android 我的程序崩溃试图计算这平均速度在Kotlin

3htmauhk  于 2023-03-16  发布在  Android
关注(0)|答案(1)|浏览(108)

i'm learning kotlin and i'm trying to make a program that calculates the average speed. my program crashes trying to calculate the average speed in kotlin and i have no idea why it is giving this error and how to fix it.
the error that appears is: E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.activityspeed, PID: 10600 kotlin.UninitializedPropertyAccessException: lateinit property etT0 has not been initialized at com.example.activityspeed.MainActivity.getEtT0(MainActivity.kt:18) at com.example.activityspeed.MainActivity.onClick(MainActivity.kt:44) at android.view.View.performClick(View.java:7125) at android.view.View.performClickInternal(View.java:7102) at android.view.View.access$3500(View.java:801) at android.view.View$PerformClick.run(View.java:27336) at android.os.Handler.handleCallback(Handler.java:883) at android.os.Handler.dispatchMessage(Handler.java:100) at android.os.Looper.loop(Looper.java:214) at android.app.ActivityThread.main(ActivityThread.java:7356) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) I/Process: Sending signal. PID: 10600 SIG: 9 Disconnected from the target VM, address: 'localhost:58784', transport: 'socket'
Kotlin:

package com.example.atividadevelocidade

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.Toast
import androidx.appcompat.widget.AppCompatButton
import androidx.appcompat.widget.AppCompatEditText
import kotlin.math.pow

class MainActivity : AppCompatActivity(), View.OnClickListener {

    lateinit var btCalcularVelo: AppCompatButton
    lateinit var etV1: AppCompatEditText
    lateinit var etV0: AppCompatEditText
    lateinit var etT1: AppCompatEditText
    lateinit var etT0: AppCompatEditText

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

        etV1 = findViewById(R.id.etV1)
        etV0 = findViewById(R.id.etV0)
        btCalcularVelo = findViewById(R.id.btCalcularVelo)

        btCalcularVelo.setOnClickListener(this)

    }

    private fun calcularVelo(v1: Double, v0: Double, t1: Double, t0: Double) : Double{
        if (v1 > 0.0 && v0 >= 0.0 && t1 > 0.0 && t0 >= 0.0) {
            return (((v1 - v0) / (t1 - t0)))
        } else {
            throw IllegalArgumentException("Ta Errado.")
        }
    }

    override fun onClick(v: View?) {
        if(v!!.id == R.id.btCalcularVelo) {
            val v0 = etV0.text.toString().toDouble()
            val v1 = etV1.text.toString().toDouble()
            val t0 = etT0.text.toString().toDouble()
            val t1 = etT1.text.toString().toDouble()

            val resultado = calcularVelo(v1, v0, t1, t0)
            Toast.makeText(this, "A velocidade media é: $resultado", Toast.LENGTH_LONG)
                .show()
        }
    }

}

xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    android:gravity="center"
    tools:context=".MainActivity">

    <androidx.appcompat.widget.AppCompatTextView
        android:id="@+id/tvTitulo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Caluclador de Velocidade media"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />


    <androidx.appcompat.widget.AppCompatTextView
        android:id="@+id/tvV0"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/tvTitulo"
        android:text="Velocidade Inicial:"
        android:layout_marginTop="15dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <androidx.appcompat.widget.AppCompatEditText
        android:id="@+id/etV0"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/tvV0"
        android:scaleX="2"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:ignore="SpeakableTextPresentCheck,TouchTargetSizeCheck" />


    <androidx.appcompat.widget.AppCompatTextView
        android:id="@+id/tvV1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/etV0"
        android:text="Velocidade Final:"
        android:layout_marginTop="25dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <androidx.appcompat.widget.AppCompatEditText
        android:id="@+id/etV1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/tvV1"
        android:scaleX="2"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:ignore="SpeakableTextPresentCheck,TouchTargetSizeCheck" />


    <androidx.appcompat.widget.AppCompatTextView
        android:id="@+id/tvT1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/etV1"
        android:text="Tempo Final:"
        android:layout_marginTop="25dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <androidx.appcompat.widget.AppCompatEditText
        android:id="@+id/etT1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/tvT1"
        android:scaleX="2"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:ignore="SpeakableTextPresentCheck,TouchTargetSizeCheck" />



    <androidx.appcompat.widget.AppCompatTextView
        android:id="@+id/tvT0"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/etT1"
        android:text="Tempo Inicial:"
        android:layout_marginTop="15dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <androidx.appcompat.widget.AppCompatEditText
        android:id="@+id/etT0"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/tvT0"
        android:scaleX="2"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:ignore="SpeakableTextPresentCheck,TouchTargetSizeCheck" />


    <androidx.appcompat.widget.AppCompatButton
        android:id="@+id/btCalcularVelo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/etT0"
        android:text="Calcular"
        android:layout_marginTop="15dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</RelativeLayout>
android

1条答案

按热度按时间
zbq4xfa0

zbq4xfa01#

根据您得到这个错误：
属性etT0尚未在com.example.activityspeed.MainActivity.getEtT0（MainActivity.kt：18）上初始化，位于
和你的准则。
变量“etT0”和“etT1”未在onCreate函数中初始化。
就像你对“etV1”和“etV0”所做的那样。
添加以下两行：

etT1 = findViewById(R.id.etT1)
  etT0 = findViewById(R.id.etT0)

你的onCreate乐趣应该是这样的：

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

        etV1 = findViewById(R.id.etV1)
        etV0 = findViewById(R.id.etV0)

// Add This Two Line

      etT1 = findViewById(R.id.etT1)
      etT0 = findViewById(R.id.etT0)

//
        btCalcularVelo = findViewById(R.id.btCalcularVelo)

        btCalcularVelo.setOnClickListener(this)

    }
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