Android TextView: is there a way to force the marquee animation with short text?
Make your own animation.
anim/marquee.xml
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate
android:fromXDelta="100%"
android:toXDelta="-100%"
android:duration="10000"
android:repeatCount="infinite"
android:repeatMode="restart"
android:interpolator="@android:anim/linear_interpolator"/>
</set>
and in your activity,
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_activity);
TextView myTextView = (TextView) findViewById(R.id.myTextView);
Animation marquee = AnimationUtils.loadAnimation(this, R.anim.marquee);
myTextView.startAnimation(marquee);
}
Taking @JodiMiddleton's suggestion about padding the text I constructed a few helper methods to pad the text to a target width based on a TextPaint object (ensuring correct sizing from fonts etc when measuring):
/**
* Pad a target string of text with spaces on the right to fill a target
* width
*
* @param text The target text
* @param paint The TextPaint used to measure the target text and
* whitespaces
* @param width The target width to fill
* @return the original text with extra padding to fill the width
*/
public static CharSequence padText(CharSequence text, TextPaint paint, int width) {
// First measure the width of the text itself
Rect textbounds = new Rect();
paint.getTextBounds(text.toString(), 0, text.length(), textbounds);
/**
* check to see if it does indeed need padding to reach the target width
*/
if (textbounds.width() > width) {
return text;
}
/*
* Measure the text of the space character (there's a bug with the
* 'getTextBounds() method of Paint that trims the white space, thus
* making it impossible to measure the width of a space without
* surrounding it in arbitrary characters)
*/
String workaroundString = "a a";
Rect spacebounds = new Rect();
paint.getTextBounds(workaroundString, 0, workaroundString.length(), spacebounds);
Rect abounds = new Rect();
paint.getTextBounds(new char[] {
'a'
}, 0, 1, abounds);
float spaceWidth = spacebounds.width() - (abounds.width() * 2);
/*
* measure the amount of spaces needed based on the target width to fill
* (using Math.ceil to ensure the maximum whole number of spaces)
*/
int amountOfSpacesNeeded = (int)Math.ceil((width - textbounds.width()) / spaceWidth);
// pad with spaces til the width is less than the text width
return amountOfSpacesNeeded > 0 ? padRight(text.toString(), text.toString().length()
+ amountOfSpacesNeeded) : text;
}
/**
* Pads a string with white space on the right of the original string
*
* @param s The target string
* @param n The new target length of the string
* @return The target string padded with whitespace on the right to its new
* length
*/
public static String padRight(String s, int n) {
return String.format("%1$-" + n + "s", s);
}
So when you use the methods based on a TextView you would call:
textView.setText(padText(myTargetString, textView.getPaint(), textView.getWidth()));
It's not elegant and I'm almost certain there's improvements that could be made (not to mention a better way of doing it) but nonetheless I'm using it in my code and it appears to be doing the trick :)
I have found a one line code that will do the trick!
Just repeat your short text few times, or separate them with a long blank space.
activity_main.xml
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ellipsize="marquee"
android:focusable="true"
android:focusableInTouchMode="true"
android:marqueeRepeatLimit="marquee_forever"
android:scrollHorizontally="true"
android:singleLine="true"
android:text=""
android:textColor="#ffffff"/>
MainActivity.java
String shortText = "A short text.";
TextView textView = findViewById(R.id.textView);
textView.setText(shortText + " " + shortText);
// repeat the above concatenation as many as required
// just enough to make it marqueeable for auto scrolling
// or you can just increase the length of the blank space
textView.setSelected(true);