Bold ClickableSpan on touch

Question

I have a TextView in which every word is a ClickableSpan (actually a custom subclass of ClickableSpan). When a word is touched, it should be shown in bold font style. If I set textIsSelectable(false) on the TextView, it works just fine. The word is immediately bolded. But if text is selectable, then it does not work. BUT - if I touch a word and then turn the screen off and back on, when the screen display comes back on the word is bolded. I have tried everything I can think of to force a redraw (invalidate the TextView, force call Activity's onRestart(), refreshDrawableState() on the TextView, etc). What am I missing?

Here is my subclass of ClickableSpan:

public class WordSpan extends ClickableSpan
{
    int id;
    private boolean marking = false;
    TextPaint tp;
    Typeface font;
    int color = Color.BLACK;

    public WordSpan(int id, Typeface font, boolean marked) {
        this.id = id;
        marking = marked;
        this.font = font;
    }

    @Override
    public void updateDrawState(TextPaint ds) {
        ds.setColor(color);
        ds.setUnderlineText(false);

        if (marking)
            ds.setTypeface(Typeface.create(font,Typeface.BOLD));

        tp = ds;
    }

    @Override
    public void onClick(View v) {
        // Empty here -- overriden in activity
    }

    public void setMarking(boolean m) {
        marking = m;
        updateDrawState(tp);
    }

    public void setColor(int col) {
        color = col;
    }
}

Here is the WordSpan instantiation code in my Activity:

... looping through words

curSpan = new WordSpan(index,myFont,index==selectedWordId) {
    @Override
    public void onClick(View view) {
        handleWordClick(index,this);
        setMarking(true);
        tvText.invalidate();
    }
};

... continue loop code

And here is my custom MovementMethod:

public static MovementMethod createMovementMethod ( Context context ) {
    final GestureDetector detector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
        @Override
        public boolean onSingleTapUp ( MotionEvent e ) {
            return true;
        }

        @Override
        public boolean onSingleTapConfirmed ( MotionEvent e ) {
            return false;
        }

        @Override
        public boolean onDown ( MotionEvent e ) {
            return false;
        }

        @Override
        public boolean onDoubleTap ( MotionEvent e ) {
            return false;
        }

        @Override
        public void onShowPress ( MotionEvent e ) {
            return;
        }
    });

    return new ScrollingMovementMethod() {

        @Override
        public boolean canSelectArbitrarily () {
            return true;
        }

        @Override
        public void initialize(TextView widget, Spannable text) {
            Selection.setSelection(text, text.length());
        }

        @Override
        public void onTakeFocus(TextView view, Spannable text, int dir) {

            if ((dir & (View.FOCUS_FORWARD | View.FOCUS_DOWN)) != 0) {
                if (view.getLayout() == null) {
                    // This shouldn't be null, but do something sensible if it is.
                    Selection.setSelection(text, text.length());
                }
            } else {
                Selection.setSelection(text, text.length());
            }
        }

        @Override
        public boolean onTouchEvent ( TextView widget, Spannable buffer, MotionEvent event ) {
            // check if event is a single tab
            boolean isClickEvent = detector.onTouchEvent(event);

            // detect span that was clicked
            if (isClickEvent) {
                int x = (int) event.getX();
                int y = (int) event.getY();

                x -= widget.getTotalPaddingLeft();
                y -= widget.getTotalPaddingTop();

                x += widget.getScrollX();
                y += widget.getScrollY();

                Layout layout = widget.getLayout();
                int line = layout.getLineForVertical(y);
                int off = layout.getOffsetForHorizontal(line, x);

                WordSpan[] link = buffer.getSpans(off, off, WordSpan.class);

                if (link.length != 0) {
                    // execute click only for first clickable span
                    // can be a for each loop to execute every one

                    if (event.getAction() == MotionEvent.ACTION_UP) {
                        link[0].onClick(widget);
                        return true;
                    }
                    else if (event.getAction() == MotionEvent.ACTION_DOWN) {
                        Selection.setSelection(buffer,
                                               buffer.getSpanStart(link[0]),
                                               buffer.getSpanEnd(link[0]));

