Q-3: Attempt the following (Any two) (10 Marks)

Questions

A: Describe the methods for working with Shapes in Android.
B: How can you manage Dates and Times in an Android application?
C: How can you use multiple layouts on a single screen?

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Answer A: Methods for working with Shapes in Android

Android provides several methods to create and work with shapes in applications:

1. Drawable Shapes (XML)

Creating Shape Drawables:

<!-- res/drawable/circle_shape.xml -->
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
    
    <solid android:color="#FF5722" />
    <stroke 
        android:width="2dp"
        android:color="#000000" />
    <size 
        android:width="100dp"
        android:height="100dp" />
        
</shape>

<!-- res/drawable/rectangle_shape.xml -->
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    
    <solid android:color="#2196F3" />
    <corners android:radius="10dp" />
    <stroke 
        android:width="1dp"
        android:color="#1976D2" />
    <gradient
        android:startColor="#E3F2FD"
        android:endColor="#2196F3"
        android:angle="45" />
        
</shape>

Using Shape Drawables:

<View
    android:layout_width="100dp"
    android:layout_height="100dp"
    android:background="@drawable/circle_shape" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Rounded Button"
    android:background="@drawable/rectangle_shape" />

2. Canvas and Paint (Programmatic)

public class ShapeView extends View {
    private Paint paint;
    
    public ShapeView(Context context) {
        super(context);
        init();
    }
    
    private void init() {
        paint = new Paint();
        paint.setAntiAlias(true);
    }
    
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        
        // Draw Circle
        paint.setColor(Color.RED);
        paint.setStyle(Paint.Style.FILL);
        canvas.drawCircle(100, 100, 50, paint);
        
        // Draw Rectangle
        paint.setColor(Color.BLUE);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(5);
        canvas.drawRect(50, 200, 150, 300, paint);
        
        // Draw Line
        paint.setColor(Color.GREEN);
        canvas.drawLine(0, 350, 200, 350, paint);
        
        // Draw Oval
        paint.setColor(Color.YELLOW);
        paint.setStyle(Paint.Style.FILL);
        RectF oval = new RectF(50, 400, 150, 500);
        canvas.drawOval(oval, paint);
        
        // Draw Path (Custom Shape)
        paint.setColor(Color.MAGENTA);
        Path path = new Path();
        path.moveTo(100, 550);
        path.lineTo(150, 600);
        path.lineTo(50, 600);
        path.close();
        canvas.drawPath(path, paint);
    }
}

3. Vector Drawables

<!-- res/drawable/star_vector.xml -->
<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:width="24dp"
    android:height="24dp"
    android:viewportWidth="24"
    android:viewportHeight="24">
    
    <path
        android:fillColor="#FFD700"
        android:pathData="M12,2l3.09,6.26L22,9.27l-5,4.87 1.18,6.88L12,17.77l-6.18,3.25L7,14.14 2,9.27l6.91-1.01L12,2Z" />
        
</vector>

4. Shape Types Available

1. Rectangle: android:shape="rectangle"
2. Oval: android:shape="oval"
3. Line: android:shape="line"
4. Ring: android:shape="ring"

5. Shape Attributes

<shape xmlns:android="http://schemas.android.com/apk/res/android">
    
    <!-- Solid Color -->
    <solid android:color="#color" />
    
    <!-- Gradient -->
    <gradient
        android:startColor="#color"
        android:endColor="#color"
        android:angle="45"
        android:type="linear|radial|sweep" />
    
    <!-- Stroke -->
    <stroke
        android:width="2dp"
        android:color="#color"
        android:dashWidth="4dp"
        android:dashGap="2dp" />
    
    <!-- Corners (for rectangle) -->
    <corners
        android:radius="10dp"
        android:topLeftRadius="5dp"
        android:topRightRadius="5dp"
        android:bottomLeftRadius="5dp"
        android:bottomRightRadius="5dp" />
    
    <!-- Size -->
    <size
        android:width="100dp"
        android:height="100dp" />
    
    <!-- Padding -->
    <padding
        android:left="10dp"
        android:top="10dp"
        android:right="10dp"
        android:bottom="10dp" />
        
</shape>

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Answer B: Managing Dates and Times in Android

Android provides several classes and methods to work with dates and times:

1. Date and Calendar Classes

// Using Date class
Date currentDate = new Date();
System.out.println("Current Date: " + currentDate);

// Using Calendar class
Calendar calendar = Calendar.getInstance();
int year = calendar.get(Calendar.YEAR);
int month = calendar.get(Calendar.MONTH);
int day = calendar.get(Calendar.DAY_OF_MONTH);
int hour = calendar.get(Calendar.HOUR_OF_DAY);
int minute = calendar.get(Calendar.MINUTE);

// Setting specific date
calendar.set(2024, Calendar.JANUARY, 15, 10, 30);
Date specificDate = calendar.getTime();

2. SimpleDateFormat for Formatting

// Format date to string
SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss", Locale.getDefault());
String formattedDate = formatter.format(new Date());

// Parse string to date
try {
    Date parsedDate = formatter.parse("25/12/2024 10:30:00");
} catch (ParseException e) {
    e.printStackTrace();
}

