java - Null Pointer Exception: Trying to make an android app for 3x3x3 tic tac toe -

i checked logcat , saw nullpointerexception error. beginner @ programming pls me out. last time had similar problem had not initialised array. cant figure out whats wrong time.

package com.example.test2;  import android.app.activity; import android.os.bundle; import android.view.menu; import android.view.view; import android.widget.button; import android.widget.textview;  public class mid extends activity {      char[][][] a=new char[3][3][3];         char b=' ';         int i=0,j=0,k=0,l=0,o=0;     @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.mid);            for(j=0;j<3;j++)         {for(k=0;k<3;k++)         {for(k=0;k<3;k++)         {             a[j][k][l]=' ';         }         }         }         button btnt1 = (button)findviewbyid(r.id.btnt1);         button btnt2 = (button)findviewbyid(r.id.btnt2);         button btnt3 = (button)findviewbyid(r.id.btnt3);         button btnt4 = (button)findviewbyid(r.id.btnt4);         button btnt5 = (button)findviewbyid(r.id.btnt5);         button btnt6 = (button)findviewbyid(r.id.btnt6);         button btnt7 = (button)findviewbyid(r.id.btnt7);         button btnt8 = (button)findviewbyid(r.id.btnt8);         button btnt9 = (button)findviewbyid(r.id.btnt9);         button btnm1 = (button)findviewbyid(r.id.btnm1);         button btnm2 = (button)findviewbyid(r.id.btnm2);         button btnm3 = (button)findviewbyid(r.id.btnm3);         button btnm4 = (button)findviewbyid(r.id.btnm4);         button btnm5 = (button)findviewbyid(r.id.btnm5);         button btnm6 = (button)findviewbyid(r.id.btnm6);         button btnm7 = (button)findviewbyid(r.id.btnm7);         button btnm8 = (button)findviewbyid(r.id.btnm8);         button btnm9 = (button)findviewbyid(r.id.btnm9);         button btnb1 = (button)findviewbyid(r.id.btnb1);         button btnb2 = (button)findviewbyid(r.id.btnb2);         button btnb3 = (button)findviewbyid(r.id.btnb3);         button btnb4 = (button)findviewbyid(r.id.btnb4);         button btnb5 = (button)findviewbyid(r.id.btnb5);         button btnb6 = (button)findviewbyid(r.id.btnb6);         button btnb7 = (button)findviewbyid(r.id.btnb7);         button btnb8 = (button)findviewbyid(r.id.btnb8);         button btnb9 = (button)findviewbyid(r.id.btnb9);         button top = (button)findviewbyid(r.id.top);         button mid = (button)findviewbyid(r.id.mid);         button bot = (button)findviewbyid(r.id.bot);         top.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {                 setcontentview(r.layout.top);         }});         mid.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {                 setcontentview(r.layout.mid);         }});         bot.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {                 setcontentview(r.layout.bot);         }});         btnt1.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {                  if(i%2==1) {b='x';}                  else {b='o';}                  i++;              textview opt1 = (textview)findviewbyid(r.id.btnt1);              opt1.settext(string.valueof(b));a[0][0][0]=b;j=0;k=0;              check(a,j,k,l,o);         }});         btnt2.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opt2 = (textview)findviewbyid(r.id.btnt2);              opt2.settext(string.valueof(b));a[0][0][1]=b;j=0;k=1;              check(a,j,k,l,o);         }});         btnt3.