Android textwatcher monitors input content in edittext and limits the number of input characters

In the layout, edittext is often used in the android layout, and the content entered in edittext is often restricted. We can use textwatcher to observe the content entered in the input box and take notes.

Main layout:

<? XML version = "1.0" encoding = "UTF-8"?> <Linearlayout xmlns: Android = "http://schemas.android.com/apk/res/android" Android: Orientation = "Vertical" Android: layout_width = "Fill_parent" Android: layout_height = "Fill_parent"> <textview Android: Id = "@ + ID/TV" Android: layout_width = "Fill_parent" Android: layout_height = "Wrap_content" Android: textcolor = "@ Android: color/White"Android: ellipsize = "Marquee" Android: focusable = "True" Android: marqueerepeatlimit = "Marquee_forever" Android: focusableintouchmode = "True" Android: scrollhorizontally = "True" Android: Text = "Please input the text:"/> <edittext Android: Id = "@ + ID/ET" Android: layout_width = "Match_parent" Android: layout_height = "Wrap_content" Android: inputtype = "Number"/> </linearlayout>

JavaCode:

 Package  Com. Android. text;  Import  Android. App. activity;  Import  Android. OS. Bundle;  Import  Android. Text. editable;  Import  Android. Text. textwatcher;  Import  Android. util. log;  Import  Android. widget. edittext; Import  Android. widget. textview;  Import  Android. widget. Toast;  Public   Class Textwatcherdemo Extends  Activity {  Private  Textview mtextview;  Private  Edittext medittext;  /**  Called when the activity is first created.  */ @ Override  Public   Void  Oncreate (bundle savedinstancestate ){  Super  . Oncreate (savedinstancestate); setcontentview (R. layout. Main); mtextview = (Textview) findviewbyid (R. Id. TV); medittext = (Edittext) findviewbyid (R. Id. Et); medittext. addtextchangedlistener (mtextwatcher);} textwatcher mtextwatcher = New  Textwatcher (){  Private Charsequence temp;  Private   Int  Editstart;  Private   Int  Editend; @ override  Public   Void Beforetextchanged (charsequence s, Int Arg1, Int  Arg2,  Int  Arg3) {temp =S ;}@ override  Public   Void Ontextchanged (charsequence s, Int Arg1, Int  Arg2,  Int  Arg3) {mtextview. settext (s) ;}@ override  Public   Void  Aftertextchanged (editable s) {editstart = Medittext. getselectionstart (); editend =Medittext. getselectionend ();  If (Temp. Length ()> 10 ) {Toast. maketext (textwatcherdemo.  This  , "The number of words you entered exceeds the limit! " , Toast. length_short). Show (); S. Delete (editstart -1 , Editend );  Int Tempselection = Editstart; medittext. settext (s); medittext. setselection (tempselection );}}};}