无法识别EditText变量的值（appcompat错误）并无法成功转换编辑文本

时间：2018-10-17 16:48:43

标签： java android android-studio android-edittext android-appcompat

我目前正在尝试弄清楚如何查看编辑文本变量的值。在我的代码中，我试图获取用户输入的数字并对其应用数学运算以产生小费计算器。唯一的问题是，如果用户未输入任何要用于初始化的Edit Text变量的值，则Edit Text变量的值将不为null或什至为空字符串，而是此处列出的冗长的代码行： android.support.v7.widget.AppCompatEditText {1b372dd VFED..CL。 ......一世。 0,0-0,0＃7f07009b app：id / userInput}

这是名为userInputAmount的Edit Text变量的值，该变量已使用带有参数（R.id.userInput）的findViewById方法初始化

但是发生错误，当我尝试通过使用Double将那个Edit Text变量 userInputAmount 的值绑定到双精度值 userAmount 时带有参数（.userInputAmount.getText（）。toString（））的.parseDouble方法

我之所以需要真正识别EditText的值，是为了使我可以绕过双重转换，从而不会使我的应用程序崩溃。

我想做的是这个

if(editTextVariable != null && editTextVariable != "")

//Do the double conversion

else

//set the double variable equal to 0 so it wont crash the app.

TLDR：如果值是 android.support.v7.widget.AppCompatEditText {1b372dd VFED..CL，我需要弄清楚Edit Text的值，以便创建一个逻辑门来绕过转换。 ......一世。 0,0-0,0＃7f07009b app：id / userInput} 如果值是那个，我也不想将其初始化为编辑文本变量。我在想也许在初始化之前用if语句检查xml引用（userInput）的值，但是我不知道该怎么做。

此语句出现错误

userAmount = Double.parseDouble(userInputAmount.getText().toString());

下面是代码和xml 

package com.example.frankbuddy.advancedtipcalculator;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.EditText;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;
import android.graphics.Color;



public class MainActivity extends AppCompatActivity {

SeekBar tipSeekBar;
int seekBarValue;

//For custom tip percentage ($%)
TextView tipDisplay;

//For applied custom percentage to user input (#.#$)
TextView tipAmountDisplay;

//For 15% tip
TextView defTipAmount;

//For Default 15% tip total amount
TextView defTotalAmount;

//For Custom % tip total amount
TextView mainTotalAmount;

//For user input amount
EditText userInputAmount;


double userAmount;

double defaultTip;

double defaultTotal;

double userTotalTip;

double userCustomTotal;

private final int ORANGE = 0xFFFF3300;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    //Initialize custom percentage display amount
    tipDisplay = (TextView) findViewById(R.id.tipDisplayPercentage);
    //Intialize user input amount edit text
    userInputAmount =(EditText)findViewById(R.id.userInput);
    //Initialize tip amount display
    tipAmountDisplay = (TextView)findViewById(R.id.tipDisplayAmount);
    //Initialize default tip amount
    defTipAmount = (TextView)findViewById(R.id.defaultTipAmount);
    //Initialize default total amount
    defTotalAmount = (TextView)findViewById(R.id.defaultTotalAmount);
    //Initialize custom total amount
    mainTotalAmount = (TextView)findViewById(R.id.customTotalAmount);

    userTotalTip = 0.0;

    userCustomTotal = 0.0;

    defaultTotal = 0;

    defaultTip = 0;

    userAmount = 0;





    //Seek Bar initialize
    tipSeekBar = (SeekBar)findViewById(R.id.seekBar);
    tipSeekBar.setMax(100);
    tipSeekBar.setProgress(15);

    //Display initial custom tip amount (Default 15%)
    tipDisplay.setTextColor(Color.GREEN);
    tipDisplay.setText(tipSeekBar.getProgress() + "%");


    //Seek bar listener
    tipSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
        //initialize progress value (To be used for display and math)
        int progressChangedValue = 0;


        //Realtime listener for updates
        public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)
        {
            //Set progress changed value
            progressChangedValue = progress ;

            //Update custom display percentage amount
            tipDisplay.setText(progressChangedValue + "%");


            if(progressChangedValue <= 20)
            {
                tipDisplay.setTextColor(Color.GREEN);
            }
            if(progressChangedValue >= 21 && progressChangedValue <= 29)
            {
                tipDisplay.setTextColor(Color.YELLOW);
            }
            //Display warning if progress value meets or exceeds 30%
            if(progressChangedValue >= 30)
            {
                Toast.makeText(MainActivity.this, "Warning, Tip is now exceeding 30% and the value is now " + progressChangedValue + "%",
                        Toast.LENGTH_SHORT).show();

                tipDisplay.setTextColor(Color.RED);
            }



            //Bind user input amount into a double variable to apply mathematics
            userAmount = Double.parseDouble(userInputAmount.getText().toString());

            //Do math for custom tip amount
            userTotalTip = userAmount * progressChangedValue *.01;
            tipAmountDisplay.setText(String.format("%.2f", userTotalTip));

            //Do math for custom total amount
            userCustomTotal = userTotalTip + userAmount;
            mainTotalAmount.setText(String.format("%.2f", userCustomTotal));


            //Do math for default tip amount
            defaultTip = userAmount * .15;
            defTipAmount.setText(String.format("%.2f", defaultTip));

            //Do math for default total amount
            defaultTotal = defaultTip + userAmount;
            defTotalAmount.setText(String.format("%.2f",defaultTotal ));

