Prevent a crash in the slider widget

The Slider widget will throw an exception if we try to set a value
which does not respect the current step size, and min and max values.

This can happen accidentally, for example when restoing the app's
state from disk.

To prevent similar crashes in the future, this change ensures that
the value is acceptable, and rounds and clamps it if necessary.

app/src/common/shared/com/igalia/wolvic/ui/views/settings/SliderSetting.java

@@ -59,9 +59,9 @@ private void initialize(Context aContext) {
 
         mSlider = findViewById(R.id.settings_slider);
         mSlider.setStepSize(mStepSize);
-        mSlider.setValue(mInitialValue);
         mSlider.setValueFrom(mValueFrom);
         mSlider.setValueTo(mValueTo);
+        mSlider.setValue(adjustValueToSliderRange(mInitialValue));
         mSlider.clearOnChangeListeners();
         mSlider.addOnChangeListener(mInternalOnChangeListener);
 
@@ -81,9 +81,15 @@ public void onValueChange(@NonNull Slider slider, float value, boolean fromUser)
         }
     };
 
+    private float adjustValueToSliderRange(float value) {
+        // Prevent an exception if the value does not respect the step size, and min and max values.
+        float roundedValue = Math.round((value - mValueFrom) / mStepSize) * mStepSize + mValueFrom;
+        return Math.max(mValueFrom, Math.min(mValueTo, roundedValue));
+    }
+
     public void setValue(float value, boolean doApply) {
         mSlider.clearOnChangeListeners();
-        mSlider.setValue(value);
+        mSlider.setValue(adjustValueToSliderRange(value));
         mSlider.addOnChangeListener(mInternalOnChangeListener);
 
         if (mSliderListener != null && doApply) {