CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch views

52
votes

I have an issue with the following error in Android:

CalledFromWrongThreadException;: Only the original thread that created a view hierarchy can touch its views

It appears to happen when I try to update a Textview in my Activity, the call to update the TextView is from within my Activity but I still get the above error.

I have it like this:

onCreate() -sets up the buttons and the text view.

onStateChange() - a listener for notifications about state changes, when this gets notification if changes the TextView to say some different text.

When I get notification of a new text I try to change the TextView as so:

((TextView)findViewById(R.id.title)).setText("Some Text");

But I get the above Error.

From googling it, it appears I should use a handler to change the TextView or maybe use AsyncTask?

Could anyone explain which one would be better to use and why?

EDIT: ADDED CODE SNIPPETS:

     public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);  

            setContentView(R.layout.my);

            getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.my_title);  

            ((TextView)findViewById(R.id.time)).setText("Hello Text");


            findViewById(R.id.keyboardimage).setOnClickListener(new OnClickListener() {
                public void onClick(View v) {

                    Intent dialIntent = new Intent(Intent.ACTION_DIAL, Uri.parse("tel:"));
                    startActivity(dialIntent);

                        dispatchKeyEvent(new KeyEvent(KeyEvent.ACTION_DOWN,KeyEvent.FLAG_SOFT_KEYBOARD));
                        dispatchKeyEvent(new KeyEvent(KeyEvent.ACTION_UP, KeyEvent.KEYCODE_BACK));       
                }
        });

     }

//CallBacks from running Service

private final ICallDialogActivity.Stub iCallDialogActivity = new ICallDialogActivity.Stub(){

@Override
public void onStateChanged(int callState)
                throws RemoteException {    
            switch(callState){
            case GlobalData.CALL_STATUS_IDLE:

                break;

            case GlobalData.CALL_STATUS_DISCONNECTING:
                byeSetup();
                break;
    } 

};

public void byeSetup(){

            ((TextView)findViewById(R.id.time)).setText("Bye Text");

            findViewById(R.id.keyboardimage).setOnClickListener(new OnClickListener() {
                public void onClick(View v) {
                    //Void the Button
                }});
}
6
androidhandlerandroid-asynctask
are you in a subclass? onStateChange is overridden where? – Pentium10
Hi Pentium10, it is overridden via an AIDL interface and communicates with a Service, the Service will get notified of some change and will then tell the Activity to update its TextView based on that. I have added code snippets to better demonstrate what I am attempting, The error seems to appear very randomly and appears both when the Activity is in the foreground and is not. – Donal Rafferty
possible duplicate of CalledFromWrongThreadException – jww

6 Answers

82
votes

Look like you are on the wrong thread. Try using a Handler to update the GUI on the right thread. See Handling Expensive Operations in the UI Thread example from android.com. Basically you would wrap byeSetup in a Runnable and invoke it with a Handler instance.

Handler refresh = new Handler(Looper.getMainLooper());
refresh.post(new Runnable() {
    public void run()
    {
        byeSetup();
    }
});
6
votes

when the change involves to the main thread (UiThread). Use it inside of another Thread to changes any view.

runOnUiThread(new Runnable() {
    @Override
    public void run() {

      // TODO your Code 
        et_Pass.setText("");
    }
});
3
votes

Expanding on willcodejavaforfood's answer for clarity & implementation...

I got this to work and below is how I did it. I'm running multiple processing threads in a Service so other solutions that run in Activity don't work, like runOnUiThread(new Runnable() {}...

Put this at the top of your service class so it's accessible everywhere in this class:

Handler handler;

Put this in your service class onCreate method or something that loads on Service main thread

handler= new Handler(Looper.getMainLooper());

Put this inside your additional thread to 'post back' code to get run in UI or service UI (whatevers its called):

handler.post(new Runnable() {
    public void run() {
        playNext(); //or whatever method you want to call thats currently not working
    }
});
2
votes

For others, just replace byeSetup(); with your code statements or methods. byeSetup() is a sample method. Hope it will save some of your time.

1
votes

Another approach, this time making use of android.os.Message

Have android.os.Handler defined as a field within your activity:

private final Handler myTextHandler = new Handler(new Handler.Callback() {
    @Override
    public boolean handleMessage(Message stringMessage) {
        textView.append((String) stringMessage.obj);
        return true;
    }
});

Then feed it from your other thread like this:

Message stringMessage = Message.obtain(myTextHandler);
stringMessage.obj = "Hello!";
stringMessage.sendToTarget();
0
votes

You can use view's inbuilt post method to update contents in other thread like I'm using edit text in kotlin.

address_box.post { address_box.text="my text"}