将输入字符串解析为整数似乎会使我的应用程序崩溃答案

【问题标题】：Parsing input strings to integers seems to crash my app将输入字符串解析为整数似乎会使我的应用程序崩溃
【发布时间】：2016-03-15 15:27:07
【问题描述】：

我开始学习 android，我的第一个练习是计算器。在做正确的计算器之前，我计划创建一个非常基本的应用程序，其中用户只需通过 EditText 输入 2 个数字，使用 Buttons 选择算术运算，并在按下“igual”按钮时在 TextView 中获取结果。

我的想法是声明 2 个字符串（sinput1 和 sinput2），它们从每个 EditText（num1 和 num2）中获取文本，然后将字符串解析为整数变量（input1 和 input2）。

在我开始对操作的运行方式进行编码之前，所有布局看起来和工作正常，但是每次我运行应用程序（使用手机或模拟器）时，当我按下 EditText 输入数字时它就会崩溃。我会把我的代码放在这里，也许我的错误在别处。

我认为改变开关在 onClick void 上的工作方式可以解决这个问题，部分原因是因为之前我有一系列的 if 并且应用程序在加载布局之前就崩溃了。但现在我被困在了这一点上。

    package com.example.caye.colores;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    Button mas;
    Button menos;
    Button por;
    Button div;
    Button igual;

    EditText num1;
    EditText num2;

    TextView letrero1;
    TextView letrero2;
    TextView resultado;

    int input1;
    int input2;
    String sinput1;
    String sinput2;
    int operacion;

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

        mas = (Button)this.findViewById(R.id.mas);
        mas.setOnClickListener(this);
        mas.setText("+");
        menos = (Button)this.findViewById(R.id.menos);
        menos.setOnClickListener(this);
        menos.setText("-");
        por = (Button)this.findViewById(R.id.por);
        por.setOnClickListener(this);
        por.setText("*");
        div = (Button)this.findViewById(R.id.div);
        div.setOnClickListener(this);
        div.setText("/");
        igual = (Button)this.findViewById(R.id.igual);
        igual.setOnClickListener(this);
        igual.setText("=");

        num1 = (EditText)this.findViewById(R.id.num1);
        num1.setOnClickListener(this);
        num2 = (EditText)this.findViewById(R.id.num2);
        num2.setOnClickListener(this);

        letrero1 = (TextView)this.findViewById(R.id.letrero1);
        letrero1.setText("Número 1");
        letrero2 = (TextView)this.findViewById(R.id.letrero2);
        letrero2.setText("Número 2");
        resultado = (TextView)this.findViewById(R.id.resultado);
        resultado.setText("");
    }

    public void onClick(View view){
        switch (view.getId()){
            case R.id.mas:
                operacion = 1;
                break;
            case R.id.menos:
                operacion = 2;
                break;
            case R.id.por:
                operacion = 3;
                break;
            case R.id.div:
                operacion = 4;
                break;
            case R.id.num1:
                sinput1 = num1.getText().toString();
                input1 = Integer.parseInt(sinput1);
                break;
            case R.id.num2:
                sinput2 = num2.getText().toString();
                input2 = Integer.parseInt(sinput2);
                break;
            case R.id.resultado:
                switch (operacion){
                    case 1:
                        resultado.setText(input1 + input2);
                        break;
                    case 2:
                        resultado.setText(input1 - input2);
                        break;
                    case 3:
                        resultado.setText(input1 * input2);
                        break;
                    case 4:
                        resultado.setText(input1 / input2);
                        break;
                    default:
                        resultado.setText("Elige una operación");
                        break;
                }
                break;
        }
    }
}

