Disable focus on fragment

Question

I'm working on application for TV platform and use RCU for navigation.

I have use case where I have two fragments one above each other and visible on the screen at the same time.

Is there a way to disable focusing fragment that is below? setFocusable(false) on fragments view doesnt work, and I'm able to focus elements in fragment below.

Thanks in advance.

Swahili

you can add setonclicklistner in onCreate programmatically. – Meddle

something like this. https://mcmap.net/q/1166651/-how-to-remove-the-focus-of-the-back-stack-fragment – Meddle

Why onClickListener? I need something like onFocusChanged? I dont use touch events, it is Android TV with remote controller. – Swahili

@Swahili Can you find a solution? I have the same problem – Engine

@Engine I have posted solution that I've ended up using. – Swahili

Answer 1

The solution that I've come up with in the end is:

Added custom Lifecycle listeners for the fragment namely: onFragmentResume and onFragmentPause events which I call manually when I need to show/hide or switch between fragments.

@Override
public void onFragmentResume() {

    //Enable focus
    if (getView() != null) {

        //Enable focus
        setEnableView((ViewGroup) view, true);

        //Clear focusable elements
        focusableViews.clear();
    }

    //Restore previous focus
    if (previousFocus != null) {
        previousFocus.requestFocus();
    }
}

@Override
public void onFragmentPause() {

    //Disable focus and store previously focused
    if (getView() != null) {

        //Store last focused element
        previousFocus = getView().findFocus();

        //Clear current focus
        getView().clearFocus();

        //Disable focus
        setEnableView((ViewGroup) view, false);
    }
}

/**
 * Find focusable elements in view hierarchy
 *
 * @param viewGroup view
 */
private void findFocusableViews(ViewGroup viewGroup) {

    int childCount = viewGroup.getChildCount();
    for (int i = 0; i < childCount; i++) {
        View view = viewGroup.getChildAt(i);
        if (view.isFocusable()) {
            if (!focusableViews.contains(view)) {
                focusableViews.add(view);
            }
        }
        if (view instanceof ViewGroup) {
            findFocusableViews((ViewGroup) view);
        }
    }
}

/**
 * Enable view
 *
 * @param viewGroup
 * @param isEnabled
 */
private void setEnableView(ViewGroup viewGroup, boolean isEnabled) {

    //Find focusable elements
    findFocusableViews(viewGroup);

    for (View view : focusableViews) {
        view.setEnabled(isEnabled);
        view.setFocusable(isEnabled);
    }
}

Swahili

Answer 2

I had the same problem and the accepted answer worked for me.

Here is my version of the implementation so far (it can be improved):

abstract class BaseFragment<....> : Fragment() {

    private val screenFocusHelper = ScreenFocusHelper()

    fun enableFocus() {
        if (view != null) {
            // Enable focus
            screenFocusHelper.setEnableView(view as ViewGroup, true)

            // Clear focusable elements
            screenFocusHelper.focusableViews.clear()
        }

        childFragmentManager.fragments.forEach {
            if (it is BaseFragment<*, *>) {
                it.enableFocus()
            }
        }
    }

    fun disableFocus() {
        if (view != null) {
            // Store last focused element
            screenFocusHelper.previousFocus = view?.findFocus()

            // Clear current focus
            view!!.clearFocus()

            // Disable focus
            screenFocusHelper.setEnableView(view as ViewGroup, false)
        }

        childFragmentManager.fragments.forEach {
            if (it is BaseFragment<*, *>) {
                it.disableFocus()
            }
        }
    }

}

class ScreenFocusHelper {

    var previousFocus: View? = null

    val focusableViews: MutableList<View> = mutableListOf()

    fun setEnableView(viewGroup: ViewGroup, isEnabled: Boolean) {
        findFocusableViews(viewGroup)

        for (view in focusableViews) {
            view.isEnabled = isEnabled
            view.isFocusable = isEnabled
        }
    }

    private fun findFocusableViews(viewGroup: ViewGroup) {
        val childCount = viewGroup.childCount
        for (i in 0 until childCount) {
            val view = viewGroup.getChildAt(i)
            if (view.isFocusable) {
                if (!focusableViews.contains(view)) {
                    focusableViews += view
                }
            }
            if (view is ViewGroup) {
                findFocusableViews(view)
            }
        }
    }

}

Chloral

Answer 3

This is my solution based on the GuidedStepFragment from leanback, that will block any focus on the view that is not a child of your layout.

Create a custom view and make it as a root layout for the second Fragment that is on the top:

import android.R.attr
import android.content.Context
import android.util.AttributeSet
import android.view.View
import android.view.ViewGroup
import androidx.constraintlayout.widget.ConstraintLayout

class GuidedConstraintLayout @JvmOverloads constructor(
    context: Context,
    attrs: AttributeSet? = null,
    defStyleAttr: Int = 0
) : ConstraintLayout(context, attrs, defStyleAttr) {

private var mFocusOutStart = false
private var mFocusOutEnd = false

fun setFocusOutStart(focusOutStart: Boolean) {
    mFocusOutStart = focusOutStart
}

fun setFocusOutEnd(focusOutEnd: Boolean) {
    mFocusOutEnd = focusOutEnd
}

override fun focusSearch(focused: View?, direction: Int): View? {
    val newFocus = super.focusSearch(focused, direction)
    if (direction == FOCUS_LEFT || direction == FOCUS_RIGHT || direction == FOCUS_UP || direction == FOCUS_DOWN) {
        if (isDescendant(this, newFocus)) {
            return newFocus
        }
        if (if (layoutDirection == LAYOUT_DIRECTION_LTR) attr.direction == FOCUS_LEFT else attr.direction == FOCUS_RIGHT) {
            if (!mFocusOutStart) {
                return focused
            }
        } else {
            if (!mFocusOutEnd) {
                return focused
            }
        }
    }
    return newFocus
}

private fun isDescendant(parent: ViewGroup, child: View?): Boolean {
    var localChild = child
    while (localChild != null) {
        if (localChild === parent) {
            return true
        }
        val p = localChild.parent
        if (p !is View) {
            return false
        }
        localChild = p
    }
    return false
}
}

Manolo

Answer 4

I solved this making a custom class for the parent ViewGroup of the fragment layout. In your custom ViewGroup you can override the method

focusSearch(focused: View?, direction: Int)

Adding this logic:

override fun focusSearch(focused: View?, direction: Int): View? {

        val focusSearch = super.focusSearch(focused, direction)

        if (direction == View.FOCUS_DOWN) when (focused?.id) {
            R.id.some_view_that_has_focus -> return new_view_focus
        }

        if (findViewById<View>(focusSearch.id) == null) {//the view found is not part of this parent return null
            return null
        }

        return focusSearch
}

When the new focused view is not part of this parent than return null. When some other Views focus is not reachable I manage it manually inside when cases.

Gusgusba