How to grey out a button?

Question

You could Also make it appear as disabled by setting the alpha (making it semi-transparent). This is especially useful if your button background is an image, and you don't want to create states for it.

button.setAlpha(.5f);
button.setClickable(false);

update: I wrote the above solution pre Kotlin and when I was a rookie. It's more of a "quick'n'dirty" solution, but I don't recommend it in a professional environment.

Today, if I wanted a generic solution that works on any button/view without having to create a state list, I would create a Kotlin extension.

fun View.disable() {
    getBackground().setColorFilter(Color.GRAY, PorterDuff.Mode.MULTIPLY)
    setClickable(false)
}

In Java you can do something is similar with a static util function and you would just have to pass in the view as variable. It's not as clean but it works.

You have to provide 3 or 4 states in your btn_defaut.xml as a selector.

1. Pressed state
2. Default state
3. Focus state
4. Enabled state (Disable state with false indication; see comments)

You will provide effect and background for the states accordingly.

Here is a detailed discussion: Standard Android Button with a different color

The most easy solution is to set color filter to the background image of a button as I saw here

You can do as follow:

if ('need to set button disable')
    button.getBackground().setColorFilter(Color.GRAY, PorterDuff.Mode.MULTIPLY);
else
    button.getBackground().setColorFilter(null);

Hope I helped someone...

All given answers work fine, but I remember learning that using setAlpha can be a bad idea performance wise (more info here). So creating a StateListDrawable is a better idea to manage disabled state of buttons. Here's how:

Create a XML btn_blue.xml in res/drawable folder:

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- Disable background -->
    <item android:state_enabled="false"
          android:color="@color/md_blue_200"/>
    
    <!-- Enabled background -->
    <item android:color="@color/md_blue_500"/>
</selector>

Create a button style in res/values/styles.xml

<style name="BlueButton" parent="ThemeOverlay.AppCompat">
      <item name="colorButtonNormal">@drawable/btn_blue</item>
      <item name="android:textColor">@color/md_white_1000</item>
</style>

Then apply this style to your button:

<Button
     android:id="@+id/my_disabled_button"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:theme="@style/BlueButton"/>

Now when you call btnBlue.setEnabled(true) OR btnBlue.setEnabled(false) the state colors will automatically switch.

You should create a XML file for the disabled button (drawable/btn_disable.xml)

<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="@color/grey" />
    <corners android:radius="6dp" />
</shape>

And create a selector for the button (drawable/btn_selector.xml)

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

    <item android:drawable="@drawable/btn_disable" android:state_enabled="false"/>
    <item android:drawable="@drawable/btn_default" android:state_enabled="true"/>
    <item android:drawable="@drawable/btn_default" android:state_pressed="false" />

</selector>

Add the selector to your button

<style name="srp_button" parent="@android:style/Widget.Button">
    <item name="android:background">@drawable/btn_selector</item>
</style>