Create User Interface Programmatically In Android Applications

package com.example.administrator.actionbarapp;
import android.app.ActionBar;
import android.app.Activity;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
//getSupportActionBar().setDisplayHomeAsUpEnabled(false);
super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_main);
//Create params for views---------------
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
//Create a layout---------------
LinearLayout linearLayout = new LinearLayout(this);
linearLayout.setOrientation(LinearLayout.VERTICAL);
//----Create a TextView------
TextView textView = new TextView(this);
textView.setText("This TextView is dynamically created");
textView.setLayoutParams(params);
//--Create A EditText------------------
EditText editText = new EditText(this);
editText.setLayoutParams(params);
//----Create a CheckBox-------------
CheckBox checkBox = new CheckBox(this);
checkBox.setLayoutParams(params);
//--- Create a RadioGroup---------------
RadioGroup radioGroup = new RadioGroup(this);
radioGroup.setLayoutParams(params);
//--------Create a RadioButton----------
RadioButton radioButton = new RadioButton(this);
radioButton.setLayoutParams(params);
//-----Create a Button--------
Button button = new Button(this);
button.setText("This Button is dynamically created");
button.setLayoutParams(params);
//---Add all elements to the layout
linearLayout.addView(textView);
linearLayout.addView(checkBox);
linearLayout.addView(editText);
linearLayout.addView(radioGroup);
linearLayout.addView(radioButton);
linearLayout.addView(button);
//---Create a layout param for the layout-----------------
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(ActionBar.LayoutParams.FILL_PARENT, ActionBar.LayoutParams.WRAP_CONTENT);
this.addContentView(linearLayout, layoutParams);
}
}

Explanation

Press F11 to debug the Application on the mobile device or Android emulator. The activity created looks as shown below.

If you see the code carefully, we have commented on the code

//setContentView(R.layout.activity_main);

Hence, the activity will not be loaded from the main.xml file, as it is by default in any Android Application. First, we created a LayoutParams object to specify the layout parameter, which can be used by other views.

//Create params for views---------------
LinearLayout.LayoutParams params=new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.WRAP_CONTENT);

Now, create a LinearLayout object to contain all the views in the activity.

//Create a layout---------------
LinearLayout linearLayout=new LinearLayout(this);
linearLayout.setOrientation(LinearLayout.VERTICAL);

Now, you need to create some UI elements like EditText, TextView, Button, CheckBox, RadioGroup and RadioButton etc.

//----Create a TextView------
TextView textView=new TextView(this);
textView.setText("This TextView is dynamically created");
textView.setLayoutParams(params);
//--Create A EditText------------------
EditText editText=new EditText(this);
editText.setLayoutParams(params);
//----Create a CheckBox-------------
CheckBox checkBox=new CheckBox(this);
checkBox.setLayoutParams(params);
//--- Create a RadioGroup---------------
RadioGroup radioGroup=new RadioGroup(this);
radioGroup.setLayoutParams(params);
//--------Create a RadioButton----------
RadioButton radioButton=new RadioButton(this);
radioButton.setLayoutParams(params);
//-----Create a Button--------
Button button=new Button(this);
button.setText("This Button is dynamically created");
button.setLayoutParams(params);

All the elements created above are added to the LinearLayout object.

//---Add all elements to the layout
linearLayout.addView(textView);
linearLayout.addView(checkBox);
linearLayout.addView(editText);
linearLayout.addView(radioGroup);
linearLayout.addView(radioButton);
linearLayout.addView(button);

Create a LayoutParams object to be used by the LinearLayout object.

//---Create a layout param for the layout-----------------
LinearLayout.LayoutParams layoutParams=new LinearLayout.LayoutParams(ActionBar.LayoutParams.FILL_PARENT, ActionBar.LayoutParams.WRAP_CONTENT);

Subsequently, it is added to the activity, as shown below.

this.addContentView(linearLayout,layoutParams);

Conclusion

In this article, you learned how to create UI dynamically. In the next article, I will explain about how the activities interact with the user.

Introduction

Conclusion