Mobile Apps 2023W Lecture 18

Code

MainActivity.kt

package carleton.comp2601.historyviewer

import android.net.Uri
import android.os.Bundle
import android.util.Log
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.material.MaterialTheme
import androidx.compose.material.Surface
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.ui.tooling.preview.Preview
import carleton.comp2601.historyviewer.ui.theme.HistoryViewerTheme
import androidx.compose.foundation.lazy.items
import androidx.compose.foundation.text.ClickableText
import androidx.compose.runtime.mutableStateListOf
import androidx.compose.runtime.remember
import androidx.compose.ui.text.AnnotatedString

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        var hnTreeRoot = HNTree()
        hnTreeRoot.add("www.carleton.ca")
        hnTreeRoot.add("www.google.com")
        hnTreeRoot.add("www.cbc.ca.")
        hnTreeRoot.add("www.mit.edu")
        hnTreeRoot.add("www.google.com")


        setContent {
            HistoryViewerTheme {
                // A surface container using the 'background' color from the theme
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colors.background
                ) {
                    Start(hnTreeRoot)
                }
            }
        }
    }
}

@Composable
fun Start(hnTreeRoot: HNTree) {

    val allNodes = remember {
        mutableStateListOf<HNTree>()
    }

    hnTreeRoot.addMyNodes(allNodes)

    LazyColumn {
        item {
            Text(text = "HOSTS:")
        }

        items(allNodes) { child ->
            val spacing = "      ".repeat(child.treeLevel)
            val nodeName = child.hostSuffix
            ClickableText(text = AnnotatedString("$spacing$nodeName"), onClick = {
                child.toggleExpanded()
                allNodes.clear()
                hnTreeRoot.addMyNodes(allNodes)
                Log.d("HistoryViewer","toggled node on $nodeName")
            })
        }
    }
}

HNTree.kt

package carleton.comp2601.historyviewer

import android.util.Log

class HNTree {
    var hostComponent: String = ""
    var hostSuffix: String = ""
    var parent: HNTree = this
    var children: MutableList<HNTree> = mutableListOf()
    var treeLevel: Int = 0
    var expanded = true

    fun add(hostPrefix: String) {
        var allComponents: List<String>
        var component: String
        var child: HNTree? = null

        /* still have to deal with getting to the end */

        allComponents = hostPrefix.split(".")
        if (allComponents.last() == "") {
            allComponents = allComponents.dropLast(1)
        }
        component = allComponents.last()

        for (c in this.children) {
                 if (c.hostComponent == component) {
                     child = c
                     break
                 }
        }

        if (child == null) {
            child = HNTree()
            child.parent = this
            child.hostComponent = component
            child.hostSuffix = "$component.$hostSuffix"
            child.treeLevel = this.treeLevel + 1
            children.add(child)
        }

        val hostRemainder = allComponents.dropLast(1).joinToString(".")

        Log.d("HNTree", "$hostSuffix adding child $hostRemainder")
        if (component != hostPrefix) {
            child.add(hostRemainder)
        }
    }

    fun addMyNodes(nodes: MutableList<HNTree>) {
        nodes.add(this)
        if (expanded) {
            //Log.d("HNTree", "$hostSuffix is expanded " )
            for (n in children) {
                n.addMyNodes(nodes)
            }
        }
        //Log.d("HNTree", "$hostSuffix added " + nodes.count() + " nodes." )
    }

    fun toggleExpanded() {
        expanded = !expanded
    }
}