BigDecimal 导致 NumberFormatException

Question

我正在开发一款金融应用程序，我必须使用 BigDecimal 来计算 currency.Now 我正在尝试创建一个入口 activity，它正在 SharedPreferences 中搜索以前的注册，如果他们是一个它启动另一个 activity ，如果不是它启动注册 activity.The 问题是注册 activity 导致 NumberFormatException 错误，而我正在尝试构建一个新的时间对象 Profit （利润 class 包含 BigDecimal 字段）。此外，我不太确定我正在使用 SharedPreferences right.I 我不太确定我的想法和编码是否正确，因为我是 android 开发的新手，而且我我被这个问题困住了，所以我给你所有的 classes。

注册activity:

public class Registration extends Activity {

private static String enteredPassword;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    final EditText password1 = (EditText) findViewById(R.id.password1);
    final EditText password2 = (EditText) findViewById(R.id.password2);
    final EditText availability = (EditText) findViewById(R.id.availability);
    EditText profitEditText = (EditText) findViewById(R.id.profit);
    Spinner spinner = (Spinner) findViewById(R.id.period_spinner);
    Button registrationButton = (Button) findViewById(R.id.registrationButton);

    DatePicker picker = (DatePicker) findViewById(R.id.thePicker);

    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
            R.array.periods_array, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(adapter);


    final String balance =  availability.getText().toString().replace(",",".");
    String profitPeriod = ((Period) spinner.getSelectedItem()).name();
    final Profit profit = new Profit("regular_profit", profitEditText.getText().toString(),
            profitPeriod ,picker);

    registrationButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (password1.getText().toString().equals(password2.getText().toString())) {
                enteredPassword = password1.getText().toString();
                Repository.setPassword(enteredPassword, mContext);
            }
            Repository.setBalance(balance, mContext);
            Repository.setProfit(profit, mContext);
        }
    });

}

}

利润activity

public class Profit {



private Date mProfitDate;
private Date mNextProfitDate;
private BigDecimal value;

public final static String TITLE = "title";
public final static String PERIOD = "period";




Profit(String title,String value, String period, DatePicker picker) {
    this.mTitle = title;
    if(value!=null){this.value = new BigDecimal(value);}else{ this.value = new BigDecimal("0.0");};
    this.mPeriod = Period.class.cast(period);
    this.mProfitDate = Repository.getDateFromPicker(picker);
}




public long getNextProfitDate(Date profitDate, Period period){
    long unixProfitDate = profitDate.getTime() / 1000L;
    long nextProfitDate=0;
    switch (period){
        case DAILY:
            nextProfitDate = DateUtils.DAY_IN_MILLIS/1000 + unixProfitDate;
            break;
        case WEEKLY:
            nextProfitDate = DateUtils.WEEK_IN_MILLIS/1000 + unixProfitDate;
            break;
        case MONTHLY:
            Date dateNow = new Date();
            dateNow.getTime();
            nextProfitDate = Repository.monthsToSeconds(Calendar.getInstance()
                    .get(Calendar.MONTH)) + unixProfitDate;
            break;
        case YEARLY:
            nextProfitDate = DateUtils.YEAR_IN_MILLIS/1000 + unixProfitDate;
            break;
    }
    return nextProfitDate;
}

}

入口activity

public class EnterActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_enter);

    CountDownTimer timer = new CountDownTimer(3000, 100) {
        public void onTick(long millisUntilFinished) {
        }
         public void onFinish() {
            if(Repository.getPassword(mContext.getApplicationContext()).equals("No Value")){
                Intent registrationIntent = new Intent(mContext, Registration.class);
                startActivity(registrationIntent);
            }
            else{
                Intent configurationIntent = new Intent(mContext, Configuration.class);
                startActivity(configurationIntent);
            }
        }
    }.start();

}

}

存储库

public class Repository {

public static SharedPreferences sharedPreferences;


private static SharedPreferences getPrefs(Context context) {
    return context.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
}

public static String getPassword(Context context){
    return getPrefs(context).getString(PASSWORD,"No Value");
}
public Repository() {
}


public static void setPassword(String password, Context context){
    SharedPreferences.Editor editor = getPrefs(context).edit();
    editor.putString(PASSWORD, password);
    editor.commit();
}
public static void setBalance(String balance, Context context){
    SharedPreferences.Editor editor = getPrefs(context).edit();
    editor.putString(BALANCE, balance);
    editor.commit();
}

public static void setProfit(Profit profit, Context context){
    SharedPreferences.Editor editor = getPrefs(context).edit();
    editor.putString(BALANCE, profit.getValue().toString());
    editor.commit();
}