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opt3 = (textview)findviewbyid(r.id.btnt3);              opt3.settext(string.valueof(b));a[0][0][2]=b;j=0;k=2;              check(a,j,k,l,o);         }});         btnt4.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opt4 = (textview)findviewbyid(r.id.btnt4);              opt4.settext(string.valueof(b));a[0][1][0]=b;j=1;k=0;              check(a,j,k,l,o);         }});         btnt5.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opt5 = (textview)findviewbyid(r.id.btnt5);              opt5.settext(string.valueof(b));a[0][1][1]=b;j=1;k=1;              check(a,j,k,l,o);         }});         btnt6.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opt6 = (textview)findviewbyid(r.id.btnt6);              opt6.settext(string.valueof(b));a[0][1][2]=b;j=1;k=2;              check(a,j,k,l,o);         }});         btnt7.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opt7 = (textview)findviewbyid(r.id.btnt7);              opt7.settext(string.valueof(b));a[0][2][0]=b;j=2;k=0;              check(a,j,k,l,o);         }});         btnt8.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opt8 = (textview)findviewbyid(r.id.btnt8);              opt8.settext(string.valueof(b));a[0][2][1]=b;j=2;k=1;              check(a,j,k,l,o);         }});         btnt9.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opt9 = (textview)findviewbyid(r.id.btnt9);              opt9.settext(string.valueof(b));a[0][2][2]=b;j=2;k=2;              check(a,j,k,l,o);         }});         btnm1.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {                  if(i%2==1) {b='x';}                  else {b='o';}                  i++;              textview opm1 = (textview)findviewbyid(r.id.btnm1);              opm1.settext(string.valueof(b));a[1][0][0]=b;j=0;k=0;              check(a,j,k,l,o);         }});         btnm2.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opm2 = (textview)findviewbyid(r.id.btnm2);              opm2.settext(string.valueof(b));a[1][0][1]=b;j=0;k=1;              check(a,j,k,l,o);         }});         btnm3.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opm3 = (textview)findviewbyid(r.id.btnm3);              opm3.settext(string.valueof(b));a[1][0][2]=b;j=0;k=2;              check(a,j,k,l,o);         }});         btnm4.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opm4 = (textview)findviewbyid(r.id.btnm4);              opm4.settext(string.valueof(b));a[1][1][0]=b;j=1;k=0;              check(a,j,k,l,o);         }});         btnm5.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opm5 = (textview)findviewbyid(r.id.btnm5);              opm5.settext(string.valueof(b));a[1][1][1]=b;j=1;k=1;              check(a,j,k,l,o);         }});         btnm6.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opm6 = (textview)findviewbyid(r.id.btnm6);              opm6.settext(string.valueof(b));a[1][1][2]=b;j=1;k=2;              check(a,j,k,l,o);         }});         btnm7.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opm7 = (textview)findviewbyid(r.id.btnm7);              opm7.settext(string.valueof(b));a[1][2][0]=b;j=2;k=0;              check(a,j,k,l,o);         }});         btnm8.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opm8 = (textview)findviewbyid(r.id.btnm8);              opm8.settext(string.valueof(b));a[1][2][1]=b;j=2;k=1;              check(a,j,k,l,o);         }});         btnm9.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opm9 = (textview)findviewbyid(r.id.btnm9);              opm9.settext(string.valueof(b));a[1][2][2]=b;j=2;k=2;              check(a,j,k,l,o);         }});         btnb1.