android - my button does nothing (launch new activity clicking in my button) -

when click in button id "faouzi", doesn't work! can me? target show activity named changepassword doesn't launch activity & nothing..

    public class mainactivity extends activity {      sharedpreferences pref;      sharedpreferences prefs;     sharedpreferences preferences;     sharedpreferences.editor editor;      @override     protected void oncreate(bundle savedinstancestate)     {         pref = getsharedpreferences("mypassword",0);         string password = pref.getstring("passwordretrieve", "8888");          super.oncreate(savedinstancestate);         //supprimer la barre de titre de l'activité         requestwindowfeature(window.feature_no_title);         setcontentview(r.layout.activity_main);          //je change la couleur de fond du bouton en bleu          button button = (button)findviewbyid(r.id.connection);         //button.getbackground().setcolorfilter(color.blue, porterduff.mode.multiply);         button.settext(password);          //rendre le bouton "connection" fonctionnel         button.setonclicklistener(new view.onclicklistener() {              public void onclick(view v)              {                 edittext text = (edittext)findviewbyid(r.id.passwordedit);                 string str = text.gettext().tostring();                  if(str.equals("1234"))                 {                     //on va vérifier si l'application déjà été lancée, si c'est le cas on saute certaines étapes d'initialisat°                     preferences = mainactivity.this.getsharedpreferences("nbrepet", mode_private);                           int value = preferences.getint("nbrepet", 0);                     if(value<1)                     {                         sendconnection(v);                     }                     else                     {                         intent intent = new intent(mainactivity.this, regulationtime.class);                         startactivity(intent);                     }                 }                 else                 {                     alertdialog alertdialog = new alertdialog.builder(mainactivity.this).create();                     alertdialog.settitle("wrong password");                     alertdialog.seticon(r.drawable.wrongpassword);                     alertdialog.setmessage("the password entered incorrect, please try again!");                     alertdialog.show();                 }             }         });          //lorsqu'on clique sur le bouton change password         button changepassword = (button)findviewbyid(r.id.faouzi);         changepassword.setonclicklistener(new view.onclicklistener()         {             @override             public void onclick(view v)             {                    intent intent = new intent(mainactivity.this, changepassword.class);                 startactivity(intent);             }         });     }       //fonction appelée pour lancer l'activité "addmasternumber"     public void sendconnection(view v)     {         intent intent = new intent(this, addrecipientnumber.class);         startactivity(intent);  //la nouvelle valeur de "nbrepet" devient 1 & nous empêche de relancer la série d'activités une 2nde fois //l'utilisateur ne doit procéder à certaines étapes 1seule fois (ex: entrer le n° de la socket); on évite cela!         prefs = getsharedpreferences("nbrepet",context.mode_private);         editor = prefs.edit();         editor.putint("nbrepet", 1);         editor.commit();     }  } 

and following xml file layout:

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:paddingbottom="@dimen/activity_vertical_margin"     android:paddingleft="@dimen/activity_horizontal_margin"     android:paddingright="@dimen/activity_horizontal_margin"     android:paddingtop="@dimen/activity_vertical_margin"     tools:context=".mainactivity" >      <textview         android:id="@+id/text1"         android:layout_margintop="20dp"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:textsize="20sp"         android:layout_alignleft="@+id/passwordedit"         android:text="@string/connection" />      <textview          android:id="@+id/text2"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignleft="@+id/passwordedit"         android:layout_below="@+id/text1"         android:text="@string/password"         android:layout_margintop="30dp"    />      <edittext         android:layout_height="wrap_content"         android:layout_width="250dp"         android:layout_centerhorizontal="true"         android:layout_below="@+id/text2"         android:id="@+id/passwordedit"         android:inputtype="numberpassword" />      <button          android:id="@+id/connection"         android:layout_height="wrap_content"         android:layout_width="250dp"         android:layout_below="@+id/passwordedit"         android:layout_margintop="10dp"         android:layout_centerhorizontal="true"         android:onclick="sendconnection"         android:text="@string/connection"   />      <textview         android:id="@+id/defaultpassword"         android:layout_alignleft="@+id/passwordedit"         android:layout_width="fill_parent"         android:layout_margintop="30dp"         android:layout_height="wrap_content"         android:text="@string/defaultpassword"         android:layout_below="@+id/connection" />      <textview         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_centerhorizontal="true"         android:text="@string/change"         android:layout_below="@+id/defaultpassword"         android:id="@+id/change"    />      <button          android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_centerhorizontal="true"         android:onclick="onclick"         android:layout_below="@+id/change"         android:id="@+id/faouzi"         /> </relativelayout> 

and here androidmanifest file:

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"     package="com.example.automatik"     android:versioncode="1"     android:versionname="1.0" >      <uses-sdk         android:minsdkversion="7"         android:targetsdkversion="17" />      <application         android:allowbackup="true"         android:icon="@drawable/ic_launcher"         android:label="@string/app_name"         android:theme="@style/apptheme" >         <activity             android:name="com.example.automatik.mainactivity"             android:label="@string/app_name" >             <intent-filter>                 <action android:name="android.intent.action.main" />                  <category android:name="android.intent.category.launcher" />             </intent-filter>         </activity>         <activity             android:name="com.example.automatik.addmasternumber"             android:label="@string/title_activity_add_master_number"             android:parentactivityname="com.example.automatik.mainactivity" >             <meta-data                 android:name="android.support.parent_activity"                 android:value="com.example.automatik.mainactivity" />         </activity>         <activity             android:name="com.example.automatik.addrecipientnumber"             android:label="@string/title_activity_add_recipient_number"             android:parentactivityname="com.example.automatik.mainactivity" >             <meta-data                 android:name="android.support.parent_activity"                 android:value="com.example.automatik.mainactivity" />         </activity>         <activity             android:name="com.example.automatik.regulationtime"             android:label="@string/title_activity_regulation_time"             android:parentactivityname="com.example.automatik.mainactivity" >             <meta-data                 android:name="android.support.parent_activity"                 android:value="com.example.automatik.mainactivity" />         </activity>         <activity             android:name="com.example.automatik.changepassword"             android:label="@string/title_activity_change_password"             android:parentactivityname="com.example.automatik.mainactivity" >             <meta-data                 android:name="android.support.parent_activity"                 android:value="com.example.automatik.mainactivity" />         </activity>     </application>  </manifest> 

delete line faouzi button in xml:

android:onclick="onclick" 

you either declare button has onclick , use public method in xml or set onclicklistener, not both!