Android

Question

输入带小数点的值时，以下代码出现问题。不管我输入 56. 还是 56.3 或 56.345，它仍然会使应用程序崩溃并抛出 NumberFormatException。

这是抛出异常的代码：

private boolean isNumeric(String str) {
    try{
        Float.parseFloat(str);
    }
    catch(NumberFormatException e) {
        return false;
    }
    return true;
}

这是 logcat 的例外情况：

05-14 08:54:08.127  31142-31142/com.ritchieengineering.yellowjacket E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.ritchieengineering.yellowjacket, PID: 31142
java.lang.NumberFormatException: Invalid int: "2.5"
        at java.lang.Integer.invalidInt(Integer.java:137)
        at java.lang.Integer.parse(Integer.java:374)
        at java.lang.Integer.parseInt(Integer.java:365)
        at java.lang.Integer.parseInt(Integer.java:331)
        at java.lang.Integer.valueOf(Integer.java:489)
        at com.ritchieengineering.yellowjacket.fragment.TargetSubcoolingFragment.isValidValue(TargetSubcoolingFragment.java:164)
        at com.ritchieengineering.yellowjacket.fragment.TargetSubcoolingFragment.onOptionsItemSelected(TargetSubcoolingFragment.java:89)
        at android.app.Fragment.performOptionsItemSelected(Fragment.java:1806)
        at android.app.FragmentManagerImpl.dispatchOptionsItemSelected(FragmentManager.java:1978)
        at android.app.Activity.onMenuItemSelected(Activity.java:2711)
        at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:1094)
        at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735)
        at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:152)
        at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874)
        at com.android.internal.view.menu.ActionMenuView.invokeItem(ActionMenuView.java:645)
        at com.android.internal.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:210)
        at android.view.View.performClick(View.java:4637)
        at android.view.View$PerformClick.run(View.java:19422)
        at android.os.Handler.handleCallback(Handler.java:733)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5586)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)
        at dalvik.system.NativeStart.main(Native Method)

输入56.3或56.345时如何避免抛出这个异常？我如何检查以确保人们只输入带一位小数的值，例如 56.3？任何帮助将不胜感激。

Answer 1

听起来您的本地文化设置为使用 , 作为小数点分隔符而不是 .。您可以使用 NumberFormat 明确设置您的本地文化：

NumberFormat format = NumberFormat.getInstance(Locale.FRENCH);
Number number = format.parse("1,234");
float f = number.floatValue();

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