这里。

    03-15 09:41:24.234 22041-22041/? D/dalvikvm: Late-enabling CheckJNI
03-15 09:41:24.334 22041-22041/com.example.caye.colores D/HyLog: I : /data/font/config/dfactpre.dat, No such file or directory (2)
03-15 09:41:24.338 22041-22041/com.example.caye.colores D/asset: AssetManager-->addDefaultAssets CIP path not exsit!
03-15 09:41:24.502 22041-22041/com.example.caye.colores W/dalvikvm: VFY: unable to find class referenced in signature (Landroid/view/SearchEvent;)
03-15 09:41:24.502 22041-22041/com.example.caye.colores I/dalvikvm: Could not find method android.view.Window$Callback.onSearchRequested, referenced from method android.support.v7.view.WindowCallbackWrapper.onSearchRequested
03-15 09:41:24.502 22041-22041/com.example.caye.colores W/dalvikvm: VFY: unable to resolve interface method 15038: Landroid/view/Window$Callback;.onSearchRequested (Landroid/view/SearchEvent;)Z
03-15 09:41:24.502 22041-22041/com.example.caye.colores D/dalvikvm: VFY: replacing opcode 0x72 at 0x0002
03-15 09:41:24.503 22041-22041/com.example.caye.colores I/dalvikvm: Could not find method android.view.Window$Callback.onWindowStartingActionMode, referenced from method android.support.v7.view.WindowCallbackWrapper.onWindowStartingActionMode
03-15 09:41:24.503 22041-22041/com.example.caye.colores W/dalvikvm: VFY: unable to resolve interface method 15042: Landroid/view/Window$Callback;.onWindowStartingActionMode (Landroid/view/ActionMode$Callback;I)Landroid/view/ActionMode;
03-15 09:41:24.503 22041-22041/com.example.caye.colores D/dalvikvm: VFY: replacing opcode 0x72 at 0x0002
03-15 09:41:24.580 22041-22041/com.example.caye.colores I/dalvikvm: Could not find method android.content.res.TypedArray.getChangingConfigurations, referenced from method android.support.v7.widget.TintTypedArray.getChangingConfigurations
03-15 09:41:24.580 22041-22041/com.example.caye.colores W/dalvikvm: VFY: unable to resolve virtual method 396: Landroid/content/res/TypedArray;.getChangingConfigurations ()I
03-15 09:41:24.580 22041-22041/com.example.caye.colores D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002
03-15 09:41:24.581 22041-22041/com.example.caye.colores I/dalvikvm: Could not find method android.content.res.TypedArray.getType, referenced from method android.support.v7.widget.TintTypedArray.getType
03-15 09:41:24.581 22041-22041/com.example.caye.colores W/dalvikvm: VFY: unable to resolve virtual method 418: Landroid/content/res/TypedArray;.getType (I)I
03-15 09:41:24.581 22041-22041/com.example.caye.colores D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002
03-15 09:41:24.690 22041-22041/com.example.caye.colores D/BubblePopupHelper: isShowingBubblePopup : false
03-15 09:41:24.690 22041-22041/com.example.caye.colores D/BubblePopupHelper: isShowingBubblePopup : false
03-15 09:41:24.838 22041-22041/com.example.caye.colores D/GraphicBuffer: create handle(0x619ca788) (w:544, h:960, f:1)
03-15 09:41:24.844 22041-22041/com.example.caye.colores D/OpenGLRenderer: Enabling debug mode 0
03-15 09:41:24.846 22041-22041/com.example.caye.colores D/GraphicBuffer: create handle(0x61bf9318) (w:1216, h:832, f:1)
03-15 09:41:24.857 22041-22041/com.example.caye.colores D/OpenGLRenderer: setViewport 540x960 <0x619ca8c0>
03-15 09:41:24.888 22041-22041/com.example.caye.colores D/BubblePopupHelper: isShowingBubblePopup : false
03-15 09:41:24.888 22041-22041/com.example.caye.colores D/BubblePopupHelper: isShowingBubblePopup : false
03-15 09:41:24.890 22041-22041/com.example.caye.colores D/BubblePopupHelper: isShowingBubblePopup : false
03-15 09:41:24.890 22041-22041/com.example.caye.colores D/BubblePopupHelper: isShowingBubblePopup : false
03-15 09:41:24.946 22041-22041/com.example.caye.colores D/cliptray_Editor:  setInputTypeforClipTray(): 0
03-15 09:41:24.960 22041-22041/com.example.caye.colores D/BubblePopupHelper: isShowingBubblePopup : false
03-15 09:41:24.960 22041-22041/com.example.caye.colores D/BubblePopupHelper: isShowingBubblePopup : false
03-15 09:41:24.960 22041-22041/com.example.caye.colores D/BubblePopupHelper: isShowingBubblePopup : false
03-15 09:41:24.961 22041-22041/com.example.caye.colores D/BubblePopupHelper: isShowingBubblePopup : false
03-15 09:41:25.008 22041-22041/com.example.caye.colores D/cliptray_Editor:  setInputTypeforClipTray(): 0
03-15 09:41:25.446 22041-22041/com.example.caye.colores D/GraphicBuffer: create handle(0x62130980) (w:544, h:960, f:1)
03-15 09:41:25.957 22041-22041/com.example.caye.colores D/GraphicBuffer: create handle(0x6201a318) (w:544, h:960, f:1)
03-15 09:41:28.168 22041-22041/com.example.caye.colores I/ViewRootImpl: ViewRoot's Touch Event : ACTION_DOWN
03-15 09:41:28.316 22041-22041/com.example.caye.colores I/ViewRootImpl: ViewRoot's Touch Event : ACTION_UP
03-15 09:41:28.341 22041-22041/com.example.caye.colores V/Provider/Settings: get setting for user 0 by user 0 so skipping cache
03-15 09:41:28.342 22041-22041/com.example.caye.colores V/Provider/Settings: invalidate [system]: current 32 != cached 0
03-15 09:41:28.347 22041-22041/com.example.caye.colores D/AndroidRuntime: Shutting down VM
03-15 09:41:28.347 22041-22041/com.example.caye.colores W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0x4249be48)
03-15 09:41:28.355 22041-22041/com.example.caye.colores E/AndroidRuntime: FATAL EXCEPTION: main
                                                                          Process: com.example.caye.colores, PID: 22041
                                                                          java.lang.NumberFormatException: Invalid int: ""
                                                                              at java.lang.Integer.invalidInt(Integer.java:137)
                                                                              at java.lang.Integer.parseInt(Integer.java:358)
                                                                              at java.lang.Integer.parseInt(Integer.java:331)
                                                                              at com.example.caye.colores.MainActivity.onClick(MainActivity.java:81)
                                                                              at android.view.View.performClick(View.java:4461)
                                                                              at android.view.View$PerformClick.run(View.java:18523)
                                                                              at android.os.Handler.handleCallback(Handler.java:733)
                                                                              at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                              at android.os.Looper.loop(Looper.java:136)
                                                                              at android.app.ActivityThread.main(ActivityThread.java:5118)
                                                                              at java.lang.reflect.Method.invokeNative(Native Method)
                                                                              at java.lang.reflect.Method.invoke(Method.java:515)
                                                                              at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
                                                                              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605)
                                                                              at dalvik.system.NativeStart.main(Native Method)
03-15 09:41:30.416 22041-22041/com.example.caye.colores I/Process: Sending signal. PID: 22041 SIG: 9

