[md-checkbox] checked and indeterminate state problem.

[joejordanbrown]

Bug

I believe this is a bug.

What is the expected behavior?

If both checked and indeterminate are true and then checked is set to false it should show indeterminate.

What is the current behavior?

If both checked and indeterminate are true and then checked is set to false it should show indeterminate but instead, it shows unchecked.

What are the steps to reproduce?

If you use the toggles you will see the state of the checkbox not being correct against the set values.
https://embed.plnkr.co/v7euQHvzVsAFHNcpsEFo

Which versions of Angular, Material, OS, browsers are affected?

Latest

[jelbourn]

@tinayuangao can you compare this to the native checkbox behavior?

[joejordanbrown]

@jelbourn I've updated the plunker to compare both to make it easier for you to see what's different.

[jelbourn]

That does look like a bug, then.

[tinayuangao]

Checked the native checkbox behavior in the plunker, and not sure whether we should follow it:

When checked = true, indeterminate = true, the box shows - if the values are set programmatically, while it shows ✓ if set checked to true by clicking on the checkbox.

When checked = false, indeterminate = true, the box shows - if the values are set programmatically, while it shows if set checked to false by clicking on the checkbox.

[tinayuangao]

@jelbourn We did this on purpose. Should we change the current behavior?

See checkbox comment on indeterminate:

Whether the checkbox is indeterminate. This is also known as "mixed" mode and can be used to
represent a checkbox with three states, e.g. a checkbox that represents a nested list of
checkable items. Note that whenever checked is set, indeterminate is immediately set to
false. This differs from the web platform in that indeterminate state on native
checkboxes is only remove when the user manually checks the checkbox (rather than setting the
checked property programmatically). However, we feel that this behavior is more accommodating
to the way consumers would envision using this component.

[joejordanbrown]

@tinayuangao if you're saying that when the md-checkbox checked value is set to true that the indeterminate is set to false that's not correct please check the video https://youtu.be/1WA7fpRgqqU

I agree with the comments, especially when all the browsers seem to have a different idea on how the native indeterminate checkbox should work. just that's not how it's currently working

Some pictures may also help.

When both are true

When both are true and then checked is set to false

When both are false and indeterminate is set to true

Now I'm sure you can see the problem?

[tinayuangao]

@joejordanbrown

When both are true

The indeterminate inside MdCheckbox is set to false when setting checked = true. However, it will not emit an event to update the indeterminate outside MdCheckbox. Similar thing happens when you set checked = false in the second case.

One way to solve this issue is to emit event when indeterminate changed.

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}