Unable to add window -- token null is not valid; is your activity running? in AutoCompletetextView

Question

I have open the camera and click the camera picture go for next activity that time should be my application was crashed .I don't know what is the error.please let me know this error.Am getting this error was autocompletetextviewChnged error why.

    autoexheader.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

        }

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
            if (charSequence.length() == 0) {
                autoexheader.showDropDown();
            }


        }

        @Override
        public void afterTextChanged(Editable editable) {
            if (editable.length() == 0) {
                autoexheader.showDropDown();
            }
        }
    });

Below error

 android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running?
    at android.view.ViewRootImpl.setView(ViewRootImpl.java:965)
    at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:387)
    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:96)
    at android.widget.PopupWindow.originalInvokePopup(PopupWindow.java:1590)
    at android.widget.PopupWindow.invokePopup(PopupWindow.java:1575)
    at android.widget.PopupWindow.showAsDropDown(PopupWindow.java:1426)
    at android.widget.ListPopupWindow.originalShow(ListPopupWindow.java:734)
    at android.widget.ListPopupWindow.show(ListPopupWindow.java:645)
    at android.widget.AutoCompleteTextView.showDropDown(AutoCompleteTextView.java:1316)
    at com.ppms.expensemanger.view.Expense$2.onTextChanged(Expense.java:174)
    at android.widget.TextView.sendOnTextChanged(TextView.java:10572)
    at android.widget.TextView.setText(TextView.java:6299)
    at android.widget.TextView.setText(TextView.java:6124)
    at android.widget.EditText.setText(EditText.java:122)
    at android.widget.TextView.setText(TextView.java:6076)
    at android.widget.TextView.onRestoreInstanceState(TextView.java:5943)
    at android.view.View.dispatchRestoreInstanceState(View.java:19935)
    at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:3892)
    at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:3892)
    at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:3892)
    at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:3892)
    at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:3892)
    at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:3892)
    at android.view.View.restoreHierarchyState(View.java:19913)
    at com.android.internal.policy.PhoneWindow.restoreHierarchyState(PhoneWindow.java:2162)
    at android.app.Activity.onRestoreInstanceState(Activity.java:1602)
    at android.app.Activity.performRestoreInstanceState(Activity.java:1557)
    at android.app.Instrumentation.callActivityOnRestoreInstanceState(Instrumentation.java:1354)
    at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3351)
    at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:221)
    at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:201)
    at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:173)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2047)
    at android.os.Handler.dispatchMessage(Handler.java:107)
    at android.os.Looper.loop(Looper.java:224)
    at android.app.ActivityThread.main(ActivityThread.java:7592)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)

Answer 1

There is some dialog or other kind of window being added before your activity is shown to user , thus there is no token available to added a new window ,try using post on your view it might help you to solve your error.

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    
    autoexheader.post(new Runnable() {
        @Override
        public void run() {

            autoexheader.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

            }

            @Override
            public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
                if (charSequence.length() == 0) {
                    autoexheader.showDropDown();
                }


            }

            @Override
            public void afterTextChanged(Editable editable) {
                if (editable.length() == 0) {
                    autoexheader.showDropDown();
                }
            }
        });

        }
    });