Set transparent background of an imageview on Android

Question

I am using a web view in which I am adding an image view. How can I set the background of this image view to transparent?

I have tried this:

mImageview.setBackgroundResource(R.color.trans);

Where trans → <color name="trans">#00000000 </color>.

Saintjust

This can help you : #5445585 – Fraase

I set #00000000 and it is transparent totally. Maybe there is some other error in your code? – Knish

Answer 1

In your XML set the Background attribute to any colour, White(#FFFFFF) shade or Black(#000000) shade. If you want transparency, just put 80 before the actual hash code:

#80000000

This will change any colour you want to a transparent one.. :)

Vyky

@Harshad: Is it possible to set, say, a 40% transparency for a background image set with View.setBackgroundResource(R.drawable.something)? – Heloise

@LuisA.Florit I found this link where you need to multiply by 0.4(40/100) to your RGB value. Not sure if this is helpful but you can give it a try. forums.esri.com/Thread.asp?c=93&f=1730&t=223940 – Vyky

@Harshad: Sorry, I didn't understand your answer. I don't have any RGB value, but a TextView with a background image that I want to be, say, 50% transparent. But, anyway, I found the answer here in stackoverflow: View.getBackground().setAlpha(50). Couldn't be simpler, right? :o) Anyway, thanks for your help!! – Heloise

If you add any number from 01 to 99 before the actual hash code, it will give you the transparency. Eg: Black with more transparency - #10000000 Black with less transparency - #99000000 – Relay

@AnhSirkDasarp Not only from 01 to 99, as the rest of the numbers these are also hexadecimal so you can put anything from 00 to ff. For fifty percent transparent you should put 80 instead of 50, and for the others you have some basic calculations to do... – Uncinariasis

I had #4e4747 as the RGB value which used to give me solid brown color. Changing it to #804e4747 is giving me black color with little transparency. why ? – Thigpen

try Color.TRANSPARENT – Legofmutton

Thanks! I was trying to apply a gradient to an imageview so I had to set 80 to both the gradient and the background of the imageview. – Cedilla

It is worth noting that this doesn't make it fully transparent. Use #00000000 instead if that's what you're going for. – Viscoid

@MarcoSalerno May be it is working but it doesn't have anything behind it. Try to overlap the views to see if it is working. – Vyky

this should help, what u should choose between "FF" and "00". tutorialspoint.com/… – Mikesell

Answer 2

You can set the background transparent of any layout, any view, or any component by adding this code in XML:

android:background="@android:color/transparent" 

Martingale

I had an issue on older versions of Android that didn't handle #ff000000 as pure transparent. Using this fixed it. – Inpour

Probably because #FF 00 00 00 = 100% black. – Stodgy

@Ioeschg The first 2 letters are for the alpha channel. #00xxxxxx would be transparent, whereas x is any hex value you want. – Angiology

And the equivalent programatically if somebody is interested is Android.Resource.Color.Transparent :) – Heterography

This shows as pure black on my app if i run it on the emulator using API 16 or 4.1.1. Any other workaround? – Kibbutznik

@undroid try android:background="#00ffffff" – Impetrate

try Color.TRANSPARENT – Legofmutton

I get No resource found that matches the given name (at 'android:statusBarColor' with value '@color/transparent'). when I try this – Divot

Answer 3

In addition to what Harshad mentioned:

Two hexadecimal characters can be appended to any hexadecimal color code. The first two characters in an 8-digit hex color code represents its opacity in Android.

The two hexadecimal characters can range from 00 to FF. For example,

• Normal opaque black hex- "#000000"
• Fully transparent - "#00000000"
• Fully opaque - "#FF000000"
• 50% transparent - "#7F000000"

This way you can change any color to any level of transparency.

To find the hexadecimal prefix from a percentage:

Divide the percentage number by 100 and multiply by 255 to get the decimal value. Convert the decimal to hexadecimal here.

For example, for 50%, 50/100 * 255 = 127. Using the link we get hexadecimal value 7F.

