Question

我制作了一个计算器的应用程序，用户将在其中提供数字，点击按钮即可获得输出。

当我在模拟器中运行它时，它显示“Unfortunately, <app> has stopped”。

我的Logcat是：

01-15 05:56:24.200: E/AndroidRuntime(874): FATAL EXCEPTION: main
01-15 05:56:24.200: E/AndroidRuntime(874): Process: com1.example.calculator, PID: 874
01-15 05:56:24.200: E/AndroidRuntime(874): java.lang.IllegalStateException: Could not 
execute method of the activity
01-15 05:56:24.200: E/AndroidRuntime(874):  at android.view.View$1.onClick(View.java:3814)
01-15 05:56:24.200: E/AndroidRuntime(874):  at android.view.View.performClick(View.java:4424)
01-15 05:56:24.200: E/AndroidRuntime(874):  at android.view.View$PerformClick.run(View.java:18383)
01-15 05:56:24.200: E/AndroidRuntime(874):  at android.os.Handler.handleCallback(Handler.java:733)
01-15 05:56:24.200: E/AndroidRuntime(874):  at android.os.Handler.dispatchMessage(Handler.java:95)
01-15 05:56:24.200: E/AndroidRuntime(874):  at android.os.Looper.loop(Looper.java:137)
01-15 05:56:24.200: E/AndroidRuntime(874):  at android.app.ActivityThread.main(ActivityThread.java:4998)
01-15 05:56:24.200: E/AndroidRuntime(874):  at java.lang.reflect.Method.invokeNative(Native Method)
01-15 05:56:24.200: E/AndroidRuntime(874):  at java.lang.reflect.Method.invoke(Method.java:515)
01-15 05:56:24.200: E/AndroidRuntime(874):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
01-15 05:56:24.200: E/AndroidRuntime(874):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
01-15 05:56:24.200: E/AndroidRuntime(874):  at dalvik.system.NativeStart.main(Native Method)
01-15 05:56:24.200: E/AndroidRuntime(874): Caused by: java.lang.reflect.InvocationTargetException
01-15 05:56:24.200: E/AndroidRuntime(874):  at java.lang.reflect.Method.invokeNative(Native Method)
01-15 05:56:24.200: E/AndroidRuntime(874):  at java.lang.reflect.Method.invoke(Method.java:515)
01-15 05:56:24.200: E/AndroidRuntime(874):  at android.view.View$1.onClick(View.java:3809)
01-15 05:56:24.200: E/AndroidRuntime(874):  ... 11 more
01-15 05:56:24.200: E/AndroidRuntime(874): Caused by: java.lang.NumberFormatException: Invalid int: ""
01-15 05:56:24.200: E/AndroidRuntime(874):  at java.lang.Integer.invalidInt(Integer.java:137)
01-15 05:56:24.200: E/AndroidRuntime(874):  at java.lang.Integer.parseInt(Integer.java:358)
01-15 05:56:24.200: E/AndroidRuntime(874):  at java.lang.Integer.parseInt(Integer.java:331)
01-15 05:56:24.200: E/AndroidRuntime(874):  at com1.example.calculator.Cal.Add(Cal.java:26)
01-15 05:56:24.200: E/AndroidRuntime(874):  ... 14 more

我的代码：

package com1.example.calculator;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;


public class Cal extends Activity {
EditText e1,e2,e3;
int a,b,c;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_cal);
}
public void Add(View v)
{
    e1=(EditText)findViewById(R.id.editText1);
    e2=(EditText)findViewById(R.id.editText2);
    e1=(EditText)findViewById(R.id.editText3);
    String s1=e1.getText().toString();
    String s2=e2.getText().toString();
    a=Integer.parseInt(s1);
    b=Integer.parseInt(s2);
    c=a+b;
    String s3=Integer.toString(c);
    e3.setText(s3);
}
public void sub(View v)
{
    e1=(EditText)findViewById(R.id.editText1);
    e2=(EditText)findViewById(R.id.editText2);
    e1=(EditText)findViewById(R.id.editText3);
    String s1=e1.getText().toString();
    String s2=e2.getText().toString();
    a=Integer.parseInt(s1);
    b=Integer.parseInt(s2);
    c=a-b;
    String s3=Integer.toString(c);
    e3.setText(s3);
}
public void Mul (View v)
{
    e1=(EditText)findViewById(R.id.editText1);
    e2=(EditText)findViewById(R.id.editText2);
    e1=(EditText)findViewById(R.id.editText3);
    String s1=e1.getText().toString();
    String s2=e2.getText().toString();
    a=Integer.parseInt(s1);
    b=Integer.parseInt(s2);
    c=a*b;
    String s3=Integer.toString(c);
    e3.setText(s3);
}
public void Div (View v)
{
    e1=(EditText)findViewById(R.id.editText1);
    e2=(EditText)findViewById(R.id.editText2);
    e1=(EditText)findViewById(R.id.editText3);
    String s1=e1.getText().toString();
    String s2=e2.getText().toString();
    a=Integer.parseInt(s1);
    b=Integer.parseInt(s2);
    c=a/b;
    String s3=Integer.toString(c);
    e3.setText(s3);
}
public void Percentage(View v)
{
    e1=(EditText)findViewById(R.id.editText1);
    e2=(EditText)findViewById(R.id.editText2);
    e1=(EditText)findViewById(R.id.editText3);
    String s1=e1.getText().toString();
    String s2=e2.getText().toString();
    a=Integer.parseInt(s1);
    b=Integer.parseInt(s2);
    c=(a*b)/100;
    String s3=Integer.toString(c);
    e3.setText(s3);
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.cal, menu);
    return true;
}``

}

Xml文件：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".Cal" >

<EditText
    android:id="@+id/editText1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:layout_marginLeft="21dp"
    android:layout_marginTop="27dp"
    android:ems="10"
    android:inputType="number"/>
<requestFocus/>
<EditText
    android:id="@+id/editText2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/editText1"
    android:layout_below="@+id/editText1"
    android:layout_marginTop="20dp"
    android:ems="10"
    android:inputType="number" />

<Button
    android:id="@+id/button2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button3"
    android:layout_toRightOf="@+id/button3"
    android:onClick="Sub"
    android:text="Subtraction" />

Answer 1

当您尝试解析为空的String时，会发生此错误onClick方法。你能用代码来识别确切的行。

只需验证您的文字是否为空EditText.getText().isEmpty()，即使没有此验证，您也可以获得零除法异常。

Android AVD“不幸的是，<app>已停止。”执行计算器应用程序时</app>

1 个答案: