Android Kotlin - Menus e Activities

Afluentes: Dispositivos Móveis

Visual

Nesse exemplo vamos criar um projeto com um Basic Activity, mas vamos limpar ele um pouco e tirar os fragmentos. Vamos trabalhar com multiplas Activities.

Nosso exemplo pronto deve parecer com as imagens abaixo.

strings.xml

1<resources>
2    <string name="app_name">Menu and Activity Test</string>
3    <string name="action_settings">Settings</string>
4    <string name="action_other">Other</string>
5    <string name="name">Name</string>
6    <string name="age">Age</string>
7    <string name="button_execute">Execute</string>
8    <string name="message">Your name is %1$s and your age are %2$s years old.</string>
9</resources>

Menus

menu_main.xml

No menu_main.xml, adiciona-se os novos itens. A informação orderInCategory é a ordem que os itens do meno irão aparecer.

    <item android:id="@+id/action_settings"
          android:title="@string/action_settings"
          android:orderInCategory="100"
          app:showAsAction="never"/>
    <item android:id="@+id/action_other"
          android:title="@string/action_other"
          android:orderInCategory="101"
          app:showAsAction="never"/>

MainActivity.kt

Nos programa kotlin, basta adicionar as ações dentro da opção no when.

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        val myText: TextView = findViewById(R.id.textViewHello)
        return when (item.itemId) {
            R.id.action_settings -> {
                myText.text = "Settings option"
                return true
            }
            R.id.action_other -> {
                myText.text = "Other option"
                return true
            }
            else -> super.onOptionsItemSelected(item)
        }
    }

content_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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <EditText
        android:id="@+id/editTextName"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="116dp"
        android:ems="10"
        android:hint="@string/name"
        android:inputType="textPersonName"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/editTextAge"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="@string/age"
        android:inputType="textPersonName"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editTextName" />

    <TextView
        android:id="@+id/textViewMessage"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="32dp"
        android:textColor="#734BB9"
        android:textScaleX="1.0"
        android:textSize="20sp"
        android:textStyle="normal"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editTextAge" />
</androidx.constraintlayout.widget.ConstraintLayout>

activity_other.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=".OtherActivity">

    <TextView
        android:id="@+id/textViewName"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="36dp"
        android:text="@string/name"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textViewAge"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp"
        android:text="@string/age"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textViewName" />

    <Button
        android:id="@+id/buttonExecute"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="88dp"
        android:text="@string/button_execute"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textViewAge" />
</androidx.constraintlayout.widget.ConstraintLayout>

Kotlin

MainActivity.kt

package com.example.menuteste

import android.app.Activity
import android.content.Intent
import android.os.Bundle
import com.google.android.material.snackbar.Snackbar
import androidx.appcompat.app.AppCompatActivity
import androidx.navigation.ui.AppBarConfiguration
import android.view.Menu
import android.view.MenuItem
import android.widget.EditText
import android.widget.TextView
import androidx.activity.result.contract.ActivityResultContracts
import com.example.menuteste.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {

    private lateinit var appBarConfiguration: AppBarConfiguration
    private lateinit var binding: ActivityMainBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)
        setSupportActionBar(binding.toolbar)

        binding.fab.setOnClickListener { view ->
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                .setAction("Action", null).show()
        }
    }

    override fun onCreateOptionsMenu(menu: Menu): Boolean {
        menuInflater.inflate(R.menu.menu_main, menu)
        return true
    }

    private fun openOtherActivity() {
        val editTextName : EditText = findViewById(R.id.editTextName)
        val editTextAge : EditText = findViewById(R.id.editTextAge)

        val intent = Intent(this, OtherActivity::class.java)
        intent.putExtra("name", editTextName.text.toString())
        intent.putExtra("age", editTextAge.text.toString())
        getResult.launch(intent)
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        return when (item.itemId) {
            R.id.action_settings -> true
            R.id.action_other -> {
                openOtherActivity()
                true
            }
            else -> super.onOptionsItemSelected(item)
        }
    }

    private val getResult =
        registerForActivityResult(
            ActivityResultContracts.StartActivityForResult()
        ) {
            if (it.resultCode == Activity.RESULT_OK) {
                if (it.data != null) {
                    val textViewMessage : TextView = findViewById(R.id.textViewMessage)
                    textViewMessage.text = it.data?.getStringExtra("message")
                }
            }
        }
}

OtherActivity.kt

package com.example.menuteste

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.TextView

class OtherActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_other)

        val textViewName: TextView = findViewById(R.id.textViewName)
        val textViewAge : TextView = findViewById(R.id.textViewAge)

        val bundle = intent.extras
        if (bundle != null) {
            textViewName.text = bundle.getString("name")
            textViewAge.text = bundle.getString("age")
        }

        val buttonExecute: Button = findViewById(R.id.buttonExecute)
        buttonExecute.setOnClickListener {
            val message = getString(R.string.message, textViewName.text, textViewAge.text)
            val data = Intent()
            data.putExtra("message", message)
            setResult(RESULT_OK, data)
            finish()
        }
    }
}