Android crashes at .setText in Timer run
Date: 15.01.2021	Views: 1.163

Problem:

Android crashes, ifyou try to write a text in an ad Textview with .setText

Description:

With a timer, the current time should be written to an Android Activity text box for display every second

Timer timerActualDayTime = new Timer();
timerActualDayTime.schedule(new TimerTask() {
@Override
public void run() {
        String sCurrentDateTime= new SimpleDateFormat("HH:mm:ss", Locale.getDefault()).format(new Date());
        _textViewCurrentDayTime.setText(sCurrentDateTime);
        }
        }, 1000, 1000);
//textViewActualTime

At the yellow spot crashes off Android

Solution:

Timer does not have a handle on the UI

If you want to write from java code to output (UI), then you need higher rights than a timer has.

Here you have to take a handler.

Java Handler() allow access to other places such as the off-input UI

Solution: Switch to Handler()

Ok Solution works

Solution Code

TextView _textViewCurrentDayTime;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    //< init >
    _textViewCurrentDayTime = findViewById(R.id.textViewCurrentDayTime);
    refreshCurrentDateTime();
    //</ init >
}

//========< #region: Methods >========
private void refreshCurrentDateTime() {
    new Handler().postDelayed(new Runnable() {
        @Override
        public void run() {
            String sCurrentDateTime= new SimpleDateFormat("HH:mm:ss", Locale.getDefault()).format(new Date());
            _textViewCurrentDayTime.setText(sCurrentDateTime);

            //< loop: next >
            refreshCurrentDateTime();
            //< loop: next >
        }
    }, 1000);
}
//========</ #region: Methods >========