Kotlin caculator step by step

2023-12-02 13:01:16

1 layout

String

<resources>
    <string name="app_name">Test1</string>
    <string name="calculate">Calculate</string>
    <string name="cost_of_service">Cost of service</string>
    <string name="how_was_the_service">How was the service</string>

    <string name="good_18">Good(18%)</string>
    <string name="ok_15">OK(15%)</string>
    <string name="amazing_20">amazing(20%)</string>
    <string name="round_up_tips">round_up_tips?</string>
    <string name="tip_amount">Tip amount</string>

</resources>

xml 布局文件

<?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">

    <TextView
        android:id="@+id/service_question"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="28dp"

        android:padding="16dp"
        android:text="@string/how_was_the_service"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.064"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/cost_of_service" />

    <Button
        android:id="@+id/calculate_button"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="@string/calculate"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tip_options"
        app:layout_constraintVertical_bias="1.0" />

    <EditText
        android:id="@+id/cost_of_service"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="72dp"
        android:width="460dp"
        android:ems="10"
        android:hint="@string/cost_of_service"

        android:importantForAutofill="no"
        android:inputType="numberDecimal"
        android:minHeight="48dp"
        app:layout_constraintBottom_toTopOf="@+id/service_question"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.047"
        tools:ignore="TextContrastCheck" />

    <RadioGroup
        android:id="@+id/tip_options"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintStart_toStartOf="@+id/service_question"
        app:layout_constraintTop_toBottomOf="@id/service_question">


        <RadioButton
            android:id="@+id/option_twenty_percent"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/amazing_20" />

        <RadioButton
            android:id="@+id/option_eighteen_percent"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/good_18" />

        <RadioButton
            android:id="@+id/option_fifteen_percent"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/ok_15" />

    </RadioGroup>

    <Switch
        android:id="@+id/round_up_switch"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="260dp"
        android:checked="true"
        android:minHeight="48dp"
        android:text="@string/round_up_tips"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/tip_options"
        tools:ignore="UseSwitchCompatOrMaterialXml" />

    <TextView
        android:id="@+id/tip_amount"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/tip_amount"
        android:textSize="26sp"
        app:layout_constraintBottom_toTopOf="@+id/round_up_switch"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.929"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/cost_of_service"
        app:layout_constraintVertical_bias="0.926"
        tools:text="Tip Amount:10$" />


</androidx.constraintlayout.widget.ConstraintLayout>

2 use Binding method

打开应用的 build.gradle 文件 (app)。
在 android 部分中，添加以下代码行：

  // use binding
    buildFeatures {
        viewBinding = true
    }

Then you can use Binding with no error

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.*
import com.example.test1.databinding.ActivityMainBinding

3 Code

I can't use simulator....

Disable the Hyper_V

use other simulator. I don't know why..

Sometimes , bracket {} would affect your result, such as .. onclick, you should use {}

codes are as following!

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
//import android.view.View
//import android.widget.*
import com.example.test1.databinding.ActivityMainBinding
import java.text.NumberFormat

 class MainActivity : AppCompatActivity() {
   lateinit var binding: ActivityMainBinding // lateinit can use variable with no init value


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        binding = ActivityMainBinding.inflate(layoutInflater) //初始化 binding 对象，您将使用该对象访问 activity_main.xml 布局中的 Views

        setContentView(binding.root)//设置 activity 的内容视图,指定应用中视图层次结构的根 binding.root
        binding.calculateButton.setOnClickListener{ caculateTip() }




       // setContentView(binding.root)
       // val button: Button = findViewById(R.id.calculate_button)


      //  button.setOnClickListener{ calculateTip() }


    }

   private fun caculateTip() {
        val StringinTextField=binding.costOfService.text.toString() // get input value
        val cost=StringinTextField.toDouble()
        val selectID=binding.tipOptions.checkedRadioButtonId
        val tipPreference=when (selectID){
            R.id.option_twenty_percent -> 0.20
            R.id.option_eighteen_percent -> 0.18
            else -> 0.15
        }
        var tip=tipPreference*cost
        val roundup=binding.roundUpSwitch.isChecked()
        if (roundup){
            tip=kotlin.math.ceil(tip)// format tip
        }
        val formatTip=NumberFormat.getCurrencyInstance().format(tip)
        binding.tipAmount.text=formatTip    //  //getString(R.string.tip_amount,formatTip)
    }
}

4 use 夜神 simulator instead of inline simulator

any prolem see AS 仿真出错解决

it works

Add your signature. all the parameters are set by the previous step.

signingConfigs {
        debug {
            storeFile file("D:/Work/apk/apk.jks")
            storePassword "800810"
            keyAlias "key0"
            keyPassword "800810"
            v1SigningEnabled true
            v2SigningEnabled true
        }
        release {
            storeFile file("D:/Work/apk/apk.jks")
            storePassword "800810"
            keyAlias "key0"
            keyPassword "800810"
            v1SigningEnabled true
            v2SigningEnabled true
        }
    }

Rotate the screen

it Works!! Awesome

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