        }

        //Listener for first changes
        public void onStartTrackingTouch(SeekBar seekBar)
        {

        }

        //Listener for when the user stops manipulating the bar
        public void onStopTrackingTouch(SeekBar seekBar)
        {


        }

    });
}

和XML：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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:background="@android:color/darker_gray"
tools:context=".MainActivity">

<TextView
    android:id="@+id/tipDisplayAmount"
    android:layout_width="76dp"
    android:layout_height="31dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="12dp"
    android:layout_marginEnd="8dp"
    android:textSize="18sp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.555"
    app:layout_constraintStart_toEndOf="@+id/defaultTipAmount"
    app:layout_constraintTop_toBottomOf="@+id/tipDisplayPercentage" />

<TextView
    android:id="@+id/textView4"
    android:layout_width="123dp"
    android:layout_height="31dp"
    android:layout_marginStart="20dp"
    android:layout_marginTop="24dp"
    android:layout_marginBottom="8dp"
    android:text="Total"
    android:textAlignment="center"
    android:textSize="20sp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textView3"
    app:layout_constraintVertical_bias="0.011" />

<TextView
    android:id="@+id/textView"
    android:layout_width="125dp"
    android:layout_height="35dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="120dp"
    android:layout_marginEnd="8dp"
    android:text="Amount $"
    android:textAlignment="center"
    android:textSize="26sp"
    app:layout_constraintEnd_toStartOf="@+id/userInput"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<TextView
    android:id="@+id/textView2"
    android:layout_width="127dp"
    android:layout_height="35dp"
    android:layout_marginStart="16dp"
    android:layout_marginTop="28dp"
    android:text="Custom %"
    android:textAlignment="center"
    android:textSize="26sp"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textView" />

<EditText
    android:id="@+id/userInput"
    android:layout_width="207dp"
    android:layout_height="42dp"
    android:layout_marginEnd="16dp"
    android:layout_marginTop="112dp"
    android:ems="10"
    android:hint="0.00"
    android:inputType="numberDecimal"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<SeekBar
    android:id="@+id/seekBar"
    android:layout_width="209dp"
    android:layout_height="35dp"
    android:layout_marginEnd="16dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="28dp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="1.0"
    app:layout_constraintStart_toEndOf="@+id/textView2"
    app:layout_constraintTop_toBottomOf="@+id/userInput" />

<TextView
    android:id="@+id/textView3"
    android:layout_width="123dp"
    android:layout_height="31dp"
    android:layout_marginStart="16dp"
    android:layout_marginTop="56dp"
    android:text="Tip"
    android:textAlignment="center"
    android:textSize="20sp"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textView2" />

<TextView
    android:id="@+id/textView5"
    android:layout_width="76dp"
    android:layout_height="31dp"
    android:layout_marginStart="168dp"
    android:layout_marginTop="8dp"
    android:layout_marginBottom="8dp"
    android:text="15%"
    android:textAlignment="center"
    android:textSize="18sp"
    app:layout_constraintBottom_toTopOf="@+id/textView3"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textView2"
    app:layout_constraintVertical_bias="0.666" />

<TextView
    android:id="@+id/tipDisplayPercentage"
    android:layout_width="76dp"
    android:layout_height="31dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="12dp"
    android:layout_marginEnd="8dp"
    android:textSize="18sp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.583"
    app:layout_constraintStart_toEndOf="@+id/textView5"
    app:layout_constraintTop_toBottomOf="@+id/seekBar" />

<TextView
    android:id="@+id/defaultTipAmount"
    android:layout_width="76dp"
    android:layout_height="31dp"
    android:layout_marginStart="32dp"
    android:layout_marginTop="12dp"
    android:textAlignment="center"
    android:textSize="18sp"
    app:layout_constraintStart_toEndOf="@+id/textView3"
    app:layout_constraintTop_toBottomOf="@+id/textView5" />

<TextView
    android:id="@+id/defaultTotalAmount"
    android:layout_width="73dp"
    android:layout_height="31dp"
    android:layout_marginStart="28dp"
    android:layout_marginTop="24dp"
    android:layout_marginBottom="8dp"
    android:textAlignment="center"
    android:textSize="18sp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintStart_toEndOf="@+id/textView4"
    app:layout_constraintTop_toBottomOf="@+id/defaultTipAmount"
    app:layout_constraintVertical_bias="0.0" />

<TextView
    android:id="@+id/customTotalAmount"
    android:layout_width="76dp"
    android:layout_height="31dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="24dp"
    android:layout_marginEnd="28dp"
    android:layout_marginBottom="8dp"
    android:textAlignment="center"
    android:textSize="18sp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.535"
    app:layout_constraintStart_toEndOf="@+id/defaultTotalAmount"
    app:layout_constraintTop_toBottomOf="@+id/tipDisplayAmount"
    app:layout_constraintVertical_bias="0.0" />
</android.support.constraint.ConstraintLayout>

1 个答案:

答案 0 :(得分：0)

这是推测，但是看起来当getText()返回null时，Java会在EditText本身上调用toString()。您将看到EditText实例的字符串表示形式（因为您正在使用AppCompatActivity，所以它是AppCompat）。

代替使用

userAmount = Double.parseDouble(userInputAmount.getText().toString());

您应该检查null / empty状态：

Editable text = userInputAmount.getText();
if (text == null || text.toString.length < 1) userAmount = 0; //or whatever you want as the default value
else userAmount = Double.parseDouble(text.toString());
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