android trying to add a TextView dynamically : I am trying to add a TextView widget dynamically in the code but it keeps crashing in the setText() line:

    TextView tv = new TextView(MainActivity.this);
    tv.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    tv.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    tv.setText("YOU: " + ET_message.getText().toString()); //this line crashes
    ll = (LinearLayout) findViewById(R.id.LL);
    ll.addView(tv);
does anybody know why? It's supposed to be the easiest line here.