I am having some problems getting the result I want using RelativeLayout, also wondering if I should also use LinearLayout at the same time. Here is my code:

package me.soft.myapp

import android.content.Context
import android.graphics.Color
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.TypedValue
import android.view.Gravity
import android.view.View
import android.widget.LinearLayout
import android.widget.RelativeLayout
import android.widget.ScrollView
import android.widget.TextView
import androidx.constraintlayout.widget.ConstraintLayout

class MainActivity : AppCompatActivity() {
    lateinit private var constraintLayout: ConstraintLayout

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        constraintLayout = this.findViewById(R.id.activity_main)

        val relatLayOut = RelativeLayout(this)
        relatLayOut.id = View.generateViewId()
        val rllyLOP = RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.MATCH_PARENT,
            RelativeLayout.LayoutParams.MATCH_PARENT)
        relatLayOut.layoutParams = rllyLOP
        constraintLayout.addView(relatLayOut)

        // We define 2 colored stripes and one scroll view.
        val bannerOne = stripe("Hello wonderful world of yours ...",
            Color.rgb(0xEE,0xEE,0x22))
        val bannerTwo = stripe("The purpose of our lives is to be happy.",
            Color.rgb(0x22,0xEE,0xEE))
        val scrolZone = scrollBlock(longNumberString(1000))

        // We add them to the global layout.
        relatLayOut.addView(bannerOne)
        relatLayOut.addView(bannerTwo)
        relatLayOut.addView(scrolZone)

        // Set the layout and order of the components:
        val layoutOption = 2//1

        if (layoutOption == 1) {
            setViewBelow(bannerTwo,bannerOne)
            setViewBelow(scrolZone,bannerTwo)
        }

        if (layoutOption == 2) {
            setViewBelow(scrolZone, bannerOne)
            setViewBelow(bannerTwo, scrolZone)
        }
    }


    fun Int.dpToPixels(context: Context):Float = TypedValue.applyDimension(
        TypedValue.COMPLEX_UNIT_DIP,this.toFloat(),context.resources.displayMetrics
    )


    fun stripe(display:String, bgc: Int): RelativeLayout {
        val lnlyLOP = RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.MATCH_PARENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT)
        val lnlyOut = RelativeLayout(this)
        lnlyOut.id = View.generateViewId()
        lnlyOut.gravity = Gravity.CENTER
        lnlyOut.layoutParams = lnlyLOP
        lnlyOut.setBackgroundColor(bgc)

        val theLabel = TextView(this)
        theLabel.text = display
        theLabel.setTextSize(TypedValue.COMPLEX_UNIT_PX, 25.dpToPixels(this))
        theLabel.gravity = Gravity.CENTER
        lnlyOut.addView(theLabel)
        return lnlyOut
    } /* End of stripe */


    fun scrollBlock(display:String): ScrollView {
        val scrolViw = ScrollView(this)
        scrolViw.id = View.generateViewId()
        val rllyLOP = RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.MATCH_PARENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT
        )
        scrolViw.layoutParams = rllyLOP

        val theLabel = TextView(this)
        theLabel.text = display
        scrolViw.addView(theLabel)

        return scrolViw
    } /* End of scrollBlock */


    fun setViewBelow(theView: View, referView: View) { // To set theView below referView.
        val memoLOP = RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.MATCH_PARENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT)
        memoLOP.addRule(RelativeLayout.BELOW, referView.id)
        theView.layoutParams = memoLOP
    } /* End of setViewBelow */


    fun longNumberString(n:Int): String { // To make a long string of numbers.
        if (n<0) return ""
        var resultStr = "0"
        for (i in 1..n) {resultStr  = "-$i"}
        return resultStr
    } /* End of longNumberString */
}

This code is working as I expect when I use layoutOption = 1. But not when I use layoutOption = 2.

Here what I get on the device for layoutOption = 1 :

Here what I get on the device for layoutOption = 2 :

But here what I expect for layoutOption = 2 :

Obviously I am doing something wrong for the result I want with layoutOption = 2.

Can anyone see where the mistake is?

Here is the XML file, just in case:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/   res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@ id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" />

CodePudding user response：

Since you are using RelativeLayout, you could do something like this to achieve your desired results:

a. Make your bannerTwo bottom align to Parent bottom using LayoutParams#alignParentBottom

b. Make your ScrollView Bottom to be Top of bannerTwo using LayoutParams#layout_above

c. Similarly Make your ScrollView Top to be Bottom of bannerOne using LayoutParams#layout_below

This will lock in the size of the ScrollView between the two banners while making the bannerOne and bannerTwo visible on screen. Hope that helps.

CodePudding user response：

Thanks to the tips provided in Pratik K's answer; here is how I finally solved the problem from the code in the post. I replaced the following lines of code:

    if (layoutOption == 2) {
        setViewBelow(scrolZone, bannerOne)
        setViewBelow(bannerTwo, scrolZone)
    }

by the ones below:

    if (layoutOtion == 2) {
        stickViewAtBottom(bannerTwo)
        setViewBetween(scrolZone,bannerOne,bannerTwo)
     }

Where the two new functions stickViewAtBottom() and setViewBetween() are defined as:

fun stickViewAtBottom(theView: View) { // To set theView at the bottom of its parent.
    val memoLOP = RelativeLayout.LayoutParams(
        RelativeLayout.LayoutParams.MATCH_PARENT,
        RelativeLayout.LayoutParams.WRAP_CONTENT)
    val parentID = (theView.parent as View).id
    memoLOP.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM, parentID)
    theView.layoutParams = memoLOP
} /* End of stickViewAtBottom */


fun setViewBetween(theView: View, aboveView: View, beneathView: View) {
    val memoLOP = RelativeLayout.LayoutParams(
        RelativeLayout.LayoutParams.MATCH_PARENT,
        RelativeLayout.LayoutParams.WRAP_CONTENT)
    memoLOP.addRule(RelativeLayout.BELOW, aboveView.id)
    memoLOP.addRule(RelativeLayout.ABOVE, beneathView.id)
    theView.layoutParams = memoLOP
} /* End of setViewBetween */