How to change the opacity of an image.

Question

I have an background image set to an ImageView, Now i want to change the opacity of an image without, for that i write this code to change the opacity of ImageView, but when i do so it remove the background image from the image view, So my question is how can i change the opacity of ImageView without removing background image form it.

Code i used is:

ImageView imageView = (ImageView) findViewById(R.id.image_view);

imageView.setBackgroundResource(R.drawable.theme1_page_header); // Set background image

int opacity = 100; // from 0 to 255
imageView.setBackgroundColor(opacity * 0x1000000); // change opacity of image

score 33 · Answer 1 · edited Feb 17 '14 at 23:57

the most important part of alpha is that the value has to be decimal

0 = transparent and 1 = visible

so 0.5 is half way visible

in the XML you can do

<ImageView
        android:layout_width="30dp"
        android:layout_height="35dp"
        android:id="@+id/imageView"
        android:alpha="0.4" // <-----------------  this is the fun part
        android:layout_alignParentRight="false"
        android:background="@drawable/imagename"
        android:layout_alignParentLeft="false"
        android:layout_alignParentTop="false"
        android:layout_alignWithParentIfMissing="false"
        android:layout_marginLeft="100dp"
        android:layout_alignParentBottom="false"
        android:layout_alignParentStart="false"
        android:layout_alignTop="@+id/bar"
        android:layout_marginTop="30dp"/>

score 11 · Answer 2 · answered Dec 11 '12 at 11:28

11

You can use

imageView.setAlpha(yourValue); //  some value 0-255 where 0 is fully transparent and 255 is fully opaque

See the documentation

answered Dec 11 '12 at 11:28

Renjith

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1

thanks for the answer but value is not 0-255, it should be in the range between 0-1 as float – smoothumut Apr 01 '19 at 14:37

score 5 · Answer 3 · answered Dec 11 '12 at 11:28

5

ImageView imageView = (ImageView) findViewById(R.id.image_view);
Drawable dPage_header= getResources().getDrawable(R.drawable.theme1_page_header);

// setting the opacity (alpha)
dPage_header.setAlpha(10);

// setting the images on the ImageViews
imageView.setImageDrawable(dPage_header);

answered Dec 11 '12 at 11:28

Talha

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But it is not about your first question. You can do this by checking your work percentage. you can create an method which return complatedWorkPercentage() and gives this valu to dPage_header.setAlpha(complatedWorkPercentage()); – Talha Dec 11 '12 at 11:51
i dont know what is the work ? Could you send me detail email to talhakosen@gmail.com – Talha Dec 11 '12 at 11:55
Hi talhakosen...i have send a reply to ur mail..can u please check it out – Rahul Dec 12 '12 at 07:49

score 2 · Answer 4 · edited May 23 '17 at 12:34

2

For Api >=16 . Use setImageAlpha as your practice because setAlpha will be deprecated in coming future. `

ImageView.setAlpha(int) has been renamed to ImageView.setImageAlpha(int) to avoid confusion. See Detail Explanation here

edited May 23 '17 at 12:34

Community

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1

answered Dec 22 '16 at 05:52

Zar E Ahmer

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score 1 · Answer 5 · answered Sep 16 '16 at 14:20

1

Use this option in layout xml for opacity as well as to turn the Android Material icons from Black to Grey. android:alpha=0.5

answered Sep 16 '16 at 14:20

Sachiin Gupta

378
2
9

score 1 · Answer 6 · answered Jun 29 '19 at 09:58

1

In Kotlin we can change alpha in code like this:

myImageView.alpha = 0.5f

Change alpha value to whatever you want between 0.0f to 1f

answered Jun 29 '19 at 09:58

ShadeToD

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score 0 · Answer 7 · answered Dec 11 '12 at 11:29

Option 1

Use imageView.setAlpha(100).

If you're using Android 2.3 you have to do a horrible hack with a zero-length animation using nineolddroids.

Option 2

Subclass ImageView and override its onDraw() method to draw the image transparently.

Option 3

Actually modify the image pixels using get/setPixel(). This'll be very slow though; there's probably a faster way to do this (e.g. using renderscript).

How to change the opacity of an image.

7 Answers7

Option 1

Option 2

Option 3