1. GUI Components

2. Model—View—Controller
The Model—View—Controller architecture is widely used to help deal with GUI applications.
Model
The model contains classes that represent the data used by the application. This will also include methods for manipulating and computing with that data.
View
The view is what the user sees. This is the visible interface.
Controller
The controller contains code that is executed in response to user actions and some other external events.

3. Radio Button xml file <RadioGroup android:id="@+id/radioGroup1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<RadioButton
android:layout_width="wrap_content"
android:checked="true"
android:text=“radiobutton" /> ……
</RadioGroup>

4. Radio Button
.java file
Find the RadioGroup using the method findViewById
Create a class implements the interface RadioGroup.onCheckedChangeListener
Implement onCheckedChanged method
Bind the listener class to the RadioGroup using the method setOnCheckedChangeListener
Find the checked RadioButton ID using the method radiogroupname.getCheckedRadioButtonId();

5. Check Box xml file <CheckBox android:id="@+id/checkbox1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
/>

6. Check Box .java file Find the CheckBox using the method findViewById
Create a class implements the interface CompoundButton.onCheckedChangeListener
Implement onCheckedChanged method
Bind the listener class to the CheckBox using the method setOnCheckedChangeListener
To check whether the CheckBox is checked using the method isChecked();

7. Seek Bar xml file <SeekBar android:id="@+id/seekBar1"
android:layout_width=“fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:max="44"
android:progress="29"
/>

8. Seek Bar .java file Find the SeekBar using the method findViewById
Create a class implements the interface SeekBar.onSeekBarChangeListener
Implement onProgressChanged method
Bind the listener class to the SeekBar using the method setOnSeekBarChangeListener
To check the current progress of the SeekBar using the method getProgress();