Can't set visibility on constraint group

问题

When i try to set the visibility of the group on button click,it doesn't affect the view's visibility.Using com.android.support.constraint:constraint-layout:1.1.0-beta4. I've tried setting it element-wise without problems,but no success with the group.

My MainActivity.kt

private fun toggleLoginUI(show: Boolean) {
    if (show) {
        group.visibility = VISIBLE
    } else {
        group.visibility = INVISIBLE
    }
}

fun onClick(view: View) {
    when (view.id) {
        R.id.button -> toggleLoginUI(true)
        R.id.button4 -> toggleLoginUI(false)
    }
}

My activity_main.xml

    <android.support.constraint.ConstraintLayout..

            <TextView
                android:id="@+id/textView"
... />

            <TextView
                android:id="@+id/textView2"
... />

            <Button
                android:id="@+id/button"
.../>

            <Button
                android:id="@+id/button4"
... />


            <android.support.constraint.Group
                android:id="@+id/group"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:visibility="visible"
                app:constraint_referenced_ids="textView,textView2" />
            </android.support.constraint.ConstraintLayout>

回答1:

This looks like a bug to me. GONE works but INVISIBLE doesn't and I think it should. It may be worth a bug report unless someone can post where my thinking is wrong. (I am using constraint-layout:1.1.0-beta4.)

In the meantime, here is a work-around that explicitly retrieves the ids within the group and sets the visibility of each retrieved view.

Within MainActivity.kt

private fun toggleLoginUI(show: Boolean) {
    if (show) {
        setGroupVisibility(mLayout, group, Group.VISIBLE)
    } else {
        setGroupVisibility(mLayout, group, Group.INVISIBLE)
    }
}

private fun setGroupVisibility(layout: ConstraintLayout, group: Group, visibility: Int) {
    val refIds = group.referencedIds
    for (id in refIds) {
        layout.findViewById<View>(id).visibility = visibility
    }
}

mLayout is the ConstraintLayout.

Update: Here is another work-around that takes advantage of the fact that changing to/from GONE works as expected:

private fun toggleLoginUI(show: Boolean) {
    if (show) {
        group.visibility = GONE
        group.visibility = VISIBLE
    } else {
        group.visibility = GONE
        group.visibility = INVISIBLE
    }
}

回答2:

You can also simply call requestLayout method after changing Group visibility to View.INVISIBLE.

fun makeGroupInvisible(group: Group) {
    group.visibility = View.INVISIBLE
    group.requestLayout()
}

Problem is that android.support.constraint.Group updates visibility of its members in updatePreLayout method which is called from onMeasure in ConstraintLayout.

回答3:

android.support.constraint.Group has a public method

 public void updatePreLayout(ConstraintLayout container) {
   ...
 }

that updates children visibilities, so calling

dataGroup.visibility = if (visible) View.VISIBLE else View.INVISIBLE
dataGroup.updatePreLayout(root)

worked for me

回答4:

Just clean your project or Rebuild your project

回答5:

just add follow line you can change it . so it visible .

group.visibility=ConstraintLayout.GONE

回答6:

Had the same problem and nothing from above helps. My solution was to setVisibility(viewId, ConstraintSet.VISIBLE) inside constraint set and apply that to ConstraintLayout view.

For example:

myContstraintSet.apply {
    setVisibility(firstGroup.id, ConstraintSet.VISIBLE)
    setVisibility(secondGroup.id, ConstraintSet.GONE)

    connect(oneView.id, ConstraintSet.BOTTOM, R.id.secondView, ConstraintSet.TOP)
    clear(anotherView.id, ConstraintSet.TOP)
}
myContstraintSet.applyTo(myConstraintLayout)

来源：https://stackoverflow.com/questions/47865436/cant-set-visibility-on-constraint-group

标签

android

kotlin

android-constraintlayout

kotlin-android-extensions