How to programatically select the default Chip in a ChipGroup in Android?

Question

TL;DR - What is the correct way to programatically select a default choice Chip that is a child of a ChipGroup in Android?

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In my android app, I am using com.google.android.material.chip.Chip styled as @style/Widget.MaterialComponents.Chip.Choice components to represent choices of activities a user can select for a given route (think walk, bike, etc)

Because a route can have different types of activities, I insert each type as a different chip programatically into a com.google.android.material.chip.ChipGroup. I also select the default chip as being the first one inserted in the list using the following code during onViewCreated() of my fragment

 private fun setupTypeSelection(types: List<Type>) {
    types.forEach { type ->
        val chip = layoutInflater.inflate(R.layout.chip_type, viewBinding.typeChipGroup, false) as Chip

        chip.tag = type
        /* Init chip text and icon */

        chip.setOnClickListener {
            /* Update selected type */
        }

        if (currentType == null) {
            chip.isSelected = true
            currentType = type
        }

        viewBinding.typeChipGroup.addView(chip)
    }
}

Here's the layout definition of the ChipGroup, where a I set single selection, etc

chip_group_layout.xml

<com.google.android.material.chip.ChipGroup
      android:id="@+id/type_container"

      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_marginTop="@dimen/margin_medium"

      app:chipSpacingHorizontal="@dimen/margin_medium"
      app:selectionRequired="true"
      app:singleLine="true"
      app:singleSelection="true" />

And here is the chip layout

chip_type.xml

<com.google.android.material.chip.Chip xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     xmlns:app="http://schemas.android.com/apk/res-auto"

     style="@style/Widget.MaterialComponents.Chip.Choice"

     android:layout_width="wrap_content"
     android:layout_height="wrap_content"

     app:chipIconEnabled="true" />

The problem I'm facing is that the chip that was set programatically as selected chip.isSelected = true stays selected even after the user selects a different one through UI interaction.

What is the correct way to programatically select a default choice Chip that is a child of a ChipGroup in Android?

score 10 · Accepted Answer · answered May 13 '20 at 04:29

Found my answer.

Use View.generateViewId() and assign the new Id to the newly create chip. Then, add
Add chip to its parent ChipGroup
Check chip view ChipGroup using viewBinding.typeChipGroup.check(id)

This is the final code:

private fun setupTypeSelection(types: List<Trail.Type>) {

    types.forEach { type ->
        val chip = layoutInflater.inflate(R.layout.chip_trail_type, viewBinding.typeContainer, false) as Chip

        chip.id = View.generateViewId()
        /* Set chip details as usual */

        viewBinding.typeContainer.addView(chip)

        if (currentType == null) viewBinding.typeChipGroup.check(chip.id)
    }
}

score 0 · Answer 2 · answered May 13 '20 at 02:30

0

currentType == null condition will be false for next selection. Are you making it null anywhere else?

Use ChipGroup's setOnCheckedChangeListener to check the state of chip selection instead of chip.setOnClickListener

answered May 13 '20 at 02:30

Vel

74
4

currentType is initialised as null, so when the first chip is created, the currentType is set to its type. – Lorenzo Petroli May 13 '20 at 03:35
Thanks for pointing out setOnCheckedChangeListener. That unfortunately, doesn't answer my original question – Lorenzo Petroli May 13 '20 at 03:49

score 0 · Answer 3 · answered Sep 14 '22 at 18:43

0

val chipGroup = findViewById<ChipGroup>(R.id.chip_group)
val tileSize320 = findViewById<Chip>(R.id.tile_size320)
chipGroup.check(tileSize320)

answered Sep 14 '22 at 18:43

Isaac Padberg

200
8

While this code may solve the question, [including an explanation](//meta.stackexchange.com/q/114762) of how and why this solves the problem would really help to improve the quality of your post, and probably result in more up-votes. Remember that you are answering the question for readers in the future, not just the person asking now. Please [edit] your answer to add explanations and give an indication of what limitations and assumptions apply. – Adrian Mole Sep 17 '22 at 21:52

How to programatically select the default Chip in a ChipGroup in Android?

3 Answers3