线性布局中的setVisibility和layout_weight之间有什么联系

Question

I have a LinearLayout with three children in it, two RecyclerView s and an ImageView . In the code based on some condition I enable and disable these children using setVisibility() .

public void onNotificationPriorityMixChanged(int mix) {
    Log.d(TAG, "onNotificationPriorityMixChanged() called with: mix = [" + mix + "]");
    switch (mix) {
        case MIX_BOTTOM_ONLY: {
            topListView.setVisibility(GONE);
            bottomListView.setVisibility(VISIBLE);
            spacer.setVisibility(GONE);
        }
        break;
        case MIX_TOP_ONLY: {
            topListView.setVisibility(VISIBLE);
            bottomListView.setVisibility(GONE);
            spacer.setVisibility(GONE);
        }
        break;
        case MIX_NONE: {
            topListView.setVisibility(GONE);
            bottomListView.setVisibility(GONE);
            spacer.setVisibility(GONE);
        }
        break;
        case MIX_BOTH: {
            topListView.setVisibility(VISIBLE);
            bottomListView.setVisibility(VISIBLE);
            spacer.setVisibility(VISIBLE);
        }
        break;
        default:
    }
}

The layout file is has a LinearLayout with a first RecyclerView (topListView) followed by the ImageView (spacer) followed by again a RecyclerView (bottomListView) in it.

The problem is that I cannot get only one child view to occupy whole parent when other two are disabled. My question is that should I use the layout_weight attribute in XML or dynamically. and can anyone tell me what is the connection between using setVisibility() and layout_weight attribute, if there is any?

Answer 1

Set the layout_height of your RecyclerViews to 0dp (for Vertical LinearLayout )

I have tested this working fine

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="2"
    android:orientation="vertical">

    <android.support.v7.widget.RecyclerView
        android:layout_weight="1"
        android:visibility="visible"
        android:layout_width="match_parent"
        android:layout_height="0dp"/>

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="2dp" />

    <android.support.v7.widget.RecyclerView
        android:layout_weight="1"
        android:visibility="visible"
        android:layout_width="match_parent"
        android:layout_height="0dp"/>

</LinearLayout>

for hiding any view use .setVisibility(View.GONE)

for showing any view use .setVisibility(View.VISIBLE)