// Different format patterns
SimpleDateFormat format1 = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat format2 = new SimpleDateFormat("MMM dd, yyyy");
SimpleDateFormat format3 = new SimpleDateFormat("EEEE, MMMM dd, yyyy");

3. DatePicker and TimePicker

XML Layout:

<DatePicker
    android:id="@+id/datePicker"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:datePickerMode="spinner" />

<TimePicker
    android:id="@+id/timePicker"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:timePickerMode="spinner" />

Java Implementation:

DatePicker datePicker = findViewById(R.id.datePicker);
TimePicker timePicker = findViewById(R.id.timePicker);

// Get selected date
int year = datePicker.getYear();
int month = datePicker.getMonth();
int day = datePicker.getDayOfMonth();

// Get selected time
int hour = timePicker.getHour();
int minute = timePicker.getMinute();

// Set date programmatically
datePicker.updateDate(2024, 11, 25);

// Set time programmatically
timePicker.setHour(14);
timePicker.setMinute(30);

4. DatePickerDialog and TimePickerDialog

// DatePickerDialog
private void showDatePicker() {
    Calendar calendar = Calendar.getInstance();
    int year = calendar.get(Calendar.YEAR);
    int month = calendar.get(Calendar.MONTH);
    int day = calendar.get(Calendar.DAY_OF_MONTH);
    
    DatePickerDialog datePickerDialog = new DatePickerDialog(
        this,
        new DatePickerDialog.OnDateSetListener() {
            @Override
            public void onDateSet(DatePicker view, int selectedYear, int selectedMonth, int selectedDay) {
                String date = selectedDay + "/" + (selectedMonth + 1) + "/" + selectedYear;
                Toast.makeText(MainActivity.this, "Selected Date: " + date, Toast.LENGTH_SHORT).show();
            }
        },
        year, month, day
    );
    
    datePickerDialog.show();
}

// TimePickerDialog
private void showTimePicker() {
    Calendar calendar = Calendar.getInstance();
    int hour = calendar.get(Calendar.HOUR_OF_DAY);
    int minute = calendar.get(Calendar.MINUTE);
    
    TimePickerDialog timePickerDialog = new TimePickerDialog(
        this,
        new TimePickerDialog.OnTimeSetListener() {
            @Override
            public void onTimeSet(TimePicker view, int selectedHour, int selectedMinute) {
                String time = selectedHour + ":" + selectedMinute;
                Toast.makeText(MainActivity.this, "Selected Time: " + time, Toast.LENGTH_SHORT).show();
            }
        },
        hour, minute, true // true for 24-hour format
    );
    
    timePickerDialog.show();
}

5. Modern Date/Time API (Android API 26+)

// Using LocalDate and LocalTime (API 26+)
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    LocalDate currentDate = LocalDate.now();
    LocalTime currentTime = LocalTime.now();
    LocalDateTime currentDateTime = LocalDateTime.now();
    
    // Formatting
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd-MM-yyyy HH:mm:ss");
    String formattedDateTime = currentDateTime.format(formatter);
    
    // Parsing
    LocalDate parsedDate = LocalDate.parse("2024-12-25");
    LocalTime parsedTime = LocalTime.parse("10:30:00");
}

6. Utility Methods

public class DateTimeUtils {
    
    // Get current timestamp
    public static long getCurrentTimestamp() {
        return System.currentTimeMillis();
    }
    
    // Convert timestamp to readable date
    public static String timestampToDate(long timestamp, String pattern) {
        SimpleDateFormat sdf = new SimpleDateFormat(pattern, Locale.getDefault());
        return sdf.format(new Date(timestamp));
    }
    
    // Calculate age from birth date
    public static int calculateAge(Date birthDate) {
        Calendar birth = Calendar.getInstance();
        birth.setTime(birthDate);
        Calendar now = Calendar.getInstance();
        
        int age = now.get(Calendar.YEAR) - birth.get(Calendar.YEAR);
        if (now.get(Calendar.DAY_OF_YEAR) < birth.get(Calendar.DAY_OF_YEAR)) {
            age--;
        }
        return age;
    }
    
    // Check if date is today
    public static boolean isToday(Date date) {
        Calendar today = Calendar.getInstance();
        Calendar checkDate = Calendar.getInstance();
        checkDate.setTime(date);
        
        return today.get(Calendar.YEAR) == checkDate.get(Calendar.YEAR) &&
               today.get(Calendar.DAY_OF_YEAR) == checkDate.get(Calendar.DAY_OF_YEAR);
    }
    
    // Add days to date
    public static Date addDaysToDate(Date date, int days) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(Calendar.DAY_OF_MONTH, days);
        return calendar.getTime();
    }
}

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Answer C: Using multiple layouts on a single screen

There are several ways to use multiple layouts on a single screen in Android:

1. Nested Layouts

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    
    <!-- Header Layout -->
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:background="#2196F3">
        
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Header"
            android:layout_centerInParent="true"
            android:textColor="#FFFFFF"
            android:textSize="18sp" />
            
    </RelativeLayout>
    
    <!-- Content Layout -->
    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">
        
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal"
            android:padding="16dp">
            