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {                  if(i%2==1) {b='x';}                  else {b='o';}                  i++;              textview opb1 = (textview)findviewbyid(r.id.btnb1);              opb1.settext(string.valueof(b));a[2][0][0]=b;j=0;k=0;              check(a,j,k,l,o);         }});         btnb2.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opb2 = (textview)findviewbyid(r.id.btnb2);              opb2.settext(string.valueof(b));a[2][0][1]=b;j=0;k=1;              check(a,j,k,l,o);         }});         btnb3.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opb3 = (textview)findviewbyid(r.id.btnb3);              opb3.settext(string.valueof(b));a[2][0][2]=b;j=0;k=2;              check(a,j,k,l,o);         }});         btnb4.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opb4 = (textview)findviewbyid(r.id.btnb4);              opb4.settext(string.valueof(b));a[2][1][0]=b;j=1;k=0;              check(a,j,k,l,o);         }});         btnb5.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opb5 = (textview)findviewbyid(r.id.btnb5);              opb5.settext(string.valueof(b));a[2][1][1]=b;j=1;k=1;              check(a,j,k,l,o);         }});         btnb6.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opb6 = (textview)findviewbyid(r.id.btnb6);              opb6.settext(string.valueof(b));a[2][1][2]=b;j=1;k=2;              check(a,j,k,l,o);         }});         btnb7.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opb7 = (textview)findviewbyid(r.id.btnb7);              opb7.settext(string.valueof(b));a[2][2][0]=b;j=2;k=0;              check(a,j,k,l,o);         }});         btnb8.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opb8 = (textview)findviewbyid(r.id.btnb8);              opb8.settext(string.valueof(b));a[2][2][1]=b;j=2;k=1;              check(a,j,k,l,o);         }});         btnb9.setonclicklistener(new view.onclicklistener()         {             public void onclick(view v)             {if(i%2==1) {b='x';}          else {b='o';}          i++;                  textview opb9 = (textview)findviewbyid(r.id.btnb9);              opb9.settext(string.valueof(b));a[2][2][2]=b;j=2;k=2;              check(a,j,k,l,o);         }});         }     public void check(char[][][] a,int j,int k,int l,int o)     {         textview txt = (textview)findviewbyid(r.id.txt);         txt.settext(string.valueof(j)+string.valueof(k));         if(a[i][j][0]==a[i][j][1]&&a[i][j][1]==a[i][j][2]&&a[i][j][0]!=' ') o+=1;         if(a[i][0][k]==a[i][1][k]&&a[i][1][k]==a[i][2][k]&&a[i][0][k]!=' ') o+=1;         if(a[0][j][k]==a[1][j][k]&&a[1][j][k]==a[2][j][k]&&a[0][j][k]!=' ') o+=1;         if(((a[i][0][0]==a[i][1][1]&&a[i][1][1]==a[i][2][2])||(a[i][0][2]==a[i][1][1]&&a[i][1][1]==a[i][2][0]))&&a[i][1][1]!=' ') o+=1;         if(((a[0][j][0]==a[1][j][1]&&a[1][j][1]==a[2][j][2])||(a[0][j][2]==a[1][j][1]&&a[1][j][1]==a[2][j][0]))&&a[1][j][1]!=' ') o+=1;         if(((a[0][j][0]==a[1][j][1]&&a[1][j][1]==a[2][j][2])||(a[0][j][2]==a[1][j][1]&&a[1][j][1]==a[2][j][0]))&&a[1][j][1]!=' ') o+=1;         if(((a[0][0][0]==a[1][1][1]&&a[0][0][0]==a[2][2][2])||(a[0][0][2]==a[1][1][1]&&a[0][0][0]==a[2][2][0])||(a[0][2][0]==a[1][1][1]&&a[0][0][0]==a[2][0][2])||(a[2][0][0]==a[1][1][1]&&a[0][0][0]==a[0][2][2]))&&a[1][1][1]!=' ')  o+=1;          if(o!=0) {txt.settext("gg");}     }     @override     public boolean oncreateoptionsmenu(menu menu) {         // inflate menu; adds items action bar if present.         getmenuinflater().inflate(r.menu.mid, menu);         return true;     }  } 

