em kotlin: uma ListView XML array adapter personalizada v4 (destaque)

Posted in arquitecturas móveis (kotlin) - 30/11/2020 - 0 Comment


ficheiro: MainActivity.kt

package pt.deis.estuda.estudoslistview2

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View

const val TAG = "ListView"

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }
    fun onList4View(view: View) {
        val intent = Intent(this,ListView4Activity::class.java)
        startActivity(intent)
    }
}

ficheiro: activity_main.xml

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:onClick="onList4View"
        android:id="@+id/button"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:padding="16dp"
        android:text="ListView XML array adapter personalizado v4"
        android:textSize="24sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

ficheiro: activity_list4_view.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ListView4Activity">

    <ListView
        android:id="@+id/quartaListView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</FrameLayout>

ficheiro: arrays.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="dados_str">
        <item>Portugal</item>
        <item>Espanha</item>
        <item>Franca</item>
        <item>Italia</item>
        <item>Alemanha</item>
        <item>Belgica</item>
        <item>Holanda</item>
        <item>Austria</item>
        <item>Luxemburgo</item>
        <item>Suecia</item>
        <item>Dinamarca</item>
        <item>Irlanda</item>
        <item>Croacia</item>
        <item>Eslovenia</item>
        <item>Eslovaquia</item>
        <item>Estonia</item>
        <item>Polonia</item>
        <item>Grecia</item>
        <item>Finlandia</item>
        <item>Chipre</item>
        <item>Malta</item>
        <item>Bulgaria</item>
        <item>Hungria</item>
        <item>Romenia</item>
        <item>Rep. Checa</item>
        <item>Letonia</item>
        <item>Lituania</item>
    </string-array>
</resources>

ficheiro: AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="pt.deis.estuda.estudoslistview4">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.Estudoslistview4">

        <activity
            android:name=".ListView4Activity"
            android:label="ListView"
            android:parentActivityName=".MainActivity" />

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

ficheiro: ListView4Activity.kt

package pt.deis.estuda.estudolistview4

import android.graphics.Color
import android.os.Bundle
import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.BaseAdapter
import android.widget.ImageView
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_list4_view.*
import kotlin.random.Random

class ListView4Activity : AppCompatActivity() {
    data class Pais (val nome : String, var habitantes:Int)

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_list4_view)

        supportActionBar?.setDisplayHomeAsUpEnabled(true)
        supportActionBar?.subtitle = "Exemplo 4"

        val paises = resources.getStringArray(R.array.dados_str)
        paises.sort()
        val data = arrayListOf&lt;Pais&gt;()
        for(p in paises) {
            val item = Pais(p, Random.nextInt(100000,99000000))
            data.add(item)
        }

        val adapter = MyAdapter(data)
        quartaListView.adapter = adapter

        quartaListView.setOnItemClickListener() {
                parent, view, pos, id -&gt;
            Log.i(TAG, "Item: $pos $id")

        }
    }

    //adapter personalizado derivado do BaseAdapter
    class MyAdapter(val data : ArrayList&lt;Pais&gt;) : BaseAdapter() {
        val imgs = arrayOf(
            android.R.drawable.ic_menu_agenda, android.R.drawable.ic_menu_camera,
            android.R.drawable.ic_menu_call, android.R.drawable.ic_menu_compass
        )
        //sendo MyAdapater abstracta tenho que implementar os 4 próximos métodos

        //método devolve quantos items (usar do construtor do data)
        override fun getCount(): Int = data.size

        //método retorna o elemento de dados que está numa posição
        override fun getItem(position: Int): Any {
            return data[position]
        }

        //método para uma posição indica
        override fun getItemId(position: Int): Long = position.toLong()

        //metodo para retornar uma view, é um layout com tudo preenchido com o que queremos
        //o elemento neste caso é o position
        override fun getView(position: Int, convertView: View?, parent: ViewGroup?): View {
            //fazer o inflate do listview_item
            val view =
                LayoutInflater.from(parent!!.context).inflate(R.layout.listview4_item, parent, false)
            //para preencher os campos
            view.findViewById&lt;TextView&gt;(R.id.tv1).text = data[position].nome
            //usar o tv1 e tv2 para inserir os dados
            view.findViewById&lt;TextView&gt;(R.id.tv2).apply {
                text = data[position].habitantes.toString()
                //filtro dos dados dependendo das cores
                if (data[position].habitantes &gt; 80000000) {
                    setBackgroundColor(Color.rgb(128, 0, 0))
                    setTextColor(Color.WHITE)
                }
                //para reduzir o numero de abitantes quanto se dá um toque
                setOnClickListener {
                    data[position].habitantes = (data[position].habitantes * 0.5).toInt()
                    this@MyAdapter.notifyDataSetChanged()
                }
                //quando se faz o long click reponho o numero de habitantes
                setOnLongClickListener {
                    data[position].habitantes = 99_000_000
                    this@MyAdapter.notifyDataSetChanged()
                    true
                }
            }
            //associo uma imagem, sorteadas
            view.findViewById&lt;ImageView&gt;(R.id.ivImg)
                .setImageResource(imgs[Random.nextInt(imgs.size)])
            return view
        }
    }
}

ficheiro: listview4_item.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="4dp">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:padding="4dp"
        android:background="#800000">
        <ImageView
            android:id="@+id/ivImg"
            android:src="@android:drawable/ic_dialog_map"
            android:layout_width="32dp"
            android:layout_height="32dp" />
        <TextView
            android:textStyle="bold"
            android:padding="4dp"
            android:textSize="20sp"
            android:text="text1"
            android:layout_width="0dp"
            android:layout_weight="2"
            android:layout_height="wrap_content"
            android:id="@+id/tv1"
            android:textColor="#000000"
            android:background="#f0d080"/>
        <TextView
            android:padding="4dp"
            android:textSize="20sp"
            android:gravity="right"
            android:text="text2"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:id="@+id/tv2"
            android:background="#80d0f0"/>
    </LinearLayout>
</FrameLayout>

ficheiro: build.gralde (Module)

plugins {
    id 'com.android.application'
    id 'kotlin-android'
    id 'kotlin-android-extensions' // obrigatorio para aceder aos diferentes layouts sem usar o findId
}
...
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