Android Update Textview in Thread and Runnable

Android update TextView in Thread and Runnable

The UserInterface can only be updated by the UI Thread. You need a Handler, to post to the UI Thread:

private void startTimerThread() {
    Handler handler = new Handler();
    Runnable runnable = new Runnable() {
        private long startTime = System.currentTimeMillis();
        public void run() {
            while (gameState == GameState.Playing) {  
                try {
                    Thread.sleep(1000);
                }    
                catch (InterruptedException e) {
                    e.printStackTrace();
                }
                handler.post(new Runnable(){
                    public void run() {
                       tvTime.setText("" + ((System.currentTimeMillis() - this.startTime) / 1000));
                }
            });
            }
        }
    };
    new Thread(runnable).start();
}

Update text in a TextView from a Thread

Use the following which is the recommended way to update Widget on UiThread

game.getTextView().post(new Runnable() {
                @Override
                public void run() {
                    game.getTextView().setText(Integer.toString(score));
                }
            });

Hope this helps.

How can I update text of TextView in thread using kotlin

add UI thread surround settext or access any UI Widget inside UI thread

runOnUiThread {
   textView.setText(str)       
}

how to update textview not from main thread?

Instead of using

textView.setText("text");

use

textView.post(new Runnable(){    
    @Override
    public void run(){
        textView.setText("text");
    }    
};

This can be called from any Thread and will always execute the Runnable action on the UI Thread. Also, it does not require you to have a reference to a Context object, which saves you from making unneeded cross-references.

Update textView from thread

Any updates to the UI in an Android application must happen in the UI thread. If you spawn a thread to do work in the background you must marshal the results back to the UI thread before you touch a View. You can use the Handler class to perform the marshaling:

public class TestActivity extends Activity {
    // Handler gets created on the UI-thread
    private Handler mHandler = new Handler();

    // This gets executed in a non-UI thread:
    public void receiveMyMessage() {
        final String str = receivedAllTheMessage();
        mHandler.post(new Runnable() {
            @Override
            public void run() {
                // This gets executed on the UI thread so it can safely modify Views
                mTextView.setText(str);
            }
        });
}

The AsyncTask class simplifies a lot of the details for you and is also something you could look into. For example, I believe it provides you with a thread pool to help mitigate some of the cost associated with spawning a new thread each time you want to do background work.

Not updating TextView value with thread,Why?

Try this, I think it will solved your problem.

public class MainActivity extends AppCompatActivity {

        private Random random;
        private Handler handler;
        private TextView textView;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            textView = findViewById(R.id.tv_number);
            displayRandomNumber();
        }

        /**
         * Display random number in text view
         */
        private void displayRandomNumber()
        {
            random = new Random();
            handler = new Handler();

            handler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    int value = random.nextInt();
                    textView.setText(String.valueOf(value));
                    handler.postDelayed(this,2000);
                }
            }, 2000);
        }
    }

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