Source: Android: how to create a transparent or opaque background

Marmalade

actually, perfect 50% transparency is 7F and not 80 ;) – Souther

Answer 4

If you want to add 20% or 30% transparency, you should pre-pend two more characters to the hexadecimal code, like CC.

Note

android:background="#CCFF0088" in XML

where CC is the alpha value, FF is the red factor, 00 is the green factor, and 88 is the blue factor.

Some opacity code:

Hex Opacity Values

100% — FF
95% — F2
90% — E6
85% — D9
80% — CC
75% — BF
70% — B3
65% — A6
60% — 99
55% — 8C
50% — 80
45% — 73
40% — 66
35% — 59
30% — 4D
25% — 40
20% — 33
15% — 26
10% — 1A
5%  — 0D
0% —  00

You can also set opacity programmatically like:

yourView.getBackground().setAlpha(127);

Set opacity between 0 (fully transparent) to 255 (completely opaque). The 127.5 is exactly 50%.

You can create any level of transparency using the given formula. If you want half transparent:

 16 |128          Where 128 is the half of 256.
    |8 -0         So it means 80 is half transparent.

And for 25% transparency:

16 |64            Where 64 is the quarter of 256.
   |4 -0          So it means 40 is quarter transparent.

Diggins

This answer should be mark is the best. Thanks bro <3 – Kip

Answer 5

Use the below code for black:

<color name="black">#000000</color>

Now if you want to use opacity then you can use the below code:

<color name="black">#99000000</color>

And the below for opacity code:

100% — FF
95% — F2
90% — E6
85% — D9
80% — CC
75% — BF
70% — B3
65% — A6
60% — 99
55% — 8C
50% — 80
45% — 73
40% — 66
35% — 59
30% — 4D
25% — 40
20% — 33
15% — 26
10% — 1A
5% — 0D
0% — 00

Profile

Answer 6

There is already a predefined constant. Use Color.TRANSPARENT.

Journal

Use of a constant should be the best/cleanest way to go about it! But in this case, the value of Color.TRANSPARENT is set to 0x00000000 (not the expected fully opaque 0xFF000000), so depending on how you go about it, this constant might not really help accomplishing transparency! Still +1 for recommending a constant! – Fogarty

Answer 7

There is already a transparent built into Android: R.color.transparent. http://developer.android.com/reference/android/R.color.html#transparent

But I think you may want to make the background of the image that you are placing into the WebView transparent, for example, with a transparent PNG, rather than the ImageView background. If the actual image is not at all see-through then the ImageView background can't be seen through it.

Failsafe

the image is transparent..it didnt hav any background..i hv also tried setting imageview background as u hv said..but it didnt work...plz help.. – Saintjust

Can you post some more details such as a link to the image you are using and the code and layout you are using? – Failsafe

Answer 8

Try this code :)

Its an fully transparent hexa code - "#00000000"

Luciferous

Answer 9

In case you want it in code, just:

mComponentName.setBackgroundColor(Color.parseColor("#80000000"));

Advisee

Answer 10

In your XML file, set an attribute "Alpha"

such as

android:alpha="0.0" // for transparent
android:alpha="1.0" // for opaque

You can give any value between 0.0 to 1.0 in decimal to apply the required transparency. For example, 0.5 transparency is ideal for disabled component

Cobby

Answer 11

In xml

@android:color/transparent

In code

mComponentName.setBackgroundResource(android.R.color.transparent)

Olives

Answer 12

Or, as an alternate, parse the resource ID with the following code:

  mComponentName.setBackgroundColor(getResources().getColor(android.R.color.transparent));

Savell

is there an equivalent for androidX like androidx.R.color.transparent? – Convince

Answer 13

In Android Studio it is very simple to adjust color and opacity using a built-in tool:

Infamy

just click on it. @PeterMortensen – Infamy

Answer 14

For those who are still facing this problem, you may try this
element.getBackground().setAlpha(0);