here logcat:

03-21 16:01:06.955: d/dalvikvm(4465): late-enabling checkjni 03-21 16:01:07.055: d/androidruntime(4465): shutting down vm 03-21 16:01:07.055: w/dalvikvm(4465): threadid=1: thread exiting uncaught exception (group=0x415a1ba8) 03-21 16:01:07.065: e/androidruntime(4465): fatal exception: main 03-21 16:01:07.065: e/androidruntime(4465): process: com.example.test2, pid: 4465 03-21 16:01:07.065: e/androidruntime(4465): java.lang.runtimeexception: unable start activity componentinfo{com.example.test2/com.example.test2.mid}: java.lang.nullpointerexception 03-21 16:01:07.065: e/androidruntime(4465):     @ android.app.activitythread.performlaunchactivity(activitythread.java:2195) 03-21 16:01:07.065: e/androidruntime(4465):     @ android.app.activitythread.handlelaunchactivity(activitythread.java:2245) 03-21 16:01:07.065: e/androidruntime(4465):     @ android.app.activitythread.access$800(activitythread.java:135) 03-21 16:01:07.065: e/androidruntime(4465):     @ android.app.activitythread$h.handlemessage(activitythread.java:1196) 03-21 16:01:07.065: e/androidruntime(4465):     @ android.os.handler.dispatchmessage(handler.java:102) 03-21 16:01:07.065: e/androidruntime(4465):     @ android.os.looper.loop(looper.java:136) 03-21 16:01:07.065: e/androidruntime(4465):     @ android.app.activitythread.main(activitythread.java:5017) 03-21 16:01:07.065: e/androidruntime(4465):     @ java.lang.reflect.method.invokenative(native method) 03-21 16:01:07.065: e/androidruntime(4465):     @ java.lang.reflect.method.invoke(method.java:515) 03-21 16:01:07.065: e/androidruntime(4465):     @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:779) 03-21 16:01:07.065: e/androidruntime(4465):     @ com.android.internal.os.zygoteinit.main(zygoteinit.java:595) 03-21 16:01:07.065: e/androidruntime(4465):     @ dalvik.system.nativestart.main(native method) 03-21 16:01:07.065: e/androidruntime(4465): caused by: java.lang.nullpointerexception 03-21 16:01:07.065: e/androidruntime(4465):     @ com.example.test2.mid.oncreate(mid.java:78) 03-21 16:01:07.065: e/androidruntime(4465):     @ android.app.activity.performcreate(activity.java:5231) 03-21 16:01:07.065: e/androidruntime(4465):     @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1087) 03-21 16:01:07.065: e/androidruntime(4465):     @ android.app.activitythread.performlaunchactivity(activitythread.java:2159) 03-21 16:01:07.065: e/androidruntime(4465):     ... 11 more 03-21 16:04:05.315: d/androidruntime(4667): shutting down vm 03-21 16:04:05.315: w/dalvikvm(4667): threadid=1: thread exiting uncaught exception (group=0x415a1ba8) 03-21 16:04:05.315: e/androidruntime(4667): fatal exception: main 03-21 16:04:05.315: e/androidruntime(4667): process: com.example.test2, pid: 4667 03-21 16:04:05.315: e/androidruntime(4667): java.lang.runtimeexception: unable start activity componentinfo{com.example.test2/com.example.test2.mid}: java.lang.nullpointerexception 03-21 16:04:05.315: e/androidruntime(4667):     @ android.app.activitythread.performlaunchactivity(activitythread.java:2195) 03-21 16:04:05.315: e/androidruntime(4667):     @ android.app.activitythread.handlelaunchactivity(activitythread.java:2245) 03-21 16:04:05.315: e/androidruntime(4667):     @ android.app.activitythread.access$800(activitythread.java:135) 03-21 16:04:05.315: e/androidruntime(4667):     @ android.app.activitythread$h.handlemessage(activitythread.java:1196) 03-21 16:04:05.315: e/androidruntime(4667):     @ android.os.handler.dispatchmessage(handler.java:102) 03-21 16:04:05.315: e/androidruntime(4667):     @ android.os.looper.loop(looper.java:136) 03-21 16:04:05.315: e/androidruntime(4667):     @ android.app.activitythread.main(activitythread.java:5017) 03-21 16:04:05.315: e/androidruntime(4667):     @ java.lang.reflect.method.invokenative(native method) 03-21 16:04:05.315: e/androidruntime(4667):     @ java.lang.reflect.method.invoke(method.java:515) 03-21 16:04:05.315: e/androidruntime(4667):     @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:779) 03-21 16:04:05.315: e/androidruntime(4667):     @ com.android.internal.os.zygoteinit.main(zygoteinit.java:595) 03-21 16:04:05.315: e/androidruntime(4667):     @ dalvik.system.nativestart.main(native method) 03-21 16:04:05.315: e/androidruntime(4667): caused by: java.lang.nullpointerexception 03-21 16:04:05.315: e/androidruntime(4667):     @ com.example.test2.mid.oncreate(mid.java:78) 03-21 16:04:05.315: e/androidruntime(4667):     @ android.app.activity.performcreate(activity.java:5231) 03-21 16:04:05.315: e/androidruntime(4667):     @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1087) 03-21 16:04:05.315: e/androidruntime(4667):     @ android.app.activitythread.performlaunchactivity(activitythread.java:2159) 03-21 16:04:05.315: e/androidruntime(4667):     ... 11 more 

textview opt1 = (textview)findviewbyid(r.id.btnt1); 

casting button textview? delete it, do:

btn1.settext("your text");