Enables you to set a max height for a linear layout while also using wrap content.. this means the layout will be collapsable but also have height constraints!

max_height_linear_layout.txt

public class MaxHeightLinearLayout extends LinearLayout {

    private int maxHeightDp;

    public MaxHeightLinearLayout(Context context) {
        super(context);
    }

    public MaxHeightLinearLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        final TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.MaxHeightLinearLayout, 0, 0);
        try {
            maxHeightDp = a.getInteger(R.styleable.MaxHeightLinearLayout_maxHeightDp, 0);
        } finally {
            a.recycle();
        }
    }

    public MaxHeightLinearLayout(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int maxHeightPx = ViewUtils.dpToPx(maxHeightDp);
        heightMeasureSpec = MeasureSpec.makeMeasureSpec(maxHeightPx, MeasureSpec.AT_MOST);
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

    public void setMaxHeightDp(int maxHeightDp) {
        this.maxHeightDp = maxHeightDp;
        invalidate();
    }

}

=========================

<MaxHeightLinearLayout
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/buttonsLayout"
    app:maxHeightDp="50">

    <ImageButton
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:id="@+id/button1"
        android:background="@null"
        android:scaleType="centerInside"
        android:layout_weight="1"
        android:padding="5dp"/>

    <ImageButton
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:id="@+id/button2"
        android:background="@null"
        android:layout_weight="1"
        android:scaleType="centerInside"
        android:padding="5dp"/>
<MaxHeightLinearLayout>

=========================

<resources>
    <declare-styleable name="MaxHeightLinearLayout">
        <attr name="maxHeightDp" format="integer" />
    </declare-styleable>
</resources>

ViewUtils.dpToPx(maxHeightDp) causing error

Simple though great. Much appreciated. I have customized it and use it in my code. Thank you!

public class ViewUtils {

	public static int pxToDp(int px) {
		DisplayMetrics displayMetrics = App.getAppContext().getResources().getDisplayMetrics();
		return Math.round(px / (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
	}

	public static int dpToPx(int dp) {
		DisplayMetrics displayMetrics = App.getAppContext().getResources().getDisplayMetrics();
		return Math.round(dp * (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
	}

}

I adapted this for FrameLayout and Kotlin:

class MaxHeightFrameLayout(context: Context, attrs: AttributeSet?) : FrameLayout(context, attrs) {
    private var maxHeightPx = 0

    init {
        val a = context.theme.obtainStyledAttributes(attrs, R.styleable.MaxHeightLinearLayout, 0, 0)
        maxHeightPx = try {
            a.getInteger(R.styleable.MaxHeightLinearLayout_maxHeightPx, 0)
        } finally {
            a.recycle()
        }
    }

    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        super.onMeasure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(maxHeightPx, MeasureSpec.AT_MOST))
    }

    fun setMaxHeightPx(maxHeightPx: Int) {
        this.maxHeightPx = maxHeightPx
        invalidate()
    }
}

Same things in styles.xml:

<resources>
    <declare-styleable name="MaxHeightLinearLayout">
        <attr name="maxHeightDp" format="integer" />
    </declare-styleable>
</resources>