Android EditText Input Detection

<span id="Label3"></p><p><p>When a feature is recently developed, a story occurs with the following plot:</p></p><p><p>The function is not complex, which requires a edittext to get the information entered by the User. so, I made a dialog to show my input interface (code below):</p></p><p><p></p></p><pre name="code" class="java">Malertdialog = new Alertdialog.builder (this)//, android. R.style.theme_holo_light. SetIcon (r.drawable.ic_dialog_info_light). settitle (r.string.model_ rename_device). setview (createdialogview (devicename)). Setpositivebutton (android. r.string.ok, new Dialoginterface.onclicklistener () {public void OnClick (dialoginterface dialog, int Which) {//string devicename = mdevicenameview.gettext (). toString (); reset_success=false; Reset_model_name (mdevicenameview.gettext (). toString ());//finish (); }}). Setnegativebutton (android. r.string.cancel, new Dialoginterface.onclicklistener () {public void OnClick (Dia Loginterface dialog, int Which) {//finish (); } }). setondismisslistener (new dialoginterface.ondismisslistener () {@Overridepublic void Ondismiss (dialoginterface arg 0) {if (reset_success) {start_confir_resetphone ();} Else{finish ();}}) . Create (); Malertdialog.getwindow (). setsoftinputmode (WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE ); Malertdialog.show ();</pre><br><pre name="code" class="java"> Private View Createdialogview (String devicename) {final layoutinflater layoutinflater = (layoutinflater) This . Getsystemservice (context.layout_inflater_service); View view = Layoutinflater.inflate (r.layout.dialog_edittext, null); Mdevicenameview = (EditText) View.findviewbyid (r.id.edittext); Mdevicenameview.setfilters (new inputfilter[] {new utf8bytelengthfilter (model_name_max_length_bytes) }); Mdevicenameview.settext (devicename); Set initial value before adding listener Mdevicenameview.addtextchangedlistener (this); Mdevicenameview.setoneditoractionlistener (new Textview.oneditoractionlistener () {@Override public b Oolean oneditoraction (TextView v, int actionid, keyevent event) {if (actionid = = Editorinfo.ime_action_don E) {reset_model_name (v.gettext (). toString ()); Malertdialog.dismiss ();//finish (); RetUrn true; Action handled} Else {//finish (); Return false; Not handled}}); mdevicenameview.setselection (mdevicenameview.length ()); Return view; }</pre>It's easy to implement! but when I store the user input string, the problem comes!<p><p></p></p><p><p>Originally the user input string needs to be stored in a section of our own configuration of nv, it is important to give me the space stored in a string of only 20 byte, there is no error is a Byte. So it is easy to enter a character that cannot exceed 20 characters, because it is a byte type, so for the input character must be detected, the character must be in a byte value space (0-127) Inside. actually, it's the ASIC Code.</p></p><p><p>therefore, the input character detection is Required.</p></p><p><p>In order to be able to detect edittext input characters in real time you need to edittext.addtextchangedlistener () to add a textwatcher detector and implement the Method:</p></p><p><p>public void aftertextchanged (Editable S)</p></p><p><p>public void beforetextchanged (charsequence s, int start, int count, Int. After)</p></p><p><p>public void ontextchanged (charsequence s, int start, int before, int Count)</p></p><p><p>The first thing to think of is the Aftertextchanged method to determine whether the current input character is the correct character, if not by editable s to change: S.delete () to Delete. or just use this edittext to start typing the characters from the new Setting. : SetText ();</p></p><p><p>In fact, these two methods are not, when the fast input of the wrong characters will appear abnormal, it is obvious that the problem of Synchronization.</p></p><p><p>Soon i'll give you another solution: in ontextchanged () detects if there are any unusual characters, and if any, it is handled by sending a message in the form of handler.</p></p><p><p></p></p><pre name="code" class="java"><pre name="code" class="java">public void ontextchanged (charsequence s, int. start, int before, int Count) {for (int i=0; i < count; i++) {if (s.charat (i +start) > 127 | | S.charat (i+start) < 0) {Message msg = mhandler.obtainmessage (handlemessage_detection_mg); msg.obj = s; Mhandler.sendmessage (msg); break;}} LOG.D (debug_str, "ontextchanged str=" +s.tostring () + "start=" +start+ "; before=" +before+ "; count=" +count);}</pre></pre><br><pre name="code" class="java"><pre name="code" class="java"> Handler Mhandler = new Handler () {public void handlemessage (Message msg) {switch (msg.what) {case Handlemessage_detec Tion_mg:inpttext_error_correction ((charsequence) msg.obj); break;case handlemessage_blue_name_mg:inpttext_rename_ Blue (String) msg.obj; break;default:break;}} ;</pre></pre><p><p></p></p><p><p></p></p><pre name="code" class="java"><pre name="code" class="java">private void Inpttext_error_correction (charsequence chars) {if (chars! = null) {StringBuilder str_b = new StringBuilder ( chars); char temp;int start_indx = -1;for (int i = 0; i < str_b.length (); I++) {temp = Str_b.charat (i); if (temp > 127 | | Temp < 0) {if (start_indx < 0) {start_indx = i;} Str_b.deletecharat (i);}} Mdevicenameview.settext (str_b.tostring ()); If (start_indx < 0) {start_indx = Mdevicenameview.length ();} Mdevicenameview.setselection (start_indx); Toast.maketext (rename_model_activity.this, getString (r.string.set_name_error_character_notice), Toast.LENGTH_ Short). Show ();}}</pre></pre><br><br>finally, the restrictions on the input characters can be configured by Edittext.setfilters ():<p><p></p></p><p><p></p></p><pre name="code" class="java"><pre name="code" class="java"> Mdevicenameview.setfilters (new inputfilter[] { new Utf8bytelengthfilter (model_name_max_length_bytes) });</pre></pre><br><pre name="code" class="java"><pre name="code" class="java"></pre></pre>For an input error character, the byte returns "" to:<p><p></p></p><p><p>for (int i = start; i < end; i++) {<br>char C = Source.charat (i);<br></p></p><p><p>If (c > 127 | | C < 0) {<br>Return "";<br>}</p></p><p><p>}<br></p></p><p><p><br></p></p><p><p><br></p></p><p><p><br></p></p><p><p>Android EditText Input Detection</p></p></span>