Adjust background to text on TextView in android

I'd like to know if anyone could help me with this.

I've got a textView and I want the background just to be applied to 开发者_如何学Gothe text, according to its size, not to the whole textView.

There is no problem when the text is only one row lenghth, but there is when it takes more than one line...

Maybe this pic helps to understand this all...

top: what I have bottom: what I want

Thank you :-)

Try using something like this:

TextView tv = (TextView) findViewById(R.id.myid);
tv.setText(Html.fromHtml("<span style="background: red;">Text</span>"));

It might resolve your issue...

EDIT:

I found the solution here : Set color of TextView span in Android using SpannableString

Use of HTML span tag doesn't work for me. Try this running code:

String str = "This is highlighted text";
TextView textview = (TextView) findViewById (R.id.textview);
SpannableStringBuilder style = new SpannableStringBuilder (str);
style.setSpan (new BackgroundColorSpan (Color.RED), 0, str.lenght(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
textview.setText(style);

This worked for me

TextView tv = (TextView) findViewById(R.id.tvMyText); tv.setText("Some Text"); tv.setBackgroundColor(Color.CYAN);

I took this solution and added the automatic gravity management. The intial solution is only for the start/left gravity. The displayed version supports Gravity.START and Gravity.END with LTR and RTL detection.

So this is my updated version in Kotlin:

     /*
 * When trying to put a background color on the text only within textview, there is no padding. This
 * class allows a padding in this circumstance. The source is linked below.
 * Was edited by Maxime, to add a gravity switcher because the default code in the source is only working for gravity start
 * Source: https://medium.com/@tokudu/android-adding-padding-to-backgroundcolorspan-179ab4fae187
 *
 */
class PaddingBackgroundColorSpan(private val mBackgroundColor: Int, private val mPadding: Int, private val gravity: Int) : LineBackgroundSpan {
    private val backgroundRect = Rect()

    override fun drawBackground(c: Canvas, p: Paint, left: Int, right: Int, top: Int, baseline: Int, bottom: Int, text: CharSequence, start: Int, end: Int, lnum: Int) {
        val textWidth = Math.round(p.measureText(text, start, end))
        val paintColor = p.color

        val finalTop = top - if (lnum == 0) mPadding / 2 else -(mPadding / 2)
        val finalBottom = bottom + mPadding / 2
        val isLeftToRight = TextUtils.getLayoutDirectionFromLocale(Locale.getDefault()) == View.LAYOUT_DIRECTION_LTR
        // Draw the background
        backgroundRect.set(when {
            gravity == Gravity.LEFT || (isLeftToRight &&  gravity == Gravity.START) || (!isLeftToRight &&  gravity == Gravity.END) -> getLeftRect(left, finalTop, right, finalBottom, textWidth)
            gravity == Gravity.CENTER -> getCenterRect(left, finalTop, right, finalBottom, textWidth)
            gravity == Gravity.RIGHT || (isLeftToRight &&  gravity == Gravity.RIGHT) || (!isLeftToRight &&  gravity == Gravity.START) -> getRightRect(left, finalTop, right, finalBottom, textWidth)
            else -> {
                getLeftRect(left, finalTop, right, finalBottom, textWidth)
            }
        })

        p.color = mBackgroundColor
        c.drawRect(backgroundRect, p)
        p.color = paintColor
    }

    /**
     * Method to process the rectangle where the background (with its padding) will be drawn when the
     * text gravity left
     * @param left - left coordinate of the textView relative to its parent
     * @param top - top coordinate of the textView relative to its parent
     * @param right - right coordinate of the textView relative to its parent
     * @param bottom - bottom coordinate of the textView relative to its parent
     * @param textWidth - the width of the textView
     *
     * @return Rect - containing the coordinates to draw the background
     */
    private fun getLeftRect(left: Int, top: Int, right: Int, bottom: Int, textWidth: Int): Rect {
        return Rect(left - mPadding, top, left + textWidth + mPadding, bottom)
    }

    /**
     * Method to process the rectangle where the background (with its padding) will be drawn when the
     * text gravity right
     * @param left - left coordinate of the textView relative to its parent
     * @param top - top coordinate of the textView relative to its parent
     * @param right - right coordinate of the textView relative to its parent
     * @param bottom - bottom coordinate of the textView relative to its parent
     * @param textWidth - the width of the textView
     *
     * @return Rect - containing the coordinates to draw the background
     */
    private fun getRightRect(left: Int, top: Int, right: Int, bottom: Int, textWidth: Int): Rect {
        return Rect(right - textWidth - mPadding, top, right + mPadding, bottom)
    }

    /**
     * Method to process the rectangle where the background (with its padding) will be drawn when the
     * text gravity is center
     * @param left - left coordinate of the textView relative to its parent
     * @param top - top coordinate of the textView relative to its parent
     * @param right - right coordinate of the textView relative to its parent
     * @param bottom - bottom coordinate of the textView relative to its parent
     * @param textWidth - the width of the textView
     *
     * @return Rect - containing the coordinates to draw the background
     */
    private fun getCenterRect(left: Int, top: Int, right: Int, bottom: Int, textWidth: Int): Rect {
        val diff = abs((right - left) / 2 - textWidth / 2)
        return Rect(left + diff - mPadding, top, right - diff + mPadding, bottom)
    }
}

And how to use it:

private fun setBackgroundToTextOnlyInTextView(textView: TextView, text: CharSequence, @ColorRes backgroundColor: Int, @DimenRes paddingID: Int) {
    val padding = context.resources.getDimensionPixelSize(paddingID)

    textView.setShadowLayer(padding.toFloat() , 0.0f, 0.0f, Color.TRANSPARENT )
    textView.setPadding(padding, padding, padding, padding)

    val color = ContextCompat.getColor(context, backgroundColor)
    val spannableString = SpannableString(text)
    val backgroundSpan = PaddingBackgroundColorSpan(color, padding, textView.gravity)
    spannableString.setSpan(backgroundSpan, 0, spannableString.length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
    textView.text = spannableString
}