fix bug

app/src/main/java/be/lepl1509group13/workoutwarrior/WorkoutActivity.java

@@ -108,7 +108,7 @@ public class WorkoutActivity extends AppCompatActivity {
         TextView countdown_text = findViewById(R.id.workout_timer);
         countdown_text.setVisibility(View.INVISIBLE);
 
-        countdown.cancel();
+        if (countdown != null) countdown.cancel();
 
         if (exerciseIndexToDisplay >= exercises.length) {
             finish();
@@ -151,6 +151,7 @@ public class WorkoutActivity extends AppCompatActivity {
                     next_btn.setVisibility(View.VISIBLE);
                     set_break_btn.setVisibility(View.VISIBLE);
                     displayCustomExercise(exercises);
+                    next_btn.setText("Suivant");
                 }
             };
             countDownBreak.start();
@@ -158,7 +159,7 @@ public class WorkoutActivity extends AppCompatActivity {
             next_btn.setOnClickListener(v -> {
                 countDownBreak.cancel();
                 countDownBreak.onFinish();
-                next_btn.setText("Suivant");
+                //next_btn.setText("Suivant");
                 //next_btn.setOnClickListener(v1 -> displayCustomExercise(exercises));
             });
         }
@@ -187,19 +188,21 @@ public class WorkoutActivity extends AppCompatActivity {
         timer = Integer.parseInt(exercises[exerciseIndexToDisplay][3]) * 1000;
         System.out.println("timer = " + timer);
 
-        //Check if the user click on "start timer"
-        Button launch_timer = findViewById(R.id.launch_timer);
-        launch_timer.setVisibility(View.VISIBLE);
-        launch_timer.setOnClickListener(view -> {
-            TextView countdown_text = findViewById(R.id.workout_timer);
-            countdown_text.setVisibility(View.VISIBLE);
-            countdown = workout_timer(timer);
-            countdown.start();
-            launch_timer.setVisibility(View.INVISIBLE);
-            workout_timer_started = true;
-            workout_timer_counting = true;
-        });
-        timeLeftInMillis = timer;
+        if (timer > 0) {
+            //Check if the user click on "start timer"
+            Button launch_timer = findViewById(R.id.launch_timer);
+            launch_timer.setVisibility(View.VISIBLE);
+            launch_timer.setOnClickListener(view -> {
+                TextView countdown_text = findViewById(R.id.workout_timer);
+                countdown_text.setVisibility(View.VISIBLE);
+                countdown = workout_timer(timer);
+                countdown.start();
+                launch_timer.setVisibility(View.INVISIBLE);
+                workout_timer_started = true;
+                workout_timer_counting = true;
+            });
+            timeLeftInMillis = timer;
+        }
     }