android - 为什么 TextView 没有显示在应用程序界面上？

Question

到目前为止，我已经对此有所帮助，但我仍在尝试将服务成本（可编辑的文本）放入另一个 TextView 中，以便为我的提示计算器显示。这是代码：

MainActivity.kt

package com.example.tiptime

import android.app.Activity
import android.content.Context
import android.os.Bundle
import android.view.MotionEvent
import android.view.View
import android.view.inputmethod.InputMethodManager
import android.widget.EditText
import androidx.appcompat.app.AppCompatActivity
import androidx.fragment.app.Fragment
import com.example.tiptime.databinding.ActivityMainBinding
import java.text.NumberFormat

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding

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

        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        binding.calculateButton.setOnClickListener { calculateTip() }

    }

    fun calculateTip() {
        val stringInTextField = binding.costOfServiceEditText.text.toString()
        val cost = stringInTextField.toDoubleOrNull()
        if (cost == null) {
            binding.tipResult.text = ""
            return
        }

        val tipPercentage = when (binding.tipOptions.checkedRadioButtonId) {
            R.id.option_twenty_percent -> 0.20
            R.id.option_eighteen_percent -> 0.18
            else -> 0.15
        }

        var tip = tipPercentage * cost
        if (binding.roundUpSwitch.isChecked) {
            tip = kotlin.math.ceil(tip)
        }

        val formattedTip = NumberFormat.getCurrencyInstance().format(tip)
        binding.tipResult.text = getString(R.string.tip_amount, formattedTip)





        val editText = findViewById<EditText>(R.id.cost_of_service_edit_text)
        val textValue = editText.text.toString()

        val textView = findViewById<EditText>( R.id.cost_of_service_edit_text )
        textView.setText(textValue)


    }

}

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"
    android:padding="16dp"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/icon_cost_of_service"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:importantForAccessibility="no"
        app:srcCompat="@drawable/ic_store"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="@id/cost_of_service"
        app:layout_constraintBottom_toBottomOf="@id/cost_of_service"/>

    <com.google.android.material.textfield.TextInputLayout
        android:id="@+id/cost_of_service"
        android:layout_width="160dp"
        android:layout_height="wrap_content"
        android:hint="@string/cost_of_service"
        android:layout_marginStart="16dp"
        app:layout_constraintStart_toEndOf="@id/icon_cost_of_service"
        app:layout_constraintTop_toTopOf="parent" >

        <com.google.android.material.textfield.TextInputEditText
            android:id="@+id/cost_of_service_edit_text"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:inputType="numberDecimal"/>
    </com.google.android.material.textfield.TextInputLayout>

    <ImageView
        android:id="@+id/icon_service_question"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:importantForAccessibility="no"
        app:srcCompat="@drawable/ic_service"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="@id/service_question"
        app:layout_constraintBottom_toBottomOf="@id/service_question"/>

    <TextView
        android:id="@+id/service_question"
        style="@style/Widget.TipTime.TextView"
        android:layout_marginTop="16dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/how_was_the_service"
        app:layout_constraintStart_toStartOf="@id/cost_of_service"
        app:layout_constraintTop_toBottomOf="@id/cost_of_service" />

    <RadioGroup
        android:id="@+id/tip_options"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:checkedButton="@id/option_twenty_percent"
        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_service" />

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

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

    <ImageView
        android:id="@+id/icon_round_up"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:importantForAccessibility="no"
        app:srcCompat="@drawable/ic_round_up"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="@id/round_up_switch"
        app:layout_constraintBottom_toBottomOf="@id/round_up_switch"/>


    <com.google.android.material.switchmaterial.SwitchMaterial
        android:id="@+id/round_up_switch"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:checked="true"
        android:text="@string/round_up_tip"
        app:layout_constraintEnd_toEndOf="parent"
        android:layout_marginStart="16dp"
        app:layout_constraintStart_toEndOf="@id/icon_round_up"
        app:layout_constraintTop_toBottomOf="@id/tip_options" />

    <Button
        android:id="@+id/calculate_button"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="@string/calculate"
        android:layout_marginTop="8dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="@id/round_up_switch"
        app:layout_constraintTop_toBottomOf="@id/round_up_switch" />

    <TextView
        android:id="@+id/tip_result"
        style="@style/Widget.TipTime.TextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@id/total"
        tools:text="Tip Amount: $10" />

    <TextView
        android:id="@+id/total"
        style="@style/Widget.TipTime.TextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@id/calculate_button"
        tools:text="Total: $10" />

</androidx.constraintlayout.widget.ConstraintLayout>

字符串.xml

<resources>
    <style name="Widget.TipTime.TextView" parent="Widget.MaterialComponents.TextView">
        <item name="android:minHeight">@dimen/min_text_height</item>
        <item name="android:gravity">center_vertical</item>
        <item name="android:textAppearance">?attr/textAppearanceBody1</item>
        <item name="android:textSize">25sp</item>
    </style>
    
    <style name="Widget.TipTime.CompoundButton.Switch" parent="Widget.MaterialComponents.CompoundButton.Switch">
        <item name="android:minHeight">@dimen/min_text_height</item>
        <item name="android:gravity">center_vertical</item>
        <item name="android:textAppearance">?attr/textAppearanceBody1</item>
    </style>

    <style name="Widget.TipTime.CompoundButton.RadioButton" parent="Widget.MaterialComponents.CompoundButton.RadioButton">
        <item name="android:paddingStart">8dp</item>
        <item name="android:textAppearance">?attr/textAppearanceBody1</item>
    </style>

    <string name="app_name">Tip Time</string>
    <string name="cost_of_service">Cost of Service</string>
    <string name="how_was_the_service">How was the service?</string>
    <string name="amazing_service">Amazing (20%)</string>
    <string name="good_service">Good (18%)</string>
    <string name="ok_service">Okay (15%)</string>
    <string name="round_up_tip">Round up tip?</string>
    <string name="calculate">Calculate</string>
    <string name="tip_amount">Tip Amount: %s</string>
    <string name="total">Total: %s</string>
</resources>

现在的样子：

它应该是什么样子：

标签： androidxmlkotlintextview

Answer 1

您没有通过绑定将总价值放在那里。添加这一行

binding.total.text = getString(R.string.total, totalCost)

这样calculateTip() 看起来像

...
binding.tipResult.text = getString(R.string.tip_amount, formattedTip)
binding.total.text = getString(R.string.total, totalCost) 
...

并应用逻辑从 editText 值 + 提示计算 totalCost。

编辑：格式化