I have an Android project where I'm changing the color of the Ripple effect that happens in one of my views using the following approach
Although it's working, I do need to reset this color back to it's default value, based on my style. Bellow I'll show my Style file, and I'd love to have a way to set the RippleDrawable back to it's default color.
<style name="AppTheme" parent="Theme.MaterialComponents.Light.DarkActionBar">
<item name="colorPrimary">@color/colorPrimary</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
<item name="editTextColor">@android:color/white</item>
<item name="font">@font/roboto_regular</item>
<item name="colorControlNormal">@android:color/white</item>
<item name="android:scrollbarThumbVertical">@drawable/nice_scrollbar</item>
<item name="android:textColor">@color/darkGrey</item>
<item name="android:editTextColor">@android:color/black</item>
<item name="android:textColorHighlight">@color/colorPrimary</item>
<item name="android:colorBackground">@color/darkerWhite</item>
<item name="android:windowBackground">@color/darkerWhite</item>
<item name="windowNoTitle">true</item>
<item name="android:windowNoTitle">true</item>
</style>
As it can be noticed, I'm using MaterialComponents.
Below you'll find the current method I'm using to change color and also force the ripple effect on the view at a given x/y:
private void forceRippleAnimation(View view, int x, int y) {
Drawable background = view.getBackground();
if (Build.VERSION.SDK_INT >= 21 && background instanceof RippleDrawable) {
RippleDrawable rippleDrawable = (RippleDrawable) background;
rippleDrawable.setHotspot(x, y);
rippleDrawable.setColor(new ColorStateList(
new int[][]{
new int[]{}
},
new int[]{
getContext().getResources().getColor(R.color.rippleColor)
}
));
rippleDrawable.setState(new int[]{android.R.attr.state_pressed, android.R.attr.state_enabled});
Handler handler = new Handler();
handler.postDelayed(new Runnable(){
@Override public void run(){
rippleDrawable.setState(view.getDrawableState());
}
}, 650);
}
}
Instead of trying to reverse the changes made to the original background RippleDrawable
,
you can keep it and apply the changes to a copy:
Let the Activity
have two Drawable
fields:
private RippleDrawable customRippleDrawable;
private RippleDrawable backgroundFromXml;
Create a copy of the given background and set it as the new background:
Drawable background = view.getBackground();
if (Build.VERSION.SDK_INT >= 21 && background instanceof RippleDrawable) {
backgroundFromXml = (RippleDrawable) background;
customRippleDrawable = (RippleDrawable) background.getConstantState().newDrawable().mutate();
customRippleDrawable.setHotspot(x, y);
customRippleDrawable.setColor(new ColorStateList(
new int[][]{
new int[]{}
},
new int[]{
MainActivity.this.getResources().getColor(R.color.rippleColor)
}
));
customRippleDrawable.setState(new int[]{android.R.attr.state_pressed, android.R.attr.state_enabled});
view.setBackground(customRippleDrawable);
}
Since backgroundFromXml is a field, you can access it later on to reset the background to its original value:
view.setBackground(backgroundFromXml);
What does mutate()
do?
All Drawable
s generated from one drawable resource share a common state. This helps saving resources (e.g. memory) and so will improve the performance of an android application.
Normally, if you apply for example a ColorFilter
to a Drawable
generated from a certain drawable resource, you will notice the effect everywhere in your app where this specific drawable resource is used.
Calling mutate()
on a Drawable
tells the runtime that this Drawable
should have its own state. If you apply any changes afterwards, the other Drawables wil remain unchanged.
See also the documentation on mutate()