How can I change the color of a part of a TextView?

Question

Spannable is more flexible:

String text2 = text + CepVizyon.getPhoneCode() + "\n\n"
            + getText(R.string.currentversion) + CepVizyon.getLicenseText();

Spannable spannable = new SpannableString(text2);

spannable.setSpan(new ForegroundColorSpan(Color.WHITE), text.length(), (text + CepVizyon.getPhoneCode()).length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

myTextView.setText(spannable, TextView.BufferType.SPANNABLE);

If you have static text that needs color, you can add it without any code via the strings file:

<string name="already_have_an_account">Already have an account? <font color='#01C6DB'>Login</font></string>

then

<TextView
    android:layout_width="wrap_content"
    android:layout_height="64dp"
    android:text="@string/already_have_an_account"/>

result

I'm not sure which API versions this works on, but it doesn't work for API 19 that I've tested so far, so probably only some of the most recent API versions support this.

As @hairraisin mentioned in the comments, try using fgcolor instead of color for the font color, then it should work for lower API levels, but need more testing to be sure.

myTextView.setText(Html.fromHtml(text + "<font color=white>" + CepVizyon.getPhoneCode() + "</font><br><br>"
            + getText(R.string.currentversion) + CepVizyon.getLicenseText()));

With regards to Maneesh's answer, this will work but you need to add and escape the quotes for the color attribute.

myTextView.setText(Html.fromHtml(text + "<font color=\"#FFFFFF\">" + CepVizyon.getPhoneCode() + "</font><br><br>"
            + getText(R.string.currentversion) + CepVizyon.getLicenseText()));

Here solution in Kotlin that uses SpannableString to change color of part of a string.

    val phoneCodeColor = ContextCompat.getColor(this, R.color.myColor)
    val text = SpannableStringBuilder()
        .color(phoneCodeColor) { append("${ CepVizyon.getPhoneCode() }") }
        .append("\n\n")
        .append(getString(R.string.currentversion))
        .append(${ CepVizyon.getLicenseText() })

    activationText.text = text
    myTextView.text = text

It is good for me!

            Spannable spannable = new SpannableString("ABC In-Network DEF");
            String str = spannable.toString();
            iStart = str.indexOf("In-Network");
            iEnd = iStart + 10;/*10 characters = in-network. */

            SpannableString ssText = new SpannableString(spannable);
            ClickableSpan clickableSpan = new ClickableSpan() {
                @Override
                public void onClick(View widget) {
                    //your code at here.
                }

                @Override
                public void updateDrawState(TextPaint ds) {
                    super.updateDrawState(ds);
                    ds.setUnderlineText(true);
                    ds.setColor(getResources().getColor(R.color.green));
                }
            };
            ssText.setSpan(clickableSpan, iStart, iEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
            mTextView.setText(ssText);
            mTextView.setMovementMethod(LinkMovementMethod.getInstance());
            mTextView.setHighlightColor(Color.TRANSPARENT);
            mTextView.setEnabled(true);

Here's a colorize function based on andyboot's answer:

 /**
 * Colorize a specific substring in a string for TextView. Use it like this: <pre>
 * textView.setText(
 *     Strings.colorized("The some words are black some are the default.","black", Color.BLACK),
 *     TextView.BufferType.SPANNABLE
 * );
 * </pre>
 * @param text Text that contains a substring to colorize
 * @param word The substring to colorize
 * @param argb The color
 * @return the Spannable for TextView's consumption
 */
public static Spannable colorized(final String text, final String word, final int argb) {
    final Spannable spannable = new SpannableString(text);
    int substringStart=0;
    int start;
    while((start=text.indexOf(word,substringStart))>=0){
        spannable.setSpan(
                new ForegroundColorSpan(argb),start,start+word.length(),
                Spannable.SPAN_EXCLUSIVE_EXCLUSIVE
        );
        substringStart = start+word.length();
    }
    return spannable;
}