Scroll TextView to text position
I want to scroll my TextView to make visible a specific position in the text. How can I do that? I tried bringPointIntoView (int offset) but without success.
Source code:
public class TextScrollActivity extends Activity {
public void onCreate (final Bundle savedInstanceState) {
super.onCreate开发者_StackOverflow中文版 (savedInstanceState);
final int position = 500;
final TextView textView = new TextView (this);
final ScrollView scrollView = new ScrollView (this);
scrollView.addView (textView);
Button button = new Button (this);
button.setText ("Scroll to " + position);
LinearLayout layout = new LinearLayout (this);
layout.setOrientation (LinearLayout.VERTICAL);
layout.addView (scrollView,
new LayoutParams (LayoutParams.FILL_PARENT, 200));
layout.addView (button, new LayoutParams (LayoutParams.FILL_PARENT,
LayoutParams.WRAP_CONTENT));
StringBuilder builder = new StringBuilder ();
for (int i = 0; i < 1000; i++)
builder.append (String.format ("[ %05d ] ", i));
textView.setText (builder);
setContentView (layout);
button.setOnClickListener (new OnClickListener () {
public void onClick (View v) {
System.out.println (textView.bringPointIntoView (position * 10));
// scrollView.scrollTo (0, position * 10); // no
}
});
}
}
For those who have the same problem, I finally made my own implementation of bringPointIntoView:
public static void bringPointIntoView (TextView textView,
ScrollView scrollView, int offset)
{
int line = textView.getLayout ().getLineForOffset (offset);
int y = (int) ((line + 0.5) * textView.getLineHeight ());
scrollView.smoothScrollTo (0, y - scrollView.getHeight () / 2);
}
Don't hesitate if you have a better solution.
Does adding a movement method to the text view solve the problem?
textView.setMovementMethod(new ScrollingMovementMethod());
Just FYI for anyone else with the same problem, on a listView
with large listItems
, the overloaded bringPointIntoView
can be passed a ListView
instead of a ScrollView
and use the ScrollTo
method instead of smoothScrollTo
.
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