Estou usando o celular para realizar os testes:

06-29 18:57:59.882: E/AndroidRuntime(7360): FATAL EXCEPTION: main
06-29 18:57:59.882: E/AndroidRuntime(7360): java.lang.IllegalStateException: Could not execute method of the activity
06-29 18:57:59.882: E/AndroidRuntime(7360): at android.view.View$1.onClick(View.java:2144)
06-29 18:57:59.882: E/AndroidRuntime(7360): at android.view.View.performClick(View.java:2485)
06-29 18:57:59.882: E/AndroidRuntime(7360): at android.view.View$PerformClick.run(View.java:9080)
06-29 18:57:59.882: E/AndroidRuntime(7360): at android.os.Handler.handleCallback(Handler.java:587)
06-29 18:57:59.882: E/AndroidRuntime(7360): at android.os.Handler.dispatchMessage(Handler.java:92)
06-29 18:57:59.882: E/AndroidRuntime(7360): at android.os.Looper.loop(Looper.java:130)
06-29 18:57:59.882: E/AndroidRuntime(7360): at android.app.ActivityThread.main(ActivityThread.java:3687)
06-29 18:57:59.882: E/AndroidRuntime(7360): at java.lang.reflect.Method.invokeNative(Native Method)
06-29 18:57:59.882: E/AndroidRuntime(7360): at java.lang.reflect.Method.invoke(Method.java:507)
06-29 18:57:59.882: E/AndroidRuntime(7360): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
06-29 18:57:59.882: E/AndroidRuntime(7360): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
06-29 18:57:59.882: E/AndroidRuntime(7360): at dalvik.system.NativeStart.main(Native Method)
06-29 18:57:59.882: E/AndroidRuntime(7360): Caused by: java.lang.reflect.InvocationTargetException
06-29 18:57:59.882: E/AndroidRuntime(7360): at java.lang.reflect.Method.invokeNative(Native Method)
06-29 18:57:59.882: E/AndroidRuntime(7360): at java.lang.reflect.Method.invoke(Method.java:507)
06-29 18:57:59.882: E/AndroidRuntime(7360): at android.view.View$1.onClick(View.java:2139)
06-29 18:57:59.882: E/AndroidRuntime(7360): ... 11 more
06-29 18:57:59.882: E/AndroidRuntime(7360): Caused by: java.lang.NullPointerException
06-29 18:57:59.882: E/AndroidRuntime(7360): at dominus.vendas.NovaVendaActivity.salvar(NovaVendaActivity.java:48)
06-29 18:57:59.882: E/AndroidRuntime(7360): ... 14 more

Amigo,

Alguma variavel nao esta sendo preenchida, devido o erro Caused by: java.lang.NullPointerException,

Aconselho vc usar o emulador e rodar ele em modo debug, pois vc vai saber qual variavel que nao esta sendo preeenchida.