Question

当我尝试编译我的应用时，我有一个数字格式异常。以下是错误的来源：

EditText a = (EditText) findViewById(R.id.etPred_density);
        setPredDensity(Double.parseDouble(a.getText().toString()));

问题在于第二行。

以下是activity_main.xml中引用的.xml文件：

<EditText
                android:id="@+id/etPred_density"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="20dp"
                android:gravity="center_vertical|center_horizontal"
                android:hint="0.2"
                android:inputType="numberDecimal" />

这是我的清单：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="bham.eco"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="11"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ecologo"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="bham.eco.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="bham.eco.Sequence"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.Sequence" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="bham.eco.Rules"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.Rules" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

错误日志：

 FATAL EXCEPTION: main
 Process: bham.eco, PID: 2543
 java.lang.IllegalStateException: Could not execute method of the activity
    at android.view.View$1.onClick(View.java:3823)
    at android.view.View.performClick(View.java:4438)
    at android.view.View$PerformClick.run(View.java:18422)
    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:5017)
    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:779)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
    at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.reflect.InvocationTargetException
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at android.view.View$1.onClick(View.java:3818)
    ... 11 more
 Caused by: java.lang.NumberFormatException: Invalid double: ""
    at java.lang.StringToReal.invalidReal(StringToReal.java:63)
    at java.lang.StringToReal.parseDouble(StringToReal.java:248)
    at java.lang.Double.parseDouble(Double.java:295)
    at bham.eco.MainActivity.assignParams(MainActivity.java:138)
    at bham.eco.MainActivity.playit(MainActivity.java:123)
    at bham.eco.MainActivity.runit(MainActivity.java:63)
    ... 14 more

我在这里做错了什么？该异常似乎是由parseDouble（）方法引起的。

Answer 1

EditText a = (EditText) findViewById(R.id.etPred_density);
String densityValue = a.getText().toString();
Double density = null;
 try
 {
      density = Double.parseDouble(densityValue);
 }
 catch(NumberFormatException e)
 {
     //Not a number, need to handle this
 }
 // Free to carry on with density
 setPredDensity(density);

Answer 2

使用Regex检查Double格式：

EditText a = (EditText) findViewById(R.id.etPred_density);
String densityValue = a.getText().toString();

Pattern.compile("\\d+\\.\\d+");
Matcher matcher = pattern.matcher(densityValue);
boolean isDouble = matcher.matches();

if(isDouble) { 
    setPredDensity(Double.parseDouble(densityValue));
}

Answer 3

首先，我们必须在try catch块中执行此类操作。然后添加任何逻辑..

像

这样的东西

    try{
        // logic

    }catch(Exception e){

       e.printStackStrace();
   }

因此，如果像Josef所说的解析中出现任何错误数据，它可以处理..

Answer 4

请检查

 EditText a = (EditText) findViewById(R.id.etPred_density);
    if (!a.getText().toString().isEmpty()){
            setPredDensity(Double.parseDouble(a.getText().toString()));
    }

Answer 5

尝试使用a.getEditableText()代替setPredDensity（Double.parseDouble（a.getText().toString())）;

Answer 6

尝试检查是否：

其 null
其为空

真的是双重

EditText a = (EditText) findViewById(R.id.etPred_density);
if (a.getText().toString().isEmpty() || a.getText() == null) 
{
   doubleValueInvalid();
}
try
{
    setPredDensity(Double.parseDouble(a.getText().toString()));
}
catch(NumberFormatException error){  //if its not double
    doubleValueInvalid();
}

在Oracle文档中查看parseDouble抛出的内容： http://docs.oracle.com/javase/7/docs/api/java/lang/Double.html#parseDouble(java.lang.String)

用户输入中的数字格式异常

6 个答案: