使用Android进行计算

我已经获得了用户输入（EditTexts）的列表并使用它们，我想计算在TextView TotalNum中显示的总数。使用Android进行计算

logcat中显示有一些错误Expanse.java的70线，是

TotalNum.setText("£" + exTotal);

我试着拿出我认为可能造成的exTotal双图的错误但是它仍然说“不幸的是应用程序名称已停止工作'，当我输入每个EditText的所有数字后按下计算按钮。

我在做什么错？使用Unicode为英镑符号\ u00A3，而不是实际£符号

public class Expense extends Activity { 

    double exTotal, exRent, exElect, exHeat, exNet, exMobile, exOther; 
    TextView Total, TotalNum, Rent, Elect, Heat, Net, Mobile, Other; 
    EditText eRent, eElect, eHeat, eNet, eMobile, eOther; 
    String eRentS, eElectS, eHeatS, eNetS, eMobileS, eOtherS; 
    Button cal; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.expense); 

     Rent = (TextView) findViewById(R.id.tvRent); 
     Elect = (TextView) findViewById(R.id.tvElectricity); 
     Heat = (TextView) findViewById(R.id.tvHeating); 
     Net = (TextView) findViewById(R.id.tvInternet); 
     Mobile = (TextView) findViewById(R.id.tvMobile); 
     Other = (TextView) findViewById(R.id.tvOther); 
     Total = (TextView) findViewById(R.id.tvTotalExpense); 
     TotalNum = (TextView) findViewById(R.id.tvExpenseNum); 

     eRent = (EditText) findViewById(R.id.etRent); 
     eElect = (EditText) findViewById(R.id.etElectricity); 
     eHeat = (EditText) findViewById(R.id.etHeating); 
     eNet = (EditText) findViewById(R.id.etInternet); 
     eMobile = (EditText) findViewById(R.id.etMobile); 
     eOther = (EditText) findViewById(R.id.etOther); 

     cal = (Button) findViewById(R.id.bCal); 
     cal.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub    
       eRentS = eRent.getText().toString(); 
       eElectS = eElect.getText().toString(); 
       eHeatS = eHeat.getText().toString(); 
       eNetS = eNet.getText().toString(); 
       eMobileS = eMobile.getText().toString(); 
       eOtherS = eOther.getText().toString(); 

       exRent = Double.parseDouble(eRentS); 
       exElect = Double.parseDouble(eElectS); 
       exHeat = Double.parseDouble(eHeatS); 
       exNet = Double.parseDouble(eNetS); 
       exMobile = Double.parseDouble(eMobileS); 
       exOther = Double.parseDouble(eOtherS); 

       exTotal = exRent + exElect + exHeat + exNet + exMobile + exOther; 
       TotalNum.setText("£" + exTotal); 
      } 
     }); 
    } 
}

logcat的

05-30 11:45:44.694: E/AndroidRuntime(775): FATAL EXCEPTION: main 
05-30 11:45:44.694: E/AndroidRuntime(775): java.lang.NullPointerException 
05-30 11:45:44.694: E/AndroidRuntime(775): at com.studentbudget.Expense$1.onClick(Expense.java:70) 
05-30 11:45:44.694: E/AndroidRuntime(775): at android.view.View.performClick(View.java:4204) 
05-30 11:45:44.694: E/AndroidRuntime(775): at android.view.View$PerformClick.run(View.java:17355) 
05-30 11:45:44.694: E/AndroidRuntime(775): at android.os.Handler.handleCallback(Handler.java:725) 
05-30 11:45:44.694: E/AndroidRuntime(775): at android.os.Handler.dispatchMessage(Handler.java:92) 
05-30 11:45:44.694: E/AndroidRuntime(775): at android.os.Looper.loop(Looper.java:137) 
05-30 11:45:44.694: E/AndroidRuntime(775): at android.app.ActivityThread.main(ActivityThread.java:5041) 
05-30 11:45:44.694: E/AndroidRuntime(775): at java.lang.reflect.Method.invokeNative(Native Method) 
05-30 11:45:44.694: E/AndroidRuntime(775): at java.lang.reflect.Method.invoke(Method.java:511) 
05-30 11:45:44.694: E/AndroidRuntime(775): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
05-30 11:45:44.694: E/AndroidRuntime(775): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
05-30 11:45:44.694: E/AndroidRuntime(775): at dalvik.system.NativeStart.main(Native Method)

来源

2013-05-30 Mark O' Sullivan

post ur错误日志 – Senthil

请发布您的logcat日志。解决问题至关重要。 – JosephGarrone

在Eclipse中，转到窗口>显示视图> Logcat。它会显示错误日志。 –

试，Java的可能是具有识别它的一个问题。

发布另一个错误的logcat，它应该给你发生崩溃的类文件的行号。

虽然它看起来像它可能会是一个NumberFormatException异常，因为它预计的其他

来源

2013-05-30 11:08:24

我认为这不是真正的问题 –

这可能会导致一个双和可能获得一些格式的字符串因为您在编辑文本已经进入一些空间。你可以避免这个空间。

eRentS = eRent.getText().toString(); 
      eElectS = eElect.getText().toString().trim(); 
      eHeatS = eHeat.getText().toString().trim(; 
      eNetS = eNet.getText().toString().trim(; 
      eMobileS = eMobile.getText().toString().trim(; 
      eOtherS = eOther.getText().toString().trim(;

来源

2013-05-30 11:19:19

使用Android进行计算

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