCompat.Button.Borderless.Colored"

Custom Background

If you want to truly redefine the appearance of your button, you can specify a custom background. Instead of supplying a simple bitmap or color, however, your background should be a state list resource that changes appearance depending on the button's current state.

Create a new XML file in the res/drawable/ directory (name it something like button_custom.xml). Insert the following XML:

part-I

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/button_pressed"
android:state_pressed="true" />
<item android:drawable="@drawable/button_focused"
android:state_focused="true" />
<item android:drawable="@drawable/button_default" />
</selector>

part-II

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

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



    <item android:state_pressed="true" >

        <shape>

            <solid android:color="#FF0000" />

        </shape>

    </item>



    <item android:state_focused="true" >

        <shape>

            <solid android:color="#DDDDDD" />

        </shape>

    </item>



    <item>

        <shape>

            <solid android:color="#994fff" />

            <corners android:topLeftRadius="40dp" />

        </shape>

    </item>



</selector>

This XML file now represents a single drawable resource and when referenced by a Button for its background, the image displayed will change based on these three states.

Then simply apply the drawable XML file as the button background:

onClick Method

Onclick handlers are used to execute a part of code when a button or other part of the user interface is touched (clicked). These onClick handlers are an instance of a class that you need to specify. In short it’s an object with a piece of executable code that get’s triggered by a user interaction.

and place this code in java file -

public void method_name(View v) {

//Inform the user the button has been clicked

Toast.makeText(this, "Button1 clicked.", Toast.LENGTH_SHORT).show();

}

onClickListner

You can also declare the click event handler programmatically rather than in an XML layout. This might be necessary if you instantiate the Button at runtime or you need to declare the click behavior in a Fragmentsubclass.

To declare the event handler programmatically, create an View.OnClickListener object and assign it to the button by calling setOnClickListener(View.OnClickListener). For example:

Button button = (Button) findViewById(R.id.button_send);

button.setOnClickListener(new View.OnClickListener() {

    public void onClick(View v) {

        // Do something in response to button click

    }

});

STYLING

add style-shape

Add shape to editext.

Step 1. create a xml file (radiant_bachground.xml ) to drawable folder and place this code

radial_background.xml

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

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

<gradient

android:type="radial"

android:startColor="#343030"

android:endColor="#151515"

android:gradientRadius="300"

android:angle="270"

android:centerY="0.3"/>

</shape>

step -2. Add this code to your view ( edittext, textview, button or more ) to change background

android:background="@drawable/radial_background"

Android Note

Wednesday 17 August 2016

Button

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