java - Android app force closes while going on another activity -


i making android app using android 2.2 , eclipse.

there 2 workflows of app:

wf1: coverpageapp -> loginactivity -> dashboard.

wf2: coverpageapp -> registeractivity -> dashboard.

but click on start button in coverpageapp go on activity, i.e loginactivity, app force closes. have included logcat shows error of null exception , in loginactivity java file points on line 51: btnlinktoregistrscrn = (button) findviewbyid(r.id.linktoregisterscreen);

androidmanifest.xml

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"     package="com.app.android"     android:versioncode="1"     android:versionname="1.0" >      <uses-sdk android:targetsdkversion="15" android:minsdkversion="8" />      <uses-permission android:name="android.permission.access_fine_location" />     <uses-permission android:name="android.permission.internet" />      <application         android:icon="@drawable/ic_launcher"         android:label="@string/app_name" >          <activity             android:enabled="true"             android:name=".pageapp"             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:enabled="true"             android:name=".loginactivity1"             android:label="login activity" >         </activity>          <activity             android:enabled="true"             android:name=".caactivity"             android:label="register activity" >         </activity>          <activity             android:enabled="true"             android:name=".dashboardactivity"             android:label="dashboard activity" >         </activity>      </application>    </manifest> 

pageapp.java

import android.app.activity; import android.os.bundle; //import android.content.context; import android.content.intent; import android.widget.button; import android.view.view;  public class pageapp extends activity {      button startbutton;      /** called when activity first created. */     @override     public void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.coverpage);         addlisteneronbutton();    }       public void addlisteneronbutton() {          //final context context1 = this;          startbutton = (button) findviewbyid(r.id.button1);          startbutton.setonclicklistener(new view.onclicklistener() {              @override             public void onclick(view arg0) {                 intent intent1 = new intent(arg0.getcontext(), loginactivity1.class);              //    intent1.addflags(intent.flag_activity_clear_top);                 startactivity(intent1);                  finish();                 }             });      }  } 

log.java

import android.app.activity; //import android.content.context; import android.content.intent; import android.os.bundle; import android.view.view; //import android.view.view.onclicklistener; import android.widget.button; //import android.widget.textview;   public class log extends activity {      button btnlinktoregistrscrn;     button loginbtn1;      /** called when activity first created. */     @override     public void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);      setcontentview(r.layout.login);      addlisteneronbutton(); //     btnlinktoregistrscrn = (button) findviewbyid(r.id.linktoregisterscreen);      }       public void addlisteneronbutton() {          //final context context2 = this;              loginbtn1 = (button) findviewbyid(r.id.btnlogin);              loginbtn1.setonclicklistener(new view.onclicklistener() {              @override             public void onclick(view arg0) {                  intent intent = new intent(arg0.getcontext(), dashboardactivity.class);                 intent.addflags(intent.flag_activity_clear_top);                          startactivity(intent);                }          });     }       {          // link register screen          btnlinktoregistrscrn = (button) findviewbyid(r.id.linktoregisterscreen);          btnlinktoregistrscrn.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                  intent = new intent(v.getcontext(), caaactivity.class);                //  i.addflags(intent.flag_activity_clear_top);                 startactivity(i);                 }         });       }        } 

logcat

05-31 17:53:19.691: d/androidruntime(1958): shutting down vm 05-31 17:53:19.710: w/dalvikvm(1958): threadid=1: thread exiting uncaught exception (group=0x4001d800) 05-31 17:53:19.730: e/androidruntime(1958): fatal exception: main 05-31 17:53:19.730: e/androidruntime(1958):     @ android.app.activitythread.performlaunchactivity(activitythread.java:2585) 05-31 17:53:19.730: e/androidruntime(1958):     @ android.app.activitythread.handlelaunchactivity(activitythread.java:2679) 05-31 17:53:19.730: e/androidruntime(1958):     @ android.app.activitythread.access$2300(activitythread.java:125) 05-31 17:53:19.730: e/androidruntime(1958):     @ android.app.activitythread$h.handlemessage(activitythread.java:2033) 05-31 17:53:19.730: e/androidruntime(1958):     @ android.os.handler.dispatchmessage(handler.java:99) 05-31 17:53:19.730: e/androidruntime(1958):     @ android.os.looper.loop(looper.java:123) 05-31 17:53:19.730: e/androidruntime(1958):     @ android.app.activitythread.main(activitythread.java:4627) 05-31 17:53:19.730: e/androidruntime(1958):     @ java.lang.reflect.method.invokenative(native method) 05-31 17:53:19.730: e/androidruntime(1958):     @ java.lang.reflect.method.invoke(method.java:521) 05-31 17:53:19.730: e/androidruntime(1958):     @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:868) 05-31 17:53:19.730: e/androidruntime(1958):     @ com.android.internal.os.zygoteinit.main(zygoteinit.java:626) 05-31 17:53:19.730: e/androidruntime(1958):     @ dalvik.system.nativestart.main(native method) 05-31 17:53:19.730: e/androidruntime(1958): caused by: java.lang.nullpointerexception 05-31 17:53:19.730: e/androidruntime(1958):     @ android.app.activity.findviewbyid\untime(1958):  @ java.lang.class.newinstanceimpl(native method) 05-31 17:53:19.730: e/androidruntime(1958):     @ java.lang.class.newinstance(class.java:1429) 05-31 17:53:19.730: e/androidruntime(1958):     @ android.app.instrumentation.newactivity(instrumentation.java:1021) 05-31 17:53:19.730: e/androidruntime(1958):     @ android.app.activitythread.performlaunchactivity(activitythread.java:2577) 05-31 17:53:19.730: e/androidruntime(1958):     ... 11 more 

change loginactivity1 activity as:

public class loginactivity1 extends activity {      button btnlinktoregistrscrn;     button loginbtn1;      /** called when activity first created. */     @override     public void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);      setcontentview(r.layout.login);      addlisteneronbutton();         // link register screen          btnlinktoregistrscrn = (button) findviewbyid(r.id.linktoregisterscreen);          btnlinktoregistrscrn.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                  intent = new intent(v.getcontext(), trekeyesandroidactivity.class);                //  i.addflags(intent.flag_activity_clear_top);                 startactivity(i);                 }         });     }     public void addlisteneronbutton() {          //final context context2 = this;              loginbtn1 = (button) findviewbyid(r.id.btnlogin);              loginbtn1.setonclicklistener(new view.onclicklistener() {              @override             public void onclick(view arg0) {                  intent intent = new intent(arg0.getcontext(), dashboardactivity.class);                 intent.addflags(intent.flag_activity_clear_top);                          startactivity(intent);                }          });     }    } 

and in xml change textview button as

<button          android:id="@+id/linktoregisterscreen"             android:layout_width="fill_parent"             android:layout_height="wrap_content"             android:layout_gravity="center"             android:layout_margintop="25dip"              android:textcolor="#21dbd4"             android:textstyle="bold"              android:text="@string/noaccountregisterme" />   

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