Application has stopped working in android

Question

This is my fourthpage class in my application. I am getting the error

unfortunately application has stopped working

I have no idea why am I getting this.

package student.a.a;

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

import java.text.DecimalFormat;

public class fourthpage extends Activity {
    EditText txtb1, txtb2, txtb3, txtb4, txtb5;
    Button btnper;
    TextView lblgrade, lblper;

    DecimalFormat df = new DecimalFormat("##.##");

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fourthxml);

        // text boxes
        txtb1 = (EditText) findViewById(R.id.txtb1);
        txtb2 = (EditText) findViewById(R.id.txtb2);
        txtb3 = (EditText) findViewById(R.id.txtb3);
        txtb4 = (EditText) findViewById(R.id.txtb4);
        txtb5 = (EditText) findViewById(R.id.txtb5);

        // buttons
        btnper = (Button) findViewById(R.id.btnper);

        // labels/text view
        lblgrade = (TextView) findViewById(R.id.lblgrade);
        lblper = (TextView) findViewById(R.id.lblgrade);
    }

    String tb1 = txtb1.getText().toString();
    String tb2 = txtb2.getText().toString();
    String tb3 = txtb3.getText().toString();
    String tb4 = txtb4.getText().toString();
    String tb5 = txtb5.getText().toString();

    double txb1 = Double.parseDouble(tb1);
    double txb2 = Double.parseDouble(tb2);
    double txb3 = Double.parseDouble(tb3);
    double txb4 = Double.parseDouble(tb4);
    double txb5 = Double.parseDouble(tb5);

    double sum = 0;
    double total = 0;

    public void onClickper(View v) {
        sum = txb1 + txb2 + txb3 + txb4 + txb5;
        total = (sum / 500) * 100;
        String tot = df.format(total);
        lblper.setText(tot);

        if (total <= 100) {
            lblgrade.setText("Congratulations !! , Grade 'A+' ");
        } else if (total <= 80) {
            lblgrade.setText("Congratulations !! , Grade 'A'");
        } else if (total <= 70) {
            lblgrade.setText("Grade 'B'");
        } else if (total <= 60) {
            lblgrade.setText("Grade 'C'");
        } else
            lblgrade.setText("Failed");
    }
}

This is the xml code of fourthpage. It contains 5 text boxes, a button and two textviews:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TableLayout
        android:id="@+id/tableLayout1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <TableRow
            android:id="@+id/tableRow1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <GridLayout
                android:id="@+id/gridLayout1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/textView1"
                    android:layout_gravity="left"
                    android:text="Calculate your marks"
                    android:textAppearance="?android:attr/textAppearanceMedium" />

            </GridLayout>

        </TableRow>

        <TableRow
            android:id="@+id/tableRow7"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <GridLayout
                android:id="@+id/gridLayout3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <Space android:layout_gravity="fill_horizontal" />

            </GridLayout>

        </TableRow>

        <TableRow
            android:id="@+id/tableRow2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <GridLayout
                android:id="@+id/gridLayout2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/textView2"
                    android:layout_gravity="left"
                    android:text="Subject 1"
                    android:textAppearance="?android:attr/textAppearanceMedium" />

                <EditText
                    android:id="@+id/txtb1"
                    android:layout_width="162dp"
                    android:layout_gravity="fill_horizontal" >

                    <requestFocus />
                </EditText>

            </GridLayout>

        </TableRow>

        <TableRow
            android:id="@+id/tableRow3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <GridLayout
                android:id="@+id/GridLayout01"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/TextView01"
                    android:layout_gravity="left"
                    android:text="Subject 2"
                    android:textAppearance="?android:attr/textAppearanceMedium" />

                <EditText
                    android:id="@+id/txtb2"
                    android:layout_gravity="fill_horizontal" />

            </GridLayout>

        </TableRow>

        <TableRow
            android:id="@+id/tableRow4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <GridLayout
                android:id="@+id/GridLayout02"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/TextView02"
                    android:layout_gravity="left"
                    android:text="Subject 3"
                    android:textAppearance="?android:attr/textAppearanceMedium" />

                <EditText
                    android:id="@+id/txtb3"
                    android:layout_gravity="fill_horizontal" />

            </GridLayout>

        </TableRow>

        <TableRow
            android:id="@+id/tableRow5"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <GridLayout
                android:id="@+id/GridLayout03"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/TextView03"
                    android:layout_gravity="left"
                    android:text="Subject 4"
                    android:textAppearance="?android:attr/textAppearanceMedium" />

