在 Android 视图中以编程方式设置“ ? selectableItemBack”

在 xml 中，我经常这样做来模拟 onClick效果:

<android.support.v7.widget.CardView
android:id="@+id/cardView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:foreground="?selectableItemBackground">


...


</android.support.v7.widget.CardView>

有没有办法在 Java 中访问 ?selectableItemBackground？

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Try below code.

int[] attrs = new int[]{R.attr.selectableItemBackground};
TypedArray typedArray = context.obtainStyledAttributes(attrs);
int backgroundResource = typedArray.getResourceId(0, 0);
cardView.setBackgroundResource(backgroundResource);
cardView.setClickable(true);
typedArray.recycle();
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最佳答案

For appcompat you can use,

TypedValue outValue = new TypedValue();
getContext().getTheme().resolveAttribute(android.R.attr.selectableItemBackground, outValue, true);
cardView.setBackgroundResource(outValue.resourceId);
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You should reference it as

android.R.attr.selectableItemBackground

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I was looking for the same solution. I slightly changed this answer to make it more suitable for the asked question. Call the following code from your constructor.

private void setClickableAnimation(Context context)
{
TypedValue outValue = new TypedValue();
context.getTheme().resolveAttribute(
android.R.attr.selectableItemBackground, outValue, true);
setForeground(getDrawable(context, outValue.resourceId));
}
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For those who work with Kotlin, here are some extensions functions to add Ripple on Android View type :

private fun View.addRipple() = with(TypedValue()) {
context.theme.resolveAttribute(android.R.attr.selectableItemBackground, this, true)
setBackgroundResource(resourceId)
}


private fun View.addCircleRipple() = with(TypedValue()) {
context.theme.resolveAttribute(android.R.attr.selectableItemBackgroundBorderless, this, true)
setBackgroundResource(resourceId)
}
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From a fragment:

TypedValue outValue = new TypedValue();
requireContext().getTheme().resolveAttribute(android.R.attr.selectableItemBackground, outValue, true);
cardView.setBackgroundResource(outValue.resourceId);

From an adapter declaring in its constructor the context or the same fragment:

TypedValue outValue = new TypedValue();
fragment.requireContext().getTheme().resolveAttribute(android.R.attr.selectableItemBackground, outValue, true);
holder.cardView.setBackgroundResource(outValue.resourceId);
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Based on @Wirling answer we can use foreground to set both the color and the ripple effect

Note: Foreground requires android API level 23(M) and above:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
TypedValue outValue = new TypedValue();
getContext().getTheme().resolveAttribute(android.R.attr.selectableItemBackground, outValue, true);
view.setForeground(getDrawable(getContext(), outValue.resourceId));
}
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For Kotlin I'm using

binding.yourCoolView.apply {
background = with(TypedValue()) {
context.theme.resolveAttribute(
R.attr.selectableItemBackground, this, true)
ContextCompat.getDrawable(context, resourceId)
}
}
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For people using Kotlin, this is an extended version of @Nicolas answer. If you are using CardView, you need to change the foreground, not the background.

Code

fun View.addBackgroundRipple() = with(TypedValue()) {
context.theme.resolveAttribute(android.R.attr.selectableItemBackground, this, true)
setBackgroundResource(resourceId)
}


fun View.addBackgroundCircleRipple() = with(TypedValue()) {
context.theme.resolveAttribute(android.R.attr.selectableItemBackgroundBorderless, this, true)
setBackgroundResource(resourceId)
}


fun View.addForegroundRipple() = with(TypedValue()) {
context.theme.resolveAttribute(android.R.attr.selectableItemBackground, this, true)
foreground = ContextCompat.getDrawable(context, resourceId)
}


fun View.addForegroundCircleRipple() = with(TypedValue()) {
context.theme.resolveAttribute(android.R.attr.selectableItemBackgroundBorderless, this, true)
foreground = ContextCompat.getDrawable(context, resourceId)
}

Usage

// Background ripple
linearLayout.addBackgroundRipple()


// Foreground ripple
cardView.addForegroundRipple()

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