Next button for items xml file - android -

i have xml file 500 texts. have button take sentace random , show it. want add 2 more buttons next , back. take every sentace. code rando button.

final textview tv = (textview) findviewbyid(r.id.quote);         resources res = getresources();         mystring = res.getstringarray(r.array.quote);         string q = mystring[rgenerator.nextint(mystring.length)];         tv.settext(q);         button btn = (button) findviewbyid(r.id.btn);         btn.setonclicklistener(new view.onclicklistener() {              public void onclick(view v) {                 mystring = getresources().getstringarray(r.array.quote);                 string q = mystring[rgenerator.nextint(mystring.length)];                 tv.settext(q);             }         });      } 

what code these buttons? thank you

all code:

import java.util.random;  import android.app.activity; import android.content.context; import android.content.res.resources; import android.os.bundle; import android.support.v7.app.actionbaractivity; import android.view.view; import android.widget.button; import android.widget.linearlayout; import android.widget.textview;  import com.google.android.gms.ads.adrequest; import com.google.android.gms.ads.adsize; import com.google.android.gms.ads.adview;  public class mainactivity extends actionbaractivity {     context context;     private string[] mystring;     private static final random rgenerator = new random();     private adview adview;     int index = 0;     private static final string ad_unit_id = "ca-app-pub-7628432187347131/3277094808";      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);         getsupportactionbar().hide();         // create ad.         adview = new adview(this);         adview.setadsize(adsize.smart_banner);         adview.setadunitid(ad_unit_id);          context = this;         linearlayout layout = (linearlayout) findviewbyid(r.id.ads_lin);         layout.addview(adview);          adrequest adrequest = new adrequest.builder()                 .addtestdevice(adrequest.device_id_emulator)                 .addtestdevice("5b895a3cc0ca50d56506e300a4c8342b")                 .addtestdevice("d039292a1f434c999b21503d63d6fd88")                  .addtestdevice("test_emulator").build();          // start loading ad in background.          adview.loadad(adrequest);         // start loading ad in background.         final textview tv = (textview) findviewbyid(r.id.quote);          resources res = getresources();         mystring = res.getstringarray(r.array.quote);         string q = mystring[rgenerator.nextint(mystring.length)];         tv.settext(q);         button btn = (button) findviewbyid(r.id.btn);         button btnnext = (button) findviewbyid(r.id.btnnext);         button btnpreview = (button) findviewbyid(r.id.btnpreview);         btn.setonclicklistener(new view.onclicklistener() {              public void onclick(view v) {                 mystring = getresources().getstringarray(r.array.quote);                 index = rgenerator.nextint(mystring.length);                 string q = mystring[index];                 tv.settext(q);             }         });          btnnext.setonclicklistener(new view.onclicklistener() {             public void onclick(view v) {                 string q = mystring[index++];                 tv.settext(q);             }         });          btnpreview.setonclicklistener(new view.onclicklistener(){             public void onclick(view v){                 string q = mystring[index--];                         tv.settext(q);             }         });     }      @override     public void onresume() {         super.onresume();         if (adview != null) {             adview.resume();         }     }      @override     public void onpause() {         if (adview != null) {             adview.pause();         }         super.onpause();     }      /** called before activity destroyed. */     @override     public void ondestroy() {         // destroy adview.         if (adview != null) {             adview.destroy();         }         super.ondestroy();     }  } 

no errors, when run app, stopped.

this logcat:

09-20 17:24:53.341: e/dalvikvm(7651): adjustadaptivecoef max=6291456, min=1572864, ut=568 09-20 17:24:54.152: e/androidruntime(7651): fatal exception: main 09-20 17:24:54.152: e/androidruntime(7651): java.lang.runtimeexception: unable start activity componentinfo{com.example.stiaica/com.example.stiaica.mainactivity}: java.lang.classcastexception: android.widget.imageview cannot cast android.widget.button 09-20 17:24:54.152: e/androidruntime(7651):     @ android.app.activitythread.performlaunchactivity(activitythread.java:2245) 09-20 17:24:54.152: e/androidruntime(7651):     @ android.app.activitythread.handlelaunchactivity(activitythread.java:2299) 09-20 17:24:54.152: e/androidruntime(7651):     @ android.app.activitythread.access$700(activitythread.java:150) 09-20 17:24:54.152: e/androidruntime(7651):     @ android.app.activitythread$h.handlemessage(activitythread.java:1280) 09-20 17:24:54.152: e/androidruntime(7651):     @ android.os.handler.dispatchmessage(handler.java:99) 09-20 17:24:54.152: e/androidruntime(7651):     @ android.os.looper.loop(looper.java:137) 09-20 17:24:54.152: e/androidruntime(7651):     @ android.app.activitythread.main(activitythread.java:5283) 09-20 17:24:54.152: e/androidruntime(7651):     @ java.lang.reflect.method.invokenative(native method) 09-20 17:24:54.152: e/androidruntime(7651):     @ java.lang.reflect.method.invoke(method.java:511) 09-20 17:24:54.152: e/androidruntime(7651):     @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:1102) 09-20 17:24:54.152: e/androidruntime(7651):     @ com.android.internal.os.zygoteinit.main(zygoteinit.java:869) 09-20 17:24:54.152: e/androidruntime(7651):     @ dalvik.system.nativestart.main(native method) 09-20 17:24:54.152: e/androidruntime(7651): caused by: java.lang.classcastexception: android.widget.imageview cannot cast android.widget.button 09-20 17:24:54.152: e/androidruntime(7651):     @ com.example.stiaica.mainactivity.oncreate(mainactivity.java:59) 09-20 17:24:54.152: e/androidruntime(7651):     @ android.app.activity.performcreate(activity.java:5283) 09-20 17:24:54.152: e/androidruntime(7651):     @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1097) 09-20 17:24:54.152: e/androidruntime(7651):     @ android.app.activitythread.performlaunchactivity(activitythread.java:2209) 09-20 17:24:54.152: e/androidruntime(7651):     ... 11 more 09-20 17:24:54.252: e/googleplayservicesutil(7651): google play services resources not found. check project configuration ensure resources included. 