                <EditText
                    android:id="@+id/txtb4"
                    android:layout_gravity="fill_horizontal" />

            </GridLayout>

        </TableRow>

        <TableRow
            android:id="@+id/tableRow6"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <GridLayout
                android:id="@+id/GridLayout04"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/TextView04"
                    android:layout_gravity="left"
                    android:text="Subject 5"
                    android:textAppearance="?android:attr/textAppearanceMedium" />

                <EditText
                    android:id="@+id/txtb5"
                    android:layout_gravity="fill_horizontal" />

            </GridLayout>

        </TableRow>

        <TableRow
            android:id="@+id/tableRow8"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <GridLayout
                android:id="@+id/gridLayout4"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >



                <Button
                    android:id="@+id/btnper"
                    android:layout_gravity="left"
                    android:text="Button" android:onClick="onClickper"/>

                <Button
                    android:id="@+id/btngrade"
                    android:layout_gravity="left"
                    android:text="Button" />

            </GridLayout>

        </TableRow>

        <TableRow
            android:id="@+id/tableRow9"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <GridLayout
                android:id="@+id/gridLayout5"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/textView3"
                    android:layout_gravity="left"
                    android:text="percentage is  "
                    android:textAppearance="?android:attr/textAppearanceSmall" />

                <TextView
                    android:id="@+id/lblper"
                    android:layout_gravity="left"
                    android:text="Large Text"
                    android:textAppearance="?android:attr/textAppearanceLarge" />

            </GridLayout>

        </TableRow>

        <TableRow
            android:id="@+id/tableRow10"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <GridLayout
                android:id="@+id/gridLayout6"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/textView5"
                    android:layout_gravity="left"
                    android:text=" Grade is           "
                    android:textAppearance="?android:attr/textAppearanceSmall" />

                <TextView
                    android:id="@+id/lblgrade"
                    android:layout_gravity="left"
                    android:text="Large Text"
                    android:textAppearance="?android:attr/textAppearanceLarge" />

            </GridLayout>

        </TableRow>

    </TableLayout>

</LinearLayout>

Here is androidmanifest.xml:

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

    <uses-sdk android:minSdkVersion="14" />

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

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity
            android:label="@string/app_name"
            android:name=".secondpage" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity
            android:label="@string/app_name"
            android:name=".thirdpage" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity
            android:label="@string/app_name"
            android:name=".fourthpage" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />

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

Here is my logcat:

08-09 16:32:00.970: W/dalvikvm(892): threadid=1: thread exiting with uncaught exception (group=0x409961f8)
08-09 16:32:00.980: E/AndroidRuntime(892): FATAL EXCEPTION: main
08-09 16:32:00.980: E/AndroidRuntime(892): java.lang.RuntimeException: Unable to start activity ComponentInfo{student.a.a/student.a.a.fourthpage}: java.lang.NumberFormatException: Invalid double: ""
08-09 16:32:00.980: E/AndroidRuntime(892):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1955)
08-09 16:32:00.980: E/AndroidRuntime(892):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
08-09 16:32:00.980: E/AndroidRuntime(892):  at android.app.ActivityThread.access$600(ActivityThread.java:122)
08-09 16:32:00.980: E/AndroidRuntime(892):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
08-09 16:32:00.980: E/AndroidRuntime(892):  at android.os.Handler.dispatchMessage(Handler.java:99)
08-09 16:32:00.980: E/AndroidRuntime(892):  at android.os.Looper.loop(Looper.java:137)
08-09 16:32:00.980: E/AndroidRuntime(892):  at android.app.ActivityThread.main(ActivityThread.java:4340)
08-09 16:32:00.980: E/AndroidRuntime(892):  at java.lang.reflect.Method.invokeNative(Native Method)
08-09 16:32:00.980: E/AndroidRuntime(892):  at java.lang.reflect.Method.invoke(Method.java:511)
08-09 16:32:00.980: E/AndroidRuntime(892):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
08-09 16:32:00.980: E/AndroidRuntime(892):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
08-09 16:32:00.980: E/AndroidRuntime(892):  at dalvik.system.NativeStart.main(Native Method)
08-09 16:32:00.980: E/AndroidRuntime(892): Caused by: java.lang.NumberFormatException: Invalid double: ""
08-09 16:32:00.980: E/AndroidRuntime(892):  at java.lang.StringToReal.invalidReal(StringToReal.java:63)
08-09 16:32:00.980: E/AndroidRuntime(892):  at java.lang.StringToReal.parseDouble(StringToReal.java:248)
08-09 16:32:00.980: E/AndroidRuntime(892):  at java.lang.Double.parseDouble(Double.java:295)
08-09 16:32:00.980: E/AndroidRuntime(892):  at student.a.a.fourthpage.onCreate(fourthpage.java:61)
08-09 16:32:00.980: E/AndroidRuntime(892):  at android.app.Activity.performCreate(Activity.java:4465)
08-09 16:32:00.980: E/AndroidRuntime(892):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
08-09 16:32:00.980: E/AndroidRuntime(892):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1919)
08-09 16:32:00.980: E/AndroidRuntime(892):  ... 11 more

