Question

I finally finished coding my Android calculator after so long. But the calculator won’t even start. I’d post the logcat but I don’t know how to do so. Here is my code:

///////////////////////////////////////////////////////////////

package rechee.cool;

import android.app.Activity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;




public class HelloAndroidActivity extends Activity {


    /** Called when the activity is first created. */
    public EditText display;

    double total1=0.0;
    double total2=0.0;
    char theOperator;
    public String buttonText;
    public Button ButtonAdd, ButtonEqual, ButtonMultiply, ButtonDivide, ButtonMinus;

    @Override
    public  void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        display= (EditText) findViewById(R.id.editText1);
      }

        String display1= display.getText().toString();
        double displayValue= Double.parseDouble(display1);

        public void getOperator(String btnText){
            theOperator = btnText.charAt(0);



            total1+=displayValue;
            display.setText("");
        }


            public void onClick(View v) {
                switch(v.getId()){
                    case R.id.bOne:

                        display.append("1");
                        break;
                    case R.id.bTwo:

                        display.append("2");
                        break;
                    case R.id.bThree:
                        display.append("3");
                        break;
                    case R.id.bFour:
                        display.append("4");
                        break;
                    case R.id.bFive:
                        display.append("5");
                        break;
                    case R.id.bSix:
                        display.append("6");
                        break;

                    case R.id.bSeven:
                        display.append("7");
                        break;
                    case R.id.bEight:
                        display.append("8");
                        break;
                    case R.id.bNine:
                        display.append("9");
                        break;
                    case R.id.bZero:
                        display.append("0");
                        break;
                    case R.id.bPoint:
                        display.append(".");
                        break;
                    case R.id.bClear:
                        display.setText("");
                        break;
                    case R.id.bAdd:
                        buttonText="+";
                        ButtonAdd= (Button)findViewById(R.id.bAdd);

                        ButtonAdd.setText(buttonText);


                        getOperator(buttonText);
                        break;
                    case R.id.bMinus:
                        buttonText="-";
                        ButtonMinus= (Button)findViewById(R.id.bMinus);
                        ButtonMinus.setText(buttonText);
                        getOperator(buttonText);
                        break;
                    case R.id.bMultiply:
                        buttonText="*";
                        ButtonMultiply= (Button)findViewById(R.id.bMultiply);
                        ButtonMultiply.setText(buttonText);
                        getOperator(buttonText);
                        break;
                    case R.id.bDivide:
                        buttonText="/";
                        ButtonDivide= (Button)findViewById(R.id.bDivide);
                        ButtonDivide.setText(buttonText);
                        getOperator(buttonText);
                        break;  
                    case R.id.bEqual:

                        switch (theOperator){
                        case '+':
                        total2= total1 + displayValue;
                        break;
                        case '-':
                        total2= total1 - displayValue;
                        break;
                        case '*':
                        total2= total1 * displayValue;
                        break;
                        case '/':
                        total2= total1 / displayValue;

                        break;


                        }
                        display.setText(Double.toString(total2));
                        total1=0;

                        }

                        }


}

Here’s the manifest:

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

    <uses-sdk android:minSdkVersion="10" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:name=".HelloAndroidActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

And here’s link to logcat:
http://textsnip.com/529359

Please help me out.

Answer 1

display is null so ….try this

String display1;
double displayValue;

     @Override
        public  void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            display= (EditText) findViewById(R.id.editText1);

        if(display.length()!=0){
          display1= display.getText().toString();
          displayValue= Double.parseDouble(display1);
          }

        }