i tried change actionbaractivity activity more errors comes up.

now working, buttons working. there problem, when reached @ last sentance , press next button app stopped. same thing first sentance.

logcat:

09-20 18:08:56.915: e/dalvikvm(20667): adjustadaptivecoef max=4194304, min=1048576, ut=568 09-20 18:08:58.937: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:08:59.508: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:08:59.548: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:08:59.568: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:09:31.949: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:09:32.020: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:09:32.040: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:09:32.040: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:10:03.740: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:10:03.841: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:10:03.861: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:10:03.871: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:10:34.871: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:10:34.931: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:10:34.961: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:10:34.961: e/googleplayservicesutil(20667): google play services resources not found. check project configuration ensure resources included. 09-20 18:10:40.226: e/androidruntime(20667): fatal exception: main 09-20 18:10:40.226: e/androidruntime(20667): java.lang.arrayindexoutofboundsexception: length=593; index=593 09-20 18:10:40.226: e/androidruntime(20667):    @ com.example.stiaica.mainactivity$2.onclick(mainactivity.java:73) 09-20 18:10:40.226: e/androidruntime(20667):    @ android.view.view.performclick(view.java:4432) 09-20 18:10:40.226: e/androidruntime(20667):    @ android.view.view$performclick.run(view.java:18338) 09-20 18:10:40.226: e/androidruntime(20667):    @ android.os.handler.handlecallback(handler.java:725) 09-20 18:10:40.226: e/androidruntime(20667):    @ android.os.handler.dispatchmessage(handler.java:92) 09-20 18:10:40.226: e/androidruntime(20667):    @ android.os.looper.loop(looper.java:137) 09-20 18:10:40.226: e/androidruntime(20667):    @ android.app.activitythread.main(activitythread.java:5283) 09-20 18:10:40.226: e/androidruntime(20667):    @ java.lang.reflect.method.invokenative(native method) 09-20 18:10:40.226: e/androidruntime(20667):    @ java.lang.reflect.method.invoke(method.java:511) 09-20 18:10:40.226: e/androidruntime(20667):    @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:1102) 09-20 18:10:40.226: e/androidruntime(20667):    @ com.android.internal.os.zygoteinit.main(zygoteinit.java:869) 09-20 18:10:40.226: e/androidruntime(20667):    @ dalvik.system.nativestart.main(native method) 

you need store generated random in index variable

to move next increment variable

to move decrement it

edit

here how :

        public class mainactivity extends activity {         final int index = 0;         @override         protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         final textview tv = (textview) findviewbyid(r.id.quote);         resources res = getresources();         final mystring = res.getstringarray(r.array.quote);         final string q = mystring[rgenerator.nextint(mystring.length)];         tv.settext(q);         button btnnext = (button) findviewbyid(r.id.btnnext);         button btnprevious = (button) findviewbyid(r.id.btnprevious);         button btn = (button) findviewbyid(r.id.btn);         btnnext.setonclicklistener(new view.onclicklistener() {              public void onclick(view v) {                 string q = mystring[index++];                 tv.settext(q);             }         });          btnprevious.setonclicklistener(new view.onclicklistener() {              public void onclick(view v) {                 string q = mystring[index--];                 tv.settext(q);             }         });         btn.setonclicklistener(new view.onclicklistener() {          public void onclick(view v) {             mystring = getresources().getstringarray(r.array.quote);             index = rgenerator.nextint(mystring.length);             string q = mystring[index];             tv.settext(q);         }     });      }     }}