【问题讨论】：

它崩溃了！所以发布堆栈跟踪。您还调用检查用户是否使用if(!TextUtils.isEmpty("your string") 在editText 中输入任何内容以确保安全
第二次从按钮点击上的editText获取值，因为当你点击你的editText时它会聚焦，以便你输入一些东西
也使用 try 语句来防止崩溃并能够解决确切的问题以进行故障排除。

标签： java android string parsing math

【解决方案1】：

首先，您需要提供崩溃的堆栈跟踪。

其次，您的错误极有可能来自您将Integer.parseInt(sinput1); 字符串转换为整数。

你确定那里有整数吗？您可能正在尝试将“”转换为整数。

检查EditText是否为空，是否包含数字。

if(!TextUtils.isEmpty(sinput1) && TextUtils.isDigitsOnly(sinput1)) {
    input1 = Integer.parseInt(sinput1);
}

【讨论】：

【解决方案2】：

我认为在您选择编辑文本 num1/num2 时，编辑文本内容为空。最好的方法是在按钮单击时解析编辑文本输入。还要使用 isDigitsOnly() API 检查输入是否为数字。

【讨论】：

【解决方案3】：

我们不需要为 EditTexts 使用 setOnClickListener 试试这个代码

package com.example.caye.colores;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

Button mas;
Button menos;
Button por;
Button div;
Button igual;

EditText num1;
EditText num2;

TextView letrero1;
TextView letrero2;
TextView resultado;

int input1;
int input2;
String sinput1;
String sinput2;
int operacion;

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

    mas = (Button)this.findViewById(R.id.mas);
    mas.setOnClickListener(this);
    mas.setText("+");
    menos = (Button)this.findViewById(R.id.menos);
    menos.setOnClickListener(this);
    menos.setText("-");
    por = (Button)this.findViewById(R.id.por);
    por.setOnClickListener(this);
    por.setText("*");
    div = (Button)this.findViewById(R.id.div);
    div.setOnClickListener(this);
    div.setText("/");
    igual = (Button)this.findViewById(R.id.igual);
    igual.setOnClickListener(this);
    igual.setText("=");

    num1 = (EditText)this.findViewById(R.id.num1);
    //num1.setOnClickListener(this);
    num2 = (EditText)this.findViewById(R.id.num2);
    //num2.setOnClickListener(this);

    letrero1 = (TextView)this.findViewById(R.id.letrero1);
    letrero1.setText("Número 1");
    letrero2 = (TextView)this.findViewById(R.id.letrero2);
    letrero2.setText("Número 2");
    resultado = (TextView)this.findViewById(R.id.resultado);
    resultado.setText("");
}

public void onClick(View view){
    switch (view.getId()){
        case R.id.mas:
            operacion = 1;
            break;
        case R.id.menos:
            operacion = 2;
            break;
        case R.id.por:
            operacion = 3;
            break;
        case R.id.div:
            operacion = 4;
            break;

/*
        case R.id.num1:
            sinput1 = num1.getText().toString();
            input1 = Integer.parseInt(sinput1);
            break;
        case R.id.num2:
            sinput2 = num2.getText().toString();
            input2 = Integer.parseInt(sinput2);
            break;
*/
        case R.id.resultado:


          sinput1 = num1.getText().toString();
          sinput2 = num2.getText().toString();

          if(!TextUtils.isEmpty(sinput1) && TextUtils.isDigitsOnly(sinput1)                                 
          {
          input1 = Integer.parseInt(sinput1);

          }



          if(!TextUtils.isEmpty(sinput2) && TextUtils.isDigitsOnly(sinput2)                                 
          {
          input2 = Integer.parseInt(sinput2);

          }



          if(input1 != null && input2 != null) {

          switch (operacion){
                case 1:
                    resultado.setText(input1 + input2);
                    break;
                case 2:
                    resultado.setText(input1 - input2);
                    break;
                case 3:
                    resultado.setText(input1 * input2);
                    break;
                case 4:
                    resultado.setText(input1 / input2);
                    break;
                default:
                    resultado.setText("Elige una operación");
                    break;
                } else {

                   resultado.setText("Check the inputs");

                }

            }
            break;
    }
}
}

【讨论】：