TextViewWithLinks.java

package com.orgzly.android.ui.views;

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.v7.widget.AppCompatTextView;
import android.text.Layout;
import android.text.Spanned;
import android.text.style.ClickableSpan;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.TextView;

import com.orgzly.BuildConfig;
import com.orgzly.android.util.LogUtils;

/**
 * {@link TextView} with links support.
 */
public class TextViewWithLinks extends AppCompatTextView {
    public static final String TAG = TextViewWithLinks.class.getName();

    public TextViewWithLinks(Context context) {
        super(context);
    }

    public TextViewWithLinks(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public TextViewWithLinks(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    public boolean onTouchEvent(@NonNull MotionEvent event) {
        if (BuildConfig.LOG_DEBUG) LogUtils.d(TAG, event);

        Layout layout = this.getLayout();

        if (layout != null) {
            int line = layout.getLineForVertical((int) event.getY() - getTotalPaddingTop());
            int offset = getOffsetForPosition(event.getX(), event.getY());

            if (isEventOnText(event, layout, line) && getText() != null && getText() instanceof Spanned) {
                Spanned spanned = (Spanned) getText();

                ClickableSpan[] links = spanned.getSpans(offset, offset, ClickableSpan.class);

                if (links.length > 0) {
                    if (event.getAction() == MotionEvent.ACTION_DOWN) {
                        return true;

                    } else if (event.getAction() == MotionEvent.ACTION_UP) {
                        links[0].onClick(this);

                    } else {
                        return super.onTouchEvent(event);
                    }
                }
            }
        }

        return super.onTouchEvent(event);
    }

    /**
     * Check if event's coordinates are within line's text.
     *
     * Needed as getOffsetForHorizontal will return closest character,
     * which is an issue when clicking the empty space next to the text.
     */
    private boolean isEventOnText(MotionEvent event, Layout layout, int line) {
        float left = layout.getLineLeft(line) + getTotalPaddingLeft();
        float right = layout.getLineRight(line) + getTotalPaddingRight();
        float bottom = layout.getLineBottom(line) + getTotalPaddingTop();
        float top = layout.getLineTop(line) + getTotalPaddingTop();

        return left <= event.getX() && event.getX() <= right &&
               top <= event.getY() && event.getY() <= bottom;
    }
}