为啥 TextView 没有显示在应用程序界面上？
Posted
技术标签:
【中文标题】为啥 TextView 没有显示在应用程序界面上？【英文标题】：Why isn't the TextView showing up on the app interface?为什么 TextView 没有显示在应用程序界面上？ 【发布时间】：2021-07-02 13:55:49 【问题描述】：到目前为止，我已经获得了一些帮助，但我仍在尝试将服务成本（可编辑的文本）放入另一个 TextView 中，以便为我的小费计算器显示。代码如下：
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_
android:layout_
android:padding="16dp"
tools:context=".MainActivity">
<ImageView
android:id="@+id/icon_cost_of_service"
android:layout_
android:layout_
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_
android:layout_
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_
android:layout_
android:inputType="numberDecimal"/>
</com.google.android.material.textfield.TextInputLayout>
<ImageView
android:id="@+id/icon_service_question"
android:layout_
android:layout_
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_
android:layout_
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_
android:layout_
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_
android:layout_
android:text="@string/amazing_service" />
<RadioButton
android:id="@+id/option_eighteen_percent"
android:layout_
android:layout_
android:text="@string/good_service" />
<RadioButton
android:id="@+id/option_fifteen_percent"
android:layout_
android:layout_
android:text="@string/ok_service" />
</RadioGroup>
<ImageView
android:id="@+id/icon_round_up"
android:layout_
android:layout_
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_
android:layout_
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_
android:layout_
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_
android:layout_
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_
android:layout_
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：
【问题讨论】：
【参考方案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
【讨论】：
这看起来不错！我添加了代码（做了一些调整），但它现在可以工作了！谢谢：P以上是关于为啥 TextView 没有显示在应用程序界面上？的主要内容，如果未能解决你的问题，请参考以下文章
为啥来自 xml Web 服务的字符串在 Android TextView 中不显示新行？