Create a new TextView programmatically then display it below another TextView

String[] textArray={"one","two","asdasasdf asdf dsdaa"};
int length=textArray.length;
RelativeLayout layout = new RelativeLayout(this);
RelativeLayout.LayoutParams relativeParams = new RelativeLayout.LayoutParams(
		LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
for(int i=0;i<length;i++){
	TextView tv=new TextView(getApplicationContext());
	tv.setText(textArray[i]);
	relativeParams.addRule(RelativeLayout.BELOW, tv.getId());
	layout.addView(tv, relativeParams);
}

I need to do something like that.. so it would display as

one
two
asdfasdfsomething

on the screen..

If it's not important to use a RelativeLayout, you could use a LinearLayout, and do this:

LinearLayout linearLayout = new LinearLayout(this);
linearLayout.setOrientation(LinearLayout.VERTICAL);

Doing this allows you to avoid the addRule method you've tried. You can simply use addView() to add new TextViews.

Complete code:

String[] textArray = {"One", "Two", "Three", "Four"};
LinearLayout linearLayout = new LinearLayout(this);
setContentView(linearLayout);
linearLayout.setOrientation(LinearLayout.VERTICAL);        
for( int i = 0; i < textArray.length; i++ )
{
	TextView textView = new TextView(this);
	textView.setText(textArray[i]);
	linearLayout.addView(textView);
}

Try this code:

final String[] str = {"one","two","three","asdfgf"};
final RelativeLayout rl = (RelativeLayout) findViewById(R.id.rl);
final TextView[] tv = new TextView[10];
	
for (int i=0; i<str.length; i++)
{
    tv[i] = new TextView(this);	
    RelativeLayout.LayoutParams params=new RelativeLayout.LayoutParams
    	 ((int)LayoutParams.WRAP_CONTENT,(int)LayoutParams.WRAP_CONTENT);
    params.leftMargin = 50;
    params.topMargin  = i*50;
    tv[i].setText(str[i]);
    tv[i].setTextSize((float) 20);
    tv[i].setPadding(20, 50, 20, 50);
    tv[i].setLayoutParams(params);
    rl.addView(tv[i]);	
}

public View recentView;

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    
        //Create a relative layout and add a button
        relativeLayout = new RelativeLayout(this);
        btn = new Button(this);
        btn.setId((int)System.currentTimeMillis());
        recentView = btn;
        btn.setText("Click me");
        relativeLayout.addView(btn);
        
        
        setContentView(relativeLayout);
        
        btn.setOnClickListener(new View.OnClickListener() {
			
			@Overr ide
			public void onClick(View view) {

			    //Create a textView, set a random ID and position it below the most recently added view
				textView = new TextView(ActivityName.this);
				textView.setId((int)System.currentTimeMillis());
				layoutParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
				layoutParams.addRule(RelativeLayout.BELOW, recentView.getId());
				textView.setText("Time: "+System.currentTimeMillis());
				relativeLayout.addView(textView, layoutParams);
				recentView = textView;
			}
		});
    }

This can be modified to display each element of a String array in different TextViews.

You're not assigning any id to the text view, but you're using tv.getId() to pass it to the addRule method as a parameter. Try to set a unique id via tv.setId(int).

You could also use the LinearLayout with vertical orientation, that might be easier actually. I prefer LinearLayout over RelativeLayouts if not necessary otherwise.