}

输出

E/AndroidRuntime: FATAL EXCEPTION: main
        E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{/.Registration}: java.lang.NumberFormatException: Bad offset/length: offset=0 len=0 in.length=0
        E/AndroidRuntime:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
        E/AndroidRuntime:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
        E/AndroidRuntime:     at android.app.ActivityThread.access0(ActivityThread.java:123)
        E/AndroidRuntime:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
        E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:99)
        E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:137)
        E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:4424)
        E/AndroidRuntime:     at java.lang.reflect.Method.invokeNative(Native Method)
        E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:511)
        E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
        E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
        E/AndroidRuntime:     at dalvik.system.NativeStart.main(Native Method)
        E/AndroidRuntime:  Caused by: java.lang.NumberFormatException: Bad offset/length: offset=0 len=0 in.length=0
        E/AndroidRuntime:     at java.math.BigDecimal.<init>(BigDecimal.java:282)
        E/AndroidRuntime:     at java.math.BigDecimal.<init>(BigDecimal.java:438)
        E/AndroidRuntime:     at .Profit.<init>(Profit.java:41)
        E/AndroidRuntime:     at .Registration.onCreate(Registration.java:57)
        E/AndroidRuntime:     at android.app.Activity.performCreate(Activity.java:4466)
        E/AndroidRuntime:     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
        E/AndroidRuntime:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
        E/AndroidRuntime:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
        E/AndroidRuntime:     at android.app.ActivityThread.access0(ActivityThread.java:123)
        E/AndroidRuntime:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
        E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:99)
        E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:137)
        E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:4424)
        E/AndroidRuntime:     at java.lang.reflect.Method.invokeNative(Native Method)
        E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:511)
        E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
        E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
        E/AndroidRuntime:     at dalvik.system.NativeStart.main(Native Method)

Answer 1

您没有正确地将字符串解析为大数。

您的 Profit 构造函数中的以下内容：

if(value!=null)
{
    this.value = new BigDecimal(value);
}
else
{ 
    this.value = new BigDecimal("0.0"); 
}

需要将字符串解析为 BigDecimal。像下面这样，其中 this.value 是 BigDecimal 类型：

this.value = (BigDecimal) decimalFormat.parse(value);

还要记住 decimalFormat.parse 可以抛出 ParseException。你需要用 try/catch 处理它或扔掉它。

Answer 2

您在您提供的代码中仅在一个地方实例化了一个 Profit：

Profit profit = new Profit("regular_profit", profitEditText.getText().toString(),
        profitPeriod, picker);

如果这导致 NumberFormatException 那么它必须来自 Profit 构造函数中的这段代码：

if(value!=null){this.value = new BigDecimal(value);}else{ this.value = new BigDecimal("0.0");};

由于 value 字符串将来自对对象的 toString() 调用，您可以相信它不是 null（无论如何，如果它是 null 那么你最终会在 new BigDecimal("0.0")，你可以自己验证它是否正常工作）。这让我们把 new BigDecimal(value) 作为罪魁祸首。 The docs for this constructor 提供参数字符串预期格式的详细信息。如果参数不符合该格式，则将抛出 NumberFormatException。

在您所描述的场景中，人们可能想象的更可能是格式错误的字符串之一，它与 Java 中的 null 不同。鉴于文本来自 UI 字段，您还必须注意有趣且难以发现的畸形，例如前导和尾随空格。

也许像这样编写构造函数的受影响部分会更好：

if (value != null) {
    value = value.trim();
    this.value = value.length() == 0 ? BigDecimal.ZERO : new BigDecimal(value);
} else {
    this.value = BigDecimal.ZERO;
}

请注意，即使进行了该更改，此构造函数仍会在出现其他类型的畸形时抛出 NumberFormatException。当你不确定数据的有效性时，你应该准备好处理这样的异常。

BigDecimal 导致 NumberFormatException

BigDecimal causes NumberFormatException

java

android

currency

bigdecimal

numberformatexception