auto_size_java.java

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

        TextView textViewLong = (TextView) findViewById(R.id.textViewLong);
        EditText editText = (EditText) findViewById(R.id.editText);

        editText.addTextChangedListener(new TextWatcher() {
            @Override
            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub
            }

            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                // TODO Auto-generated method stub
            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                textViewLong.setText(s);
            }
        });
    }