How to enable and disable toast with toggle button in Android?

Question

I have toggle button which work good for some function. But when I use for toast, toggle button is null pointer.

This is my code:

if (tgbutton.isChecked()) {
    Toast.makeText(getApplicationContext(), "MY TEXT HERE", Toast.LENGTH_LONG).show();
    }

App is working well when use toast with no toggle button, but app is crashed when I used toast with toggle button.

How to use toast with toggle button?

Thanks

EDIT:

This is from logcat:

05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): 05-20 21:59:07.568: E/AndroidRuntime(26777): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mygames.testpackage2/com.testpackage.challenge.CH__QuestionActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.widget.ToggleButton.isChecked()' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2316) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2376) at android.app.ActivityThread.access$800(ActivityThread.java:147) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1281) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5253) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.widget.ToggleButton.isChecked()' on a null object reference at com.testpackage.challenge.CH__QuestionActivity.displayQuestion(CH__QuestionActivity.java:613) at com.testpackage.challenge.CH__QuestionActivity.displayNextQuestion(CH__QuestionActivity.java:554) at com.testpackage.challenge.CH__QuestionActivity.onCreate(CH__QuestionActivity.java:218) at android.app.Activity.performCreate(Activity.java:5975) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2269) ... 10 more

post the stack trace of the exception that caused the crash – Veneet Reddy May 20 '17 at 14:57 — Veneet Reddy, May 20 '17 at 14:57

score 0 · Answer 1 · answered May 20 '17 at 14:46

0

I think problem is about Context that you pass to toast.

if (tgbutton.isChecked()) {
    Toast.makeText(this, "MY TEXT HERE", Toast.LENGTH_LONG).show();
}

or if you are in fragment,

if (tgbutton.isChecked()) {
    Toast.makeText(getContext(), "MY TEXT HERE", Toast.LENGTH_LONG).show();
}

Make sure you call this from UI thread.

Good luck there

Emre

answered May 20 '17 at 14:46

Emre Aktürk

3,306
2
18
30

I will check. Thanks @emre-aktürk – Bonnie7 May 20 '17 at 14:48
If not, can you also provide crash log please? – Emre Aktürk May 20 '17 at 14:49
05-20 21:53:59.025: E/AndroidRuntime(26122): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.widget.ToggleButton.isChecked()' on a null object reference – Bonnie7 May 20 '17 at 14:54
Your both suggestion is not working.Do you have any suggestion? Thanks – Bonnie7 May 20 '17 at 14:55

score 0 · Answer 2 · answered May 20 '17 at 15:08

0

tgButton is not initialized. Ensure it is initialized by:

ToggleButton tgButton = (ToggleButton) findViewById(R.id.your_tg_button_id);

answered May 20 '17 at 15:08

Veneet Reddy

2,707
1
24
40

Toggle button is work fine with another function, eg. sound on/off. I was initialized like this: tgbutton = (ToggleButton) findViewById(R.id.toggleButton2); – Bonnie7 May 20 '17 at 15:13

score 0 · Accepted Answer · answered May 20 '17 at 15:15

The stack trace show that your tgbutton is null.

java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.widget.ToggleButton.isChecked()' on a null object reference 05-20 21:59:07.568: E/AndroidRuntime(26777)

There are 2 things you should to correct:

1) Make sure to bind your view.

ToggleButton tgButton = (ToggleButton) findViewById(R.id.your_tg_button_id);

2) Make sure to check null before use:

if (null != tgbutton && tgbutton.isChecked()) {
    Toast.makeText(getApplicationContext(), "MY TEXT HERE", Toast.LENGTH_LONG).show();
}

score 0 · Answer 4 · edited May 20 '17 at 17:01

Solution:-

ToggleButton tb;

tb = (ToggleButton)findViewById(R.id.toggle_button_id);

if(tb.equals("ON") {

    Toast.makeText(getApplicationContext(), "Message", Toast.LENGTH_LONG).show();
} else {

    Toast.makeText(getApplicationContext(), "Else Part", Toast.LENGTH_LONG).show();
}

Cheers!!

P.S : I think, it is not a good practice to use isChecked() for ToggleButton.

From the report of logcat you may found that ToggleButton is having only boolean

of options (On or Off). So you need not to verify with isChecked() function.

How to enable and disable toast with toggle button in Android?

4 Answers4