java - Starting Another Activity - Activity not showing my message -

i'm new android developing have experience python , java, decided want make apps, began tutorial developer.android.com.

i'm in build first app > starting activity section.

i made final step without errors, message type in not showing in second activity created when press send button!

(https://developer.android.com/training/basics/firstapp/starting-activity.html#displaymessage) if click link see tutorial, , scroll down bottom, should see message type should pop up, , bigger font size. message find when type small font, default "hello world!"

here's myactivity.java

    package com.example.android.myfirstapp;  import android.app.fragment; import android.support.v7.app.appcompatactivity; import android.os.bundle; import android.view.menu; import android.view.menuitem; import android.content.intent; import android.view.view; import android.widget.edittext;  public class myactivity extends appcompatactivity {     public final static string extra_message = "com.mycompany.myfirstapp.message";  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_my); }  @override public boolean oncreateoptionsmenu(menu menu) {     // inflate menu; adds items action bar if present.     getmenuinflater().inflate(r.menu.menu_my, menu);     return true; }  @override public boolean onoptionsitemselected(menuitem item) {     // handle action bar item clicks here. action bar     // automatically handle clicks on home/up button, long     // specify parent activity in androidmanifest.xml.     int id = item.getitemid();      //noinspection simplifiableifstatement     if (id == r.id.action_settings) {         return true;     }      return super.onoptionsitemselected(item); }  /* called when user clicks send button */ public void sendmessage(view view) //view must parameter of onclick, view pressed. {     // in response     intent intent = new intent(this, displaymessageactivity.class); //a context first parameter (this used because activity class subclass of context)     edittext edittext = (edittext) findviewbyid(r.id.edit_message);     string message = edittext.gettext().tostring();     intent.putextra(extra_message, message);     startactivity(intent); } 

}

here displaymessageactivity.java

package com.example.android.myfirstapp;  import android.content.intent; import android.support.v7.app.appcompatactivity; import android.os.bundle; import android.view.menu; import android.view.menuitem; import android.widget.textview;  public class displaymessageactivity extends appcompatactivity {  @override public void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);      // message intent     intent intent = getintent();     string message = intent.getstringextra(myactivity.extra_message);      // create text view     textview textview = new textview(this);     textview.settextsize(40);     textview.settext(message);      // set text view activity layout     setcontentview(textview);      }  @override public boolean onoptionsitemselected(menuitem item) {     // handle action bar item clicks here. action bar     // automatically handle clicks on home/up button, long     // specify parent activity in androidmanifest.xml.     int id = item.getitemid();      //noinspection simplifiableifstatement     if (id == r.id.action_settings) {         return true;     }      return super.onoptionsitemselected(item); } 

}

i'm not sure if guys need androidmanifest.xml, activity_my.xml, or strings.xml it's better safe sorry!

androidmanifest.xml below:

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.android.myfirstapp" >  <application     android:allowbackup="true"     android:icon="@mipmap/ic_launcher"     android:label="@string/app_name"     android:theme="@style/apptheme" >     <activity         android:name=".myactivity"         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=".displaymessageactivity"         android:label="@string/title_activity_display_message" >     </activity> </application>  </manifest> 

activity_my.xml below:

<linearlayout 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:orientation = "horizontal">  <edittext      android:id = "@+id/edit_message"     android:layout_weight = "1"     android:layout_width = "0dp"     android:layout_height = "wrap_content"     android:hint = "@string/edit_message"     />  <button      android:layout_width = "wrap_content"     android:layout_height = "wrap_content"     android:text = "@string/button_send"     android:onclick = "sendmessage"     /> 

strings.xml below:

<resources> <string name="app_name">my first app!</string> <string name = "edit_message">enter message!</string> <string name = "button_send">send</string>  <string name="action_settings">settings</string> <string name="title_activity_main">mainactivity</string> <string name="title_activity_display_message">displaymessageactivity</string>  <string name="hello_world">hello</string>  </resources> 

i apologize of things not indented if didn't indent when copy pasted them on here.

if me, appreciate it, can continue becoming android developer!

again, app simple type message , send, see message pop bigger font size in activity. though mine showing default, small-font-sized "hello world!" when new activity pops when press send.

thank time, , sorry long post!

first of all, replace

intent.putextra(extra_message, message); 

with

intent.putextra("extra_message", message); 

in myactivity.java

as first argument putextra() should string name, used further in application. please refer [docs](http://developer.android.com/reference/android/content/intent.html#putextra(java.lang.string, android.os.bundle))

now, in displaymessageactivity.java

write oncreate() follows

@override public void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);      // set parent view     setcontentview(r.layout.disp_msg_layout);      // message intent     intent intent = getintent();     string message = intent.getstringextra("extra_message");      // reference textview , update it's content     textview textview = (textview)findviewbyid(r.id.my_text_view);     textview.settext(message); } 

and declare xml file named disp_msg_layout in layouts , should like

<?xml version="1.0" encoding="utf-8"?> <textview  xmlns:android="http://schemas.android.com/apk/res/android"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:textsize="40sp"            android:id="@+id/my_text_view"/>