Question

I am getting the exception of Unable to start activity ComponentInfo:java.nullpointer exception i have checked my entire code everywhere but i am not able to resolve the error

This is my code

    public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.store_denomination);
    actionbar=getSupportActionBar();
    actionbar.setDisplayShowHomeEnabled(false);
     actionbar.setDisplayShowTitleEnabled(false);
     actionbar.setDisplayShowCustomEnabled(true);
     actionbar1 = LayoutInflater.from(this).inflate(R.layout.action_custom, null);

    spin1 = (Spinner)findViewById(R.id.spin);   
    ProgressDialog progress = new ProgressDialog(this);
    progress.setMessage("Loading......");
    new MyClass(progress).execute();

    String urlvalue = ((MyApplication) getApplicationContext()).url;
    new DownloadImageTask().execute(urlvalue);




    youpaytxt = (TextView)findViewById(R.id.youpaytextview);  
    //name = (TextView)findViewById(R.id.nametextview);
    description = (TextView)findViewById(R.id.descriptiontextview);
    btncheckout = (Button)findViewById(R.id.checkoutbutton);
    edt = (EditText)findViewById(R.id.editText1);
    thumb_image = (ImageView)findViewById(R.id.imageView1);
    contshopping = (Button)findViewById(R.id.continueshoppingbutton);
    pg = (ProgressBar)findViewById(R.id.progressBar1);
    nametextview = (TextView)findViewById(R.id.nametextview);
    description = (TextView)findViewById(R.id.descriptiontextview);
    btnterms = (Button)findViewById(R.id.termsbutton);
    //termstxt=(TextView)findViewById(R.id.trmstxtview);
    //termstxt.setVisibility(termstxt.GONE);
    //termstxt.setTypeface(arial_font);

    description.setTypeface(arial_font);
    name = ((MyApplication) getApplicationContext()).nameofbrand;
    nametextview.setText(name);
    Typeface.createFromAsset(getAssets(), "fonts/arial.ttf");
    quant = String.valueOf(1);
    btn=(ImageButton)findViewById(R.id.cartbutton);
    if(!(((MyApplication)getApplicationContext()).cartproductsname).isEmpty())
    {
    btn.setOnClickListener(new OnClickListener() {          //error is coming here from logcat

        public void onClick(View v) {
            // TODO Auto-generated method stub
        Intent first=new     Intent(Detailsofproduct.this,CommentListActivity.class);   
        startActivity(first);
        }
    });
    }

This is my logcat

10-09 13:01:01.951: E/AndroidRuntime(2135): FATAL EXCEPTION: main
10-09 13:01:01.951: E/AndroidRuntime(2135): java.lang.RuntimeException: Unable to start   activity ComponentInfo{com.androidhive.xmlparsing/com.androidhive.xmlparsing.Detailsofproduct}: java.lang.NullPointerException
10-09 13:01:01.951: E/AndroidRuntime(2135):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at android.os.Looper.loop(Looper.java:123)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at android.app.ActivityThread.main(ActivityThread.java:3683)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at java.lang.reflect.Method.invokeNative(Native Method)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at java.lang.reflect.Method.invoke(Method.java:507)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at dalvik.system.NativeStart.main(Native Method)
10-09 13:01:01.951: E/AndroidRuntime(2135): Caused by: java.lang.NullPointerException
10-09 13:01:01.951: E/AndroidRuntime(2135):     at com.androidhive.xmlparsing.Detailsofproduct.onCreate(Detailsofproduct.java:209)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
10-09 13:01:01.951: E/AndroidRuntime(2135):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
10-09 13:01:01.951: E/AndroidRuntime(2135):     ... 11 more

Why am i getting the error. Any helps??

Answer 1

Change this,

  btn=(ImageButton)findViewById(R.id.cartbutton);

to

 btn=(ImageButton)actionbar1.findViewById(R.id.cartbutton);

Maybe referencing the view from where it originates should do the trick.

Because normally when you call findViewbyId(), android searches for the element only from the xml used in setContentView, since you are using a action bar view this should help.