CS401

Android - creating UI via Code

We have seen already some examples of using xml layout files to specify GUI elements and how to attach them to variables in the code.

What if we want to completely generate the UI not in xml but in code, this shows an example how to do.

STEP 1: Create in code the GUI component

Basically, for every <GUIELEMEN> we have a class GUIELEMENT

<LinearLayout > GOES TO LinearyLayout ll = new LinearLayout(); // have series of methods for attributes ll.setOrientation(*)
<Button> GOES TO Button b = new Button();

STEP 2: Add GUI components to the Activity

From in Activity class:
- this.addContentView(ll, llParams);

An Example

UICodeActivity.java

package net.learn2develop.UICode;

import android.app.Activity;
 	        import android.os.Bundle;
 	        import android.view.ViewGroup.LayoutParams;
 	        import android.widget.Button;
 	        import android.widget.LinearLayout;
 	        import android.widget.TextView;

public class UICodeActivity extends Activity {
 	        /** Called when the activity is first created. */

 	        @Override
 	        public void onCreate(Bundle savedInstanceState) {
 	             super.onCreate(savedInstanceState);
 	             //setContentView(R.layout.main);
 	             //---param for views---
 	             LayoutParams params = 
 	             new LinearLayout.LayoutParams(
 	             LayoutParams.FILL_PARENT,
 	             LayoutParams.WRAP_CONTENT);

      //---create a layout---

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

      //---create a textview---
 	             TextView tv = new TextView(this);
 	             tv.setText("This is a TextView");
 	             tv.setLayoutParams(params);

      //---create a button---
 	             Button btn = new Button(this);
 	             btn.setText("This is a Button");
 	             btn.setLayoutParams(params);
   
     //---adds the textview---
 	             layout.addView(tv);

      //---adds the button---
 	             layout.addView(btn);

      //---create a layout param for the layout---
 	             LinearLayout.LayoutParams layoutParam = 
 	             new LinearLayout.LayoutParams(
 	             LayoutParams.FILL_PARENT,
 	             LayoutParams.WRAP_CONTENT );

   this.addContentView(layout, layoutParam);
 }
 
}