I’m trying to test if my android app works, it consists of 2 activity

Question

0

Asked: June 16, 20262026-06-16T07:57:25+00:00 2026-06-16T07:57:25+00:00

I’m trying to test if my android app works, it consists of 2 activity

0

I’m trying to test if my android app works, it consists of 2 activity screens. There are no errors in my codes but my app won’t run. It always gives me this error on the emulator “Unfortunately ‘application name’ has stopped.”

Here is my Activity code

    public class MainActivity extends Activity
{

        @Override
        public void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            View title = getWindow().findViewById(android.R.id.title);
            View titleBar = (View) title.getParent();
            titleBar.setBackgroundColor(Color.RED);
            Button next=(Button)findViewById(R.id.DGButton);
            next.setOnClickListener(new View.OnClickListener() {
                public void onClick(View view) {
                    Intent myIntent=new Intent(view.getContext(), 

    Activity2.class);
                    startActivityForResult(myIntent, 0);
                }});}

        public void calculateClickHandler(View view)
        {
            if (view.getId() == R.id.CalculateButton)
            {
                EditText ageText = (EditText)findViewById

    (R.id.AgeField);
                EditText weightText = (EditText)findViewById

    (R.id.WeightField);
                EditText ftText = (EditText)findViewById

    (R.id.HeightField);
                EditText inText = (EditText)findViewById

    (R.id.HeightField2);
                RadioGroup weightRG = (RadioGroup) findViewById

    (R.id.WeightRG);
                RadioGroup sexRG = (RadioGroup) findViewById

    (R.id.SexRG);

                TextView resultText = (TextView)findViewById

    (R.id.ResultLabel);
                TextView normalBMIText = (TextView)findViewById

    (R.id.NormalBMI);
                TextView idealKgText = (TextView)findViewById

    (R.id.IdealKgLabel);
                TextView idealLbText = (TextView)findViewById

    (R.id.IdealLbLabel);
                int age = Integer.parseInt(ageText.getText

    ().toString());
                double weight = Double.parseDouble

    (weightText.getText().toString());
                double ftheight = Double.parseDouble(ftText.getText

    ().toString());
                double inheight = Double.parseDouble(inText.getText

    ().toString());
                int checkedRadioButton1 = 

    weightRG.getCheckedRadioButtonId();
                int checkedRadioButton2 = 

    sexRG.getCheckedRadioButtonId();

                double bmiValue = calculateBMI(weight, ftheight, 

    inheight, checkedRadioButton1);
                String bmiInterpretation1 = interpretBMI1(bmiValue);
                String bmiInterpretation2 = interpretBMI2(age);
                String bmiInterpretation3 = interpretBMI3(ftheight, 

    inheight, checkedRadioButton2);
                String bmiInterpretation4 = interpretBMI4(ftheight, 

    inheight, checkedRadioButton2);

                resultText.setText(bmiValue + " - " + 

    bmiInterpretation1);
                normalBMIText.setText(""+bmiInterpretation2);
                idealKgText.setText(""+bmiInterpretation3);
                idealLbText.setText(""+bmiInterpretation4);

                Intent intent1 = new Intent(MainActivity.this, 

    Activity2.class);
                Bundle b = new Bundle();
                b.putDouble("key", bmiValue);
                intent1.putExtras(b);
                startActivity(intent1);
    }}

This is the error logcat:

12-26 02:50:45.606: E/AndroidRuntime(1776): FATAL EXCEPTION: main
12-26 02:50:45.606: E/AndroidRuntime(1776): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.bmicaldg/com.example.bmicaldg.MainActivity}: java.lang.NullPointerException
12-26 02:50:45.606: E/AndroidRuntime(1776):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at android.os.Handler.dispatchMessage(Handler.java:99)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at android.os.Looper.loop(Looper.java:137)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at android.app.ActivityThread.main(ActivityThread.java:5039)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at java.lang.reflect.Method.invokeNative(Native Method)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at java.lang.reflect.Method.invoke(Method.java:511)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at dalvik.system.NativeStart.main(Native Method)
12-26 02:50:45.606: E/AndroidRuntime(1776): Caused by: java.lang.NullPointerException
12-26 02:50:45.606: E/AndroidRuntime(1776):     at com.example.bmicaldg.MainActivity.onCreate(MainActivity.java:25)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at android.app.Activity.performCreate(Activity.java:5104)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
12-26 02:50:45.606: E/AndroidRuntime(1776):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
12-26 02:50:45.606: E/AndroidRuntime(1776):     ... 11 more

This is the debug logcat:

 12-26 03:04:06.238: I/Process(1854): Sending signal. PID: 1854 SIG: 9
    12-26 03:04:12.779: W/Trace(1876): Unexpected value from nativeGetEnabledTags: 0
    12-26 03:04:12.837: W/Trace(1876): Unexpected value from nativeGetEnabledTags: 0
    12-26 03:04:14.866: D/dalvikvm(1876): GC_CONCURRENT freed 76K, 7% free 2723K/2916K, paused 32ms+32ms, total 270ms
    12-26 03:04:15.427: D/AndroidRuntime(1876): Shutting down VM
    12-26 03:04:15.456: W/dalvikvm(1876): threadid=1: thread exiting with uncaught exception (group=0x40a70930)
    12-26 03:04:15.546: E/AndroidRuntime(1876): FATAL EXCEPTION: main
    12-26 03:04:15.546: E/AndroidRuntime(1876): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.bmicaldg/com.example.bmicaldg.MainActivity}: java.lang.NullPointerException
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at android.os.Handler.dispatchMessage(Handler.java:99)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at android.os.Looper.loop(Looper.java:137)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at android.app.ActivityThread.main(ActivityThread.java:5039)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at java.lang.reflect.Method.invokeNative(Native Method)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at java.lang.reflect.Method.invoke(Method.java:511)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at dalvik.system.NativeStart.main(Native Method)
    12-26 03:04:15.546: E/AndroidRuntime(1876): Caused by: java.lang.NullPointerException
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at com.example.bmicaldg.MainActivity.onCreate(MainActivity.java:25)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at android.app.Activity.performCreate(Activity.java:5104)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
    12-26 03:04:15.546: E/AndroidRuntime(1876):     ... 11 more
    12-26 03:04:22.547: I/Process(1876): Sending signal. PID: 1876 SIG: 9

Any help is appreciated

Report

Leave an answer
Cancel reply

You must login to add an answer.

Need An Account,

1 Answer

Editorial Team · Answer 1 · 2026-06-16T07:57:26+00:00

Change your MainActivity onCreate code as:

public class MainActivity extends Activity

{

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        View title = getWindow().findViewById(android.R.id.title);

        if (title != null) { 
             ViewParent titleBar = title.getParent(); 
           if (titleBar != null && (titleBar instanceof View)) { 
                View parentView = (View)titleBar; 
                parentView.setBackgroundColor(Color.RED); 
              } 
         } 

        // Your Code here...

Sign Up

Sign In

Forgot Password

The Archive Base Latest Questions

I’m trying to test if my android app works, it consists of 2 activity

Leave an answerCancel reply

1 Answer

Leave an answer
Cancel reply