            <Button
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="Button 1"
                android:layout_marginEnd="8dp" />
                
            <Button
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="Button 2"
                android:layout_marginStart="8dp" />
                
        </LinearLayout>
        
    </FrameLayout>
    
    <!-- Footer Layout -->
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:background="#4CAF50"
        android:gravity="center"
        android:orientation="horizontal">
        
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Footer"
            android:textColor="#FFFFFF" />
            
    </LinearLayout>
    
</LinearLayout>

2. Using ConstraintLayout (Recommended)

<androidx.constraintlayout.widget.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    
    <!-- Header Section -->
    <LinearLayout
        android:id="@+id/headerLayout"
        android:layout_width="0dp"
        android:layout_height="60dp"
        android:background="#2196F3"
        android:gravity="center"
        android:orientation="horizontal"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent">
        
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Header Title"
            android:textColor="#FFFFFF"
            android:textSize="18sp" />
            
    </LinearLayout>
    
    <!-- Left Panel -->
    <RelativeLayout
        android:id="@+id/leftPanel"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="#E3F2FD"
        android:layout_marginEnd="4dp"
        app:layout_constraintTop_toBottomOf="@id/headerLayout"
        app:layout_constraintBottom_toTopOf="@id/footerLayout"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toStartOf="@id/rightPanel"
        app:layout_constraintWidth_percent="0.5">
        
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Left Panel"
            android:layout_centerInParent="true" />
            
    </RelativeLayout>
    
    <!-- Right Panel -->
    <FrameLayout
        android:id="@+id/rightPanel"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="#F3E5F5"
        android:layout_marginStart="4dp"
        app:layout_constraintTop_toBottomOf="@id/headerLayout"
        app:layout_constraintBottom_toTopOf="@id/footerLayout"
        app:layout_constraintStart_toEndOf="@id/leftPanel"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintWidth_percent="0.5">
        
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Right Button"
            android:layout_gravity="center" />
            
    </FrameLayout>
    
    <!-- Footer Section -->
    <LinearLayout
        android:id="@+id/footerLayout"
        android:layout_width="0dp"
        android:layout_height="50dp"
        android:background="#4CAF50"
        android:gravity="center"
        android:orientation="horizontal"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent">
        
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Footer"
            android:textColor="#FFFFFF" />
            
    </LinearLayout>
    
</androidx.constraintlayout.widget.ConstraintLayout>

3. Using Fragments for Multiple Layouts

Main Activity Layout:

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    
    <FrameLayout
        android:id="@+id/fragment_container_1"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />
        
    <FrameLayout
        android:id="@+id/fragment_container_2"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />
        
</LinearLayout>

MainActivity.java:

public class MainActivity extends AppCompatActivity {
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        // Load different fragments
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction transaction = fragmentManager.beginTransaction();
        
        transaction.replace(R.id.fragment_container_1, new TopFragment());
        transaction.replace(R.id.fragment_container_2, new BottomFragment());
        transaction.commit();
    }
}

4. Using Include Tags

Create separate layout files:

header_layout.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="60dp"
    android:background="#2196F3"
    android:gravity="center">
    
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Header"
        android:textColor="#FFFFFF" />
        
</LinearLayout>

Main layout using include:

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    
    <!-- Include header -->
    <include layout="@layout/header_layout" />
    
    <!-- Main content area -->
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">
        
        <!-- Content here -->
        
    </RelativeLayout>
    
    <!-- Include footer -->
    <include layout="@layout/footer_layout" />
    
</LinearLayout>

5. Programmatic Layout Management

public class MainActivity extends AppCompatActivity {
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        // Create main container
        LinearLayout mainLayout = new LinearLayout(this);
        mainLayout.setOrientation(LinearLayout.VERTICAL);
        
        // Create header layout
        RelativeLayout headerLayout = new RelativeLayout(this);
        headerLayout.setBackgroundColor(Color.BLUE);
        LinearLayout.LayoutParams headerParams = new LinearLayout.LayoutParams(
            LinearLayout.LayoutParams.MATCH_PARENT, 200);
        
        TextView headerText = new TextView(this);
        headerText.setText("Header");
        headerText.setTextColor(Color.WHITE);
        headerText.setGravity(Gravity.CENTER);
        headerLayout.addView(headerText);
        
        // Create content layout
        FrameLayout contentLayout = new FrameLayout(this);
        contentLayout.setBackgroundColor(Color.LTGRAY);
        LinearLayout.LayoutParams contentParams = new LinearLayout.LayoutParams(
            LinearLayout.LayoutParams.MATCH_PARENT, 0, 1f);
        
        // Add layouts to main container
        mainLayout.addView(headerLayout, headerParams);
        mainLayout.addView(contentLayout, contentParams);
        
        setContentView(mainLayout);
    }
}

Best Practices:

1. Use ConstraintLayout for complex layouts to avoid deep nesting
2. Avoid excessive nesting of layouts for better performance
3. Use fragments for reusable UI components
4. Use include tags for common layouts across multiple screens
5. Consider ViewStub for layouts that are loaded conditionally
6. Use merge tag to eliminate redundant layout wrappers

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