How to set background color of a View

Question

I'm trying to set the background color of a View (in this case a Button).

I use this code:

// set the background to green
v.setBackgroundColor(0x0000FF00 );
v.invalidate();

It causes the Button to disappear from the screen. What am I doing wrong, and what is the correct way to change the background color on any View?

Thanks.

Solution 1

You made your button transparent. The first byte is the alpha.

Try v.setBackgroundColor(0xFF00FF00);

Solution 2

When you call setBackgoundColor it overwrites/removes any existing background resource, including any borders, corners, padding, etc. What you want to do is change the color of the existing background resource...

View v;
v.getBackground().setColorFilter(Color.parseColor("#00ff00"), PorterDuff.Mode.DARKEN);

Experiment with PorterDuff.Mode.* for different effects.

Solution 3

Several choices to do this...

Set background to green:

v.setBackgroundColor(0x00FF00);

Set background to green with Alpha:

v.setBackgroundColor(0xFF00FF00);

Set background to green with Color.GREEN constant:

v.setBackgroundColor(Color.GREEN);

Set background to green defining in Colors.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>     
    <color name="myGreen">#00FF00</color> 
    <color name="myGreenWithAlpha">#FF00FF00</color> 
</resources>

and using:

v.setBackgroundResource(R.color.myGreen);

and:

v.setBackgroundResource(R.color.myGreenWithAlpha);

or the longer winded:

v.setBackgroundColor(ContextCompat.getColor(getContext(), R.color.myGreen));

and:

v.setBackgroundColor(ContextCompat.getColor(getContext(), R.color.myGreenWithAlpha));

Solution 4

You can set the hex-color to any resource with:

View.setBackgroundColor(Color.parseColor("#e7eecc"));

Solution 5

// set the background to green
v.setBackgroundColor(0x0000FF00 );
v.invalidate();

The code does not set the button to green. Instead, it makes the button totally invisible.

Explanation: the hex value of the color is wrong. With an Alpha value of zero, the color will be invisible.

The correct hex value is 0xFF00FF00 for full opacity green. Any Alpha value between 00 and FF would cause transparency.

View more solutions

Comments

[RickNotFred]

That looks correct. In fact, I don't think you need to call invalidate(). When you say the button disappears, do you mean that literally or do you mean the button had text or an image on it that disappears?

[Peter vdL]

OK, thanks for the explanation about Button backgrounds. Nine patch bitmaps (developer.android.com/reference/android/graphics/NinePatch.‌​html) were new to me. I simply want to change the color of anything on the screen when I press a Button. The Buttons are on a TextView. Trying to change the color of that, leads to console messages "DDM dispatch reg wait timeout... ActivityManager: Can't dispatch DDM chunk 52454151: no handler defined" and a dialog on screen "the app stopped unexpectedly". Guess I need to do more reading on the UI. Any hints welcome. Thanks.

[Molten Ice]

EddieB's answer below is much better as this removes any borders etc. such as an EditText's underlining

[Admin]

@aroth is better Color.Green ? If I want color complext with argb ? ... your answer is deprecated

[aroth]

@delive - Come again? Color.GREEN is not deprecated, and includes the alpha byte. It's value is 0xff00ff00, exactly the same as what's suggested in the answer, except it also has the benefit of being human-readable. Most developers would prefer a human-readable solution.

[Yousha Aleayoub]

"overwrites/removes any existing background resource," not really.

[Junior Mayhé]

getResources().getColor(...) got deprecated stackoverflow.com/questions/31842983/…

[grim]

There's also: v.setBackgroundResource(R.color.myGreen); when using colors.xml

[Hashim Akhtar]

I had to use the above along with v.invalidate(); on the next line.

[Krystian]

Usually there are not a lot of default colors. New colors can be defined in res/values/colors as described here developer.android.com/samples/BasicMediaRouter/res/values/…

[weston]

Removed the invalidate calls, as you can see setBackground... methods already call that.

[weston]

v.setBackgroundColor(0x00FF00); is just their code which they say isn't working. I would also expect it to be transparent.

[Siddarth G]

tried this wasted time and went with the accepted answer, v.getBackground() gave nullpointer exception and crashed.

[Guilherme Carvalho]

This plus PorterDuff.Mode.SRC_IN solved for me so I wouldn't lose my background border.

[Peter vdL]

The question makes clear that the color change needs to be dynamic.

[Steven]

What do you write between the brackets when you want to refer to a color in your colors.xml?