Please add logcat output including a *Stacktrace* of the Exception. — Sascha Kolberg, Aug 09 '15 at 10:50
`Caused by: java.lang.NumberFormatException: Invalid double: "" at student.a.a.fourthpage.onCreate(fourthpage.java:61)` Sounds pretty straightforward to me. Tells you the problem, the file, the method, even the line number. So, which part of this doesn't make sense to you? — takendarkk, Aug 09 '15 at 11:36
Code like `String tb1 = txtb1.getText().toString();` has to be in a method. You can't call methods from a class body like that. — takendarkk, Aug 09 '15 at 11:37
http://stackoverflow.com/questions/3988788/what-is-a-stack-trace-and-how-can-i-use-it-to-debug-my-application-errors — nhaarman, Aug 09 '15 at 11:46
I am a newbee to android that is why can't find it easy to read the logcat and find error — Saeed ur Rehman, Aug 09 '15 at 12:08

Dalija Prasnikar · Accepted Answer · 2015-08-09T11:48:35.000

Just because you have put your variable declarations after onCreate that does not mean this code will execute after onCreate. All your String members will be initialized before onCreate is called and before EditText members are initialized. Same goes for your double members.

String tb1 = txtb1.getText().toString();
String tb2 = txtb2.getText().toString();
String tb3 = txtb3.getText().toString();
String tb4 = txtb4.getText().toString();
String tb5 = txtb5.getText().toString();

double txb1= Double.parseDouble(tb1);
double txb2= Double.parseDouble(tb2);
double txb3= Double.parseDouble(tb3);
double txb4= Double.parseDouble(tb4);
double txb5= Double.parseDouble(tb5);

You have to move above initialization into onCreate and declare String and double members separately.

...
String tb1, tb2, tb3, tb4, tb5;    
double txb1, txb2, txb, txb4, txb5;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.fourthxml);

    //text boxes
    txtb1=(EditText)findViewById(R.id.txtb1);
    txtb2=(EditText)findViewById(R.id.txtb2);
    txtb3=(EditText)findViewById(R.id.txtb3);
    txtb4=(EditText)findViewById(R.id.txtb4);
    txtb5=(EditText)findViewById(R.id.txtb5);

    //buttons
    btnper=(Button)findViewById(R.id.btnper);

    //labels/text view
    lblgrade=(TextView)findViewById(R.id.lblgrade);
    lblper=(TextView)findViewById(R.id.lblgrade);

    tb1 = txtb1.getText().toString();
    tb2 = txtb2.getText().toString();
    tb3 = txtb3.getText().toString();
    tb4 = txtb4.getText().toString();
    tb5 = txtb5.getText().toString();

    txb1= Double.parseDouble(tb1);
    txb2= Double.parseDouble(tb2);
    txb3= Double.parseDouble(tb3);
    txb4= Double.parseDouble(tb4);
    txb5= Double.parseDouble(tb5);
}

You are getting NumberFormatException because you are parsing empty string. You can use following method to safely parse double or set its value to some default if string does not contain valid double value.

public double getDoubleOrDefault(String value, double defValue)
{
    try
    {
        return Double.parseDouble(value);
    }
    catch (Exception ex)
    {
        return defValue;
    }
}

txb1 = getDoubleOrDefault(tb1, 0.0);

Double.parseDouble documentation

thanks for your answer, but I am still getting the aplication stopped error. here is my logCat — Saeed ur Rehman, Aug 09 '15 at 11:07

Application has stopped working in android

1 Answers1