Hester

I get a NullPointerException: Attempt to invoke virtual method 'void android.graphics.drawable.Drawable.setAlpha(int)' on a null object reference – Dawn

@IgorGanapolsky: try to watch your element see if it's a null object – Hester

Answer 15

Use the following for complete transparency:

#00000000

When I tried with #80000000 I got a black transparent overlay which I don't want. Try to change the first two digits; it controls the level of transparency, like

#00000000
#10000000
#20000000
#30000000

Psych

perfect color on transparent dark – Culpa

Answer 16

One more simple way:

mComponentName.setBackgroundResource(android.R.color.transparent);

Emolument

Answer 17

Another working option I came across is to set android:background="@null"

Lining

Answer 18

You could also use View.setAlpha(float) to change the visibility precisely.

0 would be transparent, 1 fully visible. ;)

Barbette

That changes the View's alpha, NOT its background! – Dawn

The whole view will then be transparent including the content/picture in it, your setting the alpha which is wrong in this case. The user want's to keep the transparency of an Image not change the Image to be transparent. – Rosalinarosalind

Answer 19

Try to use the following code. It will help you in full or more.

1. A .xml file designed to use this code to set background color:

   android:background="#000000"
   

   or

   android:background="#FFFFFF"
   

   Or you can set it programmatically as well.

2. Also you can use this code programmatically:

   image.setBackgroundDrawable(getResources().getDrawable(
       R.drawable.llabackground));
   

3. Also this code for setting the background color as well programmatically:

   image.setBackgroundColor(Color.parseColor("#FFFFFF"));
   

4. This code for the same programmatically:

   image.setBackgroundColor(getResources().getColor(Color.WHITE));
   

The color depends on your choice of which color you want to use for transparent. Mostly use a white or #FFFFFF color.

Regarding R.drawable.llabackground: This line of code is for your style of the background, like something special or different for your purpose. You can also use this.

Archimedes

Answer 20

If you use a drawable XML image you can make it transparent as shown in the picture below, or you can use a color code:

<color name="black">#99000000</color> 

Valencia

Answer 21

Color definitions with transparency information may be in the form

#AARRGGBB or #ARGB.

You can use also the shorter value for full transparency: #0000.

Other values are e.g.:

white  grey   black
#FFFF  #F888  #F000 - full color
#EFFF  #E888  #E000
#DFFF  #D888  #D000
#CFFF  #C888  #C000
#BFFF  #B888  #B000
#AFFF  #A888  #A000
#9FFF  #9888  #9000
#8FFF  #8888  #8000
#7FFF  #7888  #7000
#6FFF  #6888  #6000
#5FFF  #5888  #5000
#4FFF  #4888  #4000
#3FFF  #3888  #3000
#2FFF  #2888  #2000
#1FFF  #1888  #1000
#0FFF  #0888  #0000 - full transparency

Freemason

Answer 22

Try this:

#aa000000

For transparency 000000 = black, you can change these six numbers for the color you want.

Besnard

what is your resource to use aa before color hex – Infraction

Answer 23

ImageView.setBackground(R.drawable.my_background);

ImageView.setBackgroundResource(R.color.colorPrimary);

ImageView.getImageAlpha();

ImageView.setAlpha(125); // transparency

Rusk

Although this code may help to solve the problem, it doesn't explain why and/or how it answers the question. Providing this additional context would significantly improve its long-term value. Please edit your answer to add explanation, including what limitations and assumptions apply. – Lavoie

Answer 24

use RelativeLayout which has 2 imageViews in . and set transparency code on the top imageView.

transparency code :

<solid android:color="@color/white"/>
<gradient android:startColor="#40000000"   android:endColor="#FFFFFFFF" android:angle="270"/>

Occupy

Answer 25

Convert Percentage to hex using any online tool & than simply add it on front of color value

Example: using https://www.joshuamiron.com/percent-to-hex-converter

80% opacity would be

 <color name="opaque_80_percent">#CC000000</color>

Tamatave