A lovely android view touch area extender builder class. Made to provide a larger touch area to views that aren't standard clickable android view widgets. Works well on things like a small bit of text or a little drop down arrow. The code here is from a project that uses retrolamda and google's guava library for preconditions and optionals.

Android Touch Area Extender

import android.graphics.Rect;
import android.view.TouchDelegate;
import android.view.View;

import com.google.common.base.Optional;
import com.google.common.base.Preconditions;

/**
 * Utility used to extend the touchable area around a view in a viewgroup
 * Usage: TouchAreaExtender.Builder.with(mReJamCaptionInput)
 *          .parentView(view.findViewById(R.id.rejam_dialog_root_view)).top(100).bottom(100).build();
 */
public class TouchAreaExtender {

    private TouchAreaExtender(final Builder builder) {

        final View viewToExtend = builder.mViewToExtend;
        final View parentView = builder.mParentView;
        Preconditions.checkNotNull(parentView, "Cannot do this without a parent view.");

        parentView.post(() -> {

            // Setup hit rect
            final Rect delegateArea = new Rect();
            final View delegate = viewToExtend;
            delegate.getHitRect(delegateArea);

            // Set the direction area pixel values
            delegateArea.top -= builder.mAll > 0 ? builder.mAll : builder.mTop;
            delegateArea.bottom += builder.mAll > 0 ? builder.mAll : builder.mBottom;
            delegateArea.left -= builder.mAll > 0 ? builder.mAll : builder.mLeft;
            delegateArea.right += builder.mAll > 0 ? builder.mAll : builder.mRight;

            // Set click listener if it exists
            if (builder.mViewClickListener.isPresent()) {
                viewToExtend.setOnClickListener(builder.mViewClickListener.get());
            }

            // Create touch delegate
            final TouchDelegate expandedArea = new TouchDelegate(delegateArea, delegate);

            // Give the delegate to an ancestor of the view we're delegating the area to
            if (View.class.isInstance(delegate.getParent())) {
                ((View) delegate.getParent()).setTouchDelegate(expandedArea);
            }
        });
    }

    public static class Builder {
        private View mViewToExtend;
        private View mParentView;
        private int mTop; // default is 0
        private int mBottom; // default is 0
        private int mLeft; // default is 0
        private int mRight; // default is 0
        private int mAll; // default is 0
        private Optional<View.OnClickListener> mViewClickListener = Optional.absent();

        private Builder(final View pViewToExtend) {
            this.mViewToExtend = pViewToExtend;
        }

        /**
         * Initialise with the view to want to extend the touch area of
         *
         * @param pViewToExtend
         * @return
         */
        public static Builder with(final View pViewToExtend) {
            Preconditions.checkNotNull(pViewToExtend, "Must pass in a view to extend the touch area of!");
            return new Builder(pViewToExtend);
        }

        public Builder parentView(final View mParentView) {
            Preconditions.checkNotNull(mParentView, "Must pass in a parentview!");
            this.mParentView = mParentView;
            return this;
        }

        public Builder top(final int pPx) {
            this.mTop = pPx;
            return this;
        }

        public Builder bottom(final int pPx) {
            this.mBottom = pPx;
            return this;
        }

        public Builder left(final int pPx) {
            this.mLeft = pPx;
            return this;
        }

        public Builder right(final int pPx) {
            this.mRight = pPx;
            return this;
        }

        public Builder all(final int pPx) {
            this.mAll = pPx;
            return this;
        }

        /**
         * If the view you want extend has a click listener, you will need to now pass it in here.
         * If you don't the click listener may not work.
         * @param pViewClickListener
         * @return
         */
        public Builder clickListener(final View.OnClickListener pViewClickListener) {
            Preconditions.checkNotNull(mParentView, "Cannot pass in a null clicklistener!");
            this.mViewClickListener = Optional.fromNullable(pViewClickListener);
            return this;
        }

        /**
         * Must call this to create a TouchAreaExtender with set values.
         *
         * @return
         */
        public TouchAreaExtender build() {
            return new TouchAreaExtender(this);
        }

    }
}