Button boton;
EditText editText;
TextView textView;
int h=0;
int m=0;


@Override public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.layout_llamadas);

    textView=(TextView)findViewById(R.id.textViewHora);
    final TimePicker timePicker= (TimePicker)findViewById(R.id.timePickerInicio);
     boton=(Button)findViewById(R.id.buttonActHora);
     boton.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
          int hora= timePicker.getCurrentHour();
          int min=timePicker.getCurrentMinute();textView.setText(String.valueOf(hora)+": "+String.valueOf(min)); //aqui me funciona bien

         }
     });
    editText=(EditText)findViewById(R.id.getHora);
    editText.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            showTime();
        }
    });

} public void showTime(){
   AlertDialog.Builder builder= new AlertDialog.Builder(this);
   LayoutInflater inflater = getLayoutInflater();
   builder.setView(inflater.inflate(R.layout.dialog_set_time,null))
           .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
               @Override
               public void onClick(DialogInterface dialog, int i) { // EL PROBLEMA ESTA AQUI
                  final TimePicker timePicker= (TimePicker)findViewById(R.id.timePicker);
                   TextView textView=(TextView)findViewById(R.id.textViewHora);
                        h=timePicker.getCurrentHour();
                        m=timePicker.getCurrentMinute();
                   textView.setText(String.valueOf(h)+": "+String.valueOf(m));  //textView donde pongo la hora

               }
           });
           builder.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() { //esto tambien funciona bien
               @Override
               public void onClick(DialogInterface dialog, int which) {
                   Toast.makeText(getApplicationContext(),"Por favor, seleccione una hora",Toast.LENGTH_SHORT).show();
               }
           });
   AlertDialog alert=builder.create();
   alert.show(); }}`

02-18 17:59:29.750 17266-17266/com.example.andry.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
                                                                             Process: com.example.andry.myapplication, PID: 17266
                                                                             java.lang.NullPointerException
                                                                                 at com.example.andry.myapplication.Activity_llamadas$3.onClick(Activity_llamadas.java:70)
                                                                                 at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:166)
                                                                                 at android.os.Handler.dispatchMessage(Handler.java:110)
                                                                                 at android.os.Looper.loop(Looper.java:193)
                                                                                 at android.app.ActivityThread.main(ActivityThread.java:5299)
                                                                                 at java.lang.reflect.Method.invokeNative(Native Method)
                                                                                 at java.lang.reflect.Method.invoke(Method.java:515)
                                                                                 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:822)
                                                                                 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:638)
                                                                                 at dalvik.system.NativeStart.main(Native Method)