Material-components-android: [MaterialButtonToggleGroup ] Provide switch behavior

[vahid-m]

Currently, the MaterialButtonToggleGroup component can be implemented as only allows one button to be checked by setSingleSelection(true). However, if the user taps again on the checked button it becomes unchecked.
I need a switchable behavior that at any instance only one button is checked and when a user taps again on the checked button nothing occurs. This behavior is more like a switch button.

[Sourav-21]

I need this feature also. But I somehow managed to implement this behaviour by creating custom Buttons for MaterialButtonToggleGroup.

public class ToggleButton extends MaterialButton {
    public ToggleButton(Context context) {
        super(context);
    }

    public ToggleButton(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public ToggleButton(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    public void toggle() {
        if(!isChecked())
            super.toggle();
    }
}

[ferii]

u vx9 9On Jul 14, 2019 8:12 PM, Vahid Mohammadi [e-mail] wrote:Currently, the MaterialButtonToggleGroup component can be implemented as only allows one button to be checked by setSingleSelection(true). However, if the user taps again on the checked button it becomes unchecked.
I need a switchable behavior that at any instance only one button is checked and when a user taps again on the checked button nothing occurs. This behavior is more like a switch button.

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[vahid-m]

I need this feature also. But I somehow managed to implement this behaviour by creating custom Buttons for MaterialButtonToggleGroup.

public class ToggleButton extends MaterialButton {
    public ToggleButton(Context context) {
        super(context);
    }

    public ToggleButton(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public ToggleButton(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    public void toggle() {
        if(!isChecked())
            super.toggle();
    }
}

I do something like you, but I think it's better to handle this behavior by MaterialButtonToggleGroup. I think it can be handled by CheckedStateTrackerclass inside the MaterialButtonToggleGroup class. Unfortunately, most of the methods are private and cannot be overridden.

[StephaneBg]

I manage the case in the listener like that:

  mbtg.addOnButtonCheckedListener { _, checkedId, isChecked ->
            if (isChecked) {
                // do stuff
            } else {
                if (-1 == radioState.checkedButtonId) radioState.check(R.id.defaultButton)
            }
        }

[DroidPulkit]

If we see this :- https://material.io/components/buttons/#toggle-button
In example where the alignment is to set Left, Center or Justify.
We would see, that this feature of selecting the one button at a time is really useful. We should provide this as an option

app:singleSelectionDefaultSelected="@+id/leftAlign"

What do you think @ymarian , does the above use case justify adding the following?

[jda-tid]

I am expecting this feature too.

In my case I am setting the default value at initializacion from sharedPreferences.

However, this feature becomes useful when the selected item is unchecked, which I expect to do nothing and keep the item checked so there is always one checked item.

[ymarian]

Added here:
https://github.com/material-components/material-components-android/commit/a4b90321e32e1dbc0414958bea14a28f9fe68e14