                        return false;
                    }
                }
                else {

                }
            }

            // let scroll movement handle the touch
            return super.onTouchEvent(widget, buffer, event);
        }
    };
}

Answer 1

Your spans are somehow becoming immutable when the text is set as selectable (TextView#setTextIsSelectable(true)). Here is a good write-up on Understanding Spans that explains mutability of spans. I also think that this post has some good explanations

I am not sure how your spans are getting to be immutable. Maybe they are mutable but just not showing somehow? It is unclear. Maybe someone has an explanation for this behavior. But, for now, here is a fix:

When you rotate your device or turn it off and back on, the spans are recreated or just reapplied. That is why you see the change. The fix is to not try to change the spans when clicked, but to reapply it with the font bolded. That way the change will take effect. You will not even need to call invalidate(). Keep track of the bolded span so it can be unbolded later when another span is clicked.

Here is the result:

Here is main activity. (Please forgive all the hard-coding, but this is just a sample.)

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private TextView mTextView;
    private WordSpan mBoldedSpan;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Typeface myFont = Typeface.DEFAULT;

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTextView = findViewById(R.id.textView);
        mTextView.setTextIsSelectable(true);

        mTextView.setMovementMethod(createMovementMethod(this));
        SpannableString ss = new SpannableString("Hello world! ");
        int[][] spanStartEnd = new int[][]{{0, 5}, {6, 12}};
        for (int i = 0; i < spanStartEnd.length; i++) {
            WordSpan wordSpan = new WordSpan(i, myFont, false) {
                @Override
                public void onClick(View view) {
//                handleWordClick(index, this); // Not sure what this does.
                    Spannable ss = (Spannable) mTextView.getText();
                    if (mBoldedSpan != null) {
                        reapplySpan(ss, mBoldedSpan, false);
                    }
                    reapplySpan(ss, this, true);
                    mBoldedSpan = this;
                }

                private void reapplySpan(Spannable spannable, WordSpan span, boolean isBold) {
                    int spanStart = spannable.getSpanStart(span);
                    int spanEnd = spannable.getSpanEnd(span);
                    span.setMarking(isBold);
                    spannable.setSpan(span, spanStart, spanEnd, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
                }
            };
            ss.setSpan(wordSpan, spanStartEnd[i][0], spanStartEnd[i][1],
                       Spanned.SPAN_INCLUSIVE_INCLUSIVE);
        }

        mTextView.setText(ss, TextView.BufferType.SPANNABLE);
    }
    // All the other code follows without modification.
}

activity_main.xml

<android.support.constraint.ConstraintLayout 
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.04000002"
        tools:text="Hello World!" />

</android.support.constraint.ConstraintLayout>

Here is version that uses a StyleSpan. The results are the same.

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private TextView mTextView;
    private StyleSpan mBoldedSpan;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Typeface myFont = Typeface.DEFAULT;

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTextView = findViewById(R.id.textView);
        mTextView.setTextIsSelectable(true);

        mTextView.setMovementMethod(createMovementMethod(this));
        mBoldedSpan = new StyleSpan(android.graphics.Typeface.BOLD);
        SpannableString ss = new SpannableString("Hello world!");
        int[][] spanStartEnd = new int[][]{{0, 5}, {6, 12}};
        for (int i = 0; i < spanStartEnd.length; i++) {
            WordSpan wordSpan = new WordSpan(i, myFont, false) {
                @Override
                public void onClick(View view) {
//                handleWordClick(index, this); // Not sure what this does.
                    Spannable ss = (Spannable) mTextView.getText();
                    ss.setSpan(mBoldedSpan, ss.getSpanStart(this), ss.getSpanEnd(this),
                               Spanned.SPAN_INCLUSIVE_INCLUSIVE);
                }
            };
            ss.setSpan(wordSpan, spanStartEnd[i][0], spanStartEnd[i][1],
                       Spanned.SPAN_INCLUSIVE_INCLUSIVE);
        }

        mTextView.setText(ss, TextView.BufferType.SPANNABLE);
    }

 // All the other code follows without modification.
}