安卓計算器領先peroid「。」導致崩潰

嗨，我正在製作一個簡單的歐姆定律計算器。我設置了自動計算值並在editText框更改時更新總數。當其中一個箱子空了時，我解決了一個碰撞問題。安卓計算器領先peroid「。」導致崩潰

我現在遇到的問題是每當我用小數開頭「。」我的應用程序崩潰。我能做些什麼來解決這個問題。

這是我的代碼。

package com.TWApps.SimpleOhmsLawCalc; 

import android.app.Activity; 
import android.os.Bundle; 
import android.text.Editable; 
import android.widget.*; 
import android.text.TextWatcher; 


public class voltageActivity extends Activity { 
private EditText editTextCurrent; 
private EditText editTextResistance; 
private EditText editTextVoltage; 

private double V = 0; 
private double I = 0; 
private double Re = 0; 



public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.voltagelayout); 

initcontrols(); 
} 



public void initcontrols() 
{ 
editTextVoltage = (EditText) findViewById(R.id.editTextVoltage); 
editTextCurrent = (EditText) findViewById(R.id.editTextCurrent); 
editTextResistance = (EditText) findViewById(R.id.editTextResistance); 



editTextResistance.addTextChangedListener(new TextWatcher() { 
    public void beforeTextChanged(CharSequence s, int start, int count, int after) { 
    } 

    public void onTextChanged(CharSequence s, int start, int before, int count) { 

    } 

    public void afterTextChanged(Editable s) { 
     int ReLen = editTextResistance.length(); 
     if (ReLen > 0){ 



     calculate(); 

     } 
    } 
}); 

} 


private void calculate() 
{ 

I = Double.parseDouble(editTextCurrent.getText().toString()); 
Re = Double.parseDouble(editTextResistance.getText().toString()); 


V = (I * Re); 

editTextVoltage.setText(Double.toString(V)); 


} 
}

的logcat：

02-13 22:20:41.412: I/Process(616): Sending signal. PID: 616 SIG: 9 
02-13 22:20:47.652: W/KeyCharacterMap(625): No keyboard for id 0 
02-13 22:20:47.652: W/KeyCharacterMap(625): Using default keymap: /system/usr/keychars/qwerty.kcm.bin 
02-13 22:20:49.972: D/AndroidRuntime(625): Shutting down VM 
02-13 22:20:49.972: W/dalvikvm(625): threadid=1: thread exiting with uncaught exception (group=0x40015560) 
02-13 22:20:50.002: E/AndroidRuntime(625): FATAL EXCEPTION: main 
02-13 22:20:50.002: E/AndroidRuntime(625): java.lang.NumberFormatException 
02-13 22:20:50.002: E/AndroidRuntime(625): at org.apache.harmony.luni.util.FloatingPointParser.initialParse(FloatingPointParser.java:160) 
02-13 22:20:50.002: E/AndroidRuntime(625): at org.apache.harmony.luni.util.FloatingPointParser.parseDouble(FloatingPointParser.java:281) 
02-13 22:20:50.002: E/AndroidRuntime(625): at java.lang.Double.parseDouble(Double.java:318) 
02-13 22:20:50.002: E/AndroidRuntime(625): at com.TWApps.SimpleOhmsLawCalc.voltageActivity.calculate(voltageActivity.java:70) 
02-13 22:20:50.002: E/AndroidRuntime(625): at com.TWApps.SimpleOhmsLawCalc.voltageActivity.access$1(voltageActivity.java:63) 
02-13 22:20:50.002: E/AndroidRuntime(625): at com.TWApps.SimpleOhmsLawCalc.voltageActivity$1.onTextChanged(voltageActivity.java:48) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.widget.TextView.sendOnTextChanged(TextView.java:6295) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.widget.TextView.handleTextChanged(TextView.java:6336) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:6485) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.text.SpannableStringBuilder.sendTextChange(SpannableStringBuilder.java:889) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.text.SpannableStringBuilder.change(SpannableStringBuilder.java:352) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.text.SpannableStringBuilder.change(SpannableStringBuilder.java:269) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:432) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:409) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:28) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.text.method.NumberKeyListener.onKeyDown(NumberKeyListener.java:117) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.widget.TextView.doKeyDown(TextView.java:4433) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.widget.TextView.onKeyDown(TextView.java:4267) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.view.KeyEvent.dispatch(KeyEvent.java:1256) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.view.View.dispatchKeyEvent(View.java:3855) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:789) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:789) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:789) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:789) 
02-13 22:20:50.002: E/AndroidRuntime(625): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1687) 
02-13 22:20:50.002: E/AndroidRuntime(625): at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1120) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.app.Activity.dispatchKeyEvent(Activity.java:2073) 
02-13 22:20:50.002: E/AndroidRuntime(625): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1663) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.view.ViewRoot.deliverKeyEventToViewHierarchy(ViewRoot.java:2560) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.view.ViewRoot.handleFinishedEvent(ViewRoot.java:2535) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.view.ViewRoot.handleMessage(ViewRoot.java:1867) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.os.Handler.dispatchMessage(Handler.java:99) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.os.Looper.loop(Looper.java:123) 
02-13 22:20:50.002: E/AndroidRuntime(625): at android.app.ActivityThread.main(ActivityThread.java:3683) 
02-13 22:20:50.002: E/AndroidRuntime(625): at java.lang.reflect.Method.invokeNative(Native Method) 
02-13 22:20:50.002: E/AndroidRuntime(625): at java.lang.reflect.Method.invoke(Method.java:507) 
02-13 22:20:50.002: E/AndroidRuntime(625): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
02-13 22:20:50.002: E/AndroidRuntime(625): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
02-13 22:20:50.002: E/AndroidRuntime(625): at dalvik.system.NativeStart.main(Native Method)

來源

2012-02-14 badtoy1986

崩潰？什麼是logcat輸出？ – 2012-02-14 06:05:24

在logcat中顯示的錯誤是什麼？ – 2012-02-14 06:07:25

現在你已經在日誌很明顯，對不對？計算中出現未處理的NumberFormatException。所以，處理它 - 可能是通過投訴到一個TextView中，或通過在Toast中投訴，或者通過首先處理這個特定情況（具有前導小數）並預先設置一個零。

來源

2012-02-14 06:50:16

我添加了異常，然後忽略它。它似乎工作正常。它取代了。與0.0。私人無效計算（） { \t \t \t \t 嘗試{ \t I = Double.parseDouble（editTextCurrent.getText（）的toString（））; \t Re = Double.parseDouble（editTextResistance.getText（）。toString（））; \t \t \t V =（I * Re）; （Double.toString（V））;}}; catch（NumberFormatException e）{} \t editTextVoltage.setText（Double.toString（V））; \t \t } – badtoy1986 2012-02-14 07:05:59

使用try catch塊環繞解析方法，因爲它正在生成空指針異常。

try{ 
V = Double.parseDouble(editTextVoltage.getText().toString()); 
    }catch(Exception e){ 
    V=0; 
    }

同樣遵循它所有

來源

2012-02-14 11:25:23 Rakshi

安卓計算器領先peroid「。」導致崩潰

回答

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