Grid Layout

1. LazyVGrid

Cơ bản

let columns = [
    GridItem(.flexible()),
    GridItem(.flexible())
]

LazyVGrid(columns: columns, spacing: 16) {
    ForEach(0..<10) { index in
        RoundedRectangle(cornerRadius: 8)
            .fill(.blue)
            .frame(height: 100)
            .overlay(Text("\(index)").foregroundColor(.white))
    }
}
.padding()

GridItem Types

// Fixed width
GridItem(.fixed(100))

// Flexible (min đến max)
GridItem(.flexible(minimum: 80, maximum: 150))

// Adaptive (tự động fit nhiều items)
GridItem(.adaptive(minimum: 100))

2. Grid Examples

2 Columns Fixed

let columns = [
    GridItem(.fixed(150)),
    GridItem(.fixed(150))
]

3 Columns Flexible

let columns = Array(repeating: GridItem(.flexible()), count: 3)

Adaptive (Auto-fit)

let columns = [
    GridItem(.adaptive(minimum: 100, maximum: 150))
]

3. LazyHGrid

let rows = [
    GridItem(.fixed(60)),
    GridItem(.fixed(60))
]

ScrollView(.horizontal) {
    LazyHGrid(rows: rows, spacing: 12) {
        ForEach(0..<20) { index in
            RoundedRectangle(cornerRadius: 8)
                .fill(.orange)
                .frame(width: 80)
                .overlay(Text("\(index)").foregroundColor(.white))
        }
    }
    .padding()
}

4. Spacing và Alignment

let columns = [
    GridItem(.flexible(), spacing: 8),
    GridItem(.flexible())
]

LazyVGrid(
    columns: columns,
    alignment: .center,
    spacing: 16          // Vertical spacing
) {
    // Items
}

5. Grid (iOS 16+)

Non-lazy grid cho layout nhỏ.

Grid {
    GridRow {
        Text("Row 1, Col 1")
        Text("Row 1, Col 2")
        Text("Row 1, Col 3")
    }

    GridRow {
        Text("Row 2, Col 1")
        Text("Row 2, Col 2")
        Text("Row 2, Col 3")
    }
}

Grid với Alignment

Grid(alignment: .leading, horizontalSpacing: 12, verticalSpacing: 8) {
    GridRow {
        Text("Name:")
        Text("John Doe")
            .gridColumnAlignment(.trailing)
    }

    GridRow {
        Text("Email:")
        Text("john@example.com")
    }
}

Spanning Columns

Grid {
    GridRow {
        Text("Header")
            .gridCellColumns(2)  // Span 2 columns
    }

    GridRow {
        Text("Left")
        Text("Right")
    }
}

6. Photo Grid

struct PhotoGrid: View {
    let photos = Array(1...12)

    let columns = [
        GridItem(.flexible()),
        GridItem(.flexible()),
        GridItem(.flexible())
    ]

    var body: some View {
        ScrollView {
            LazyVGrid(columns: columns, spacing: 2) {
                ForEach(photos, id: \.self) { photo in
                    Rectangle()
                        .fill(.gray.opacity(0.3))
                        .aspectRatio(1, contentMode: .fill)
                        .overlay(
                            Image(systemName: "photo")
                                .foregroundColor(.gray)
                        )
                }
            }
        }
    }
}

7. Product Grid

struct Product: Identifiable {
    let id = UUID()
    let name: String
    let price: Double
}

struct ProductGrid: View {
    let products: [Product]

    let columns = [
        GridItem(.adaptive(minimum: 160))
    ]

    var body: some View {
        ScrollView {
            LazyVGrid(columns: columns, spacing: 16) {
                ForEach(products) { product in
                    VStack(alignment: .leading) {
                        RoundedRectangle(cornerRadius: 8)
                            .fill(.gray.opacity(0.2))
                            .aspectRatio(1, contentMode: .fill)

                        Text(product.name)
                            .font(.headline)

                        Text("$\(product.price, specifier: "%.2f")")
                            .foregroundColor(.gray)
                    }
                }
            }
            .padding()
        }
    }
}

8. Calendar Grid

struct CalendarGrid: View {
    let days = Array(1...31)
    let columns = Array(repeating: GridItem(.flexible()), count: 7)

    var body: some View {
        VStack {
            // Header
            LazyVGrid(columns: columns) {
                ForEach(["S", "M", "T", "W", "T", "F", "S"], id: \.self) { day in
                    Text(day)
                        .font(.caption)
                        .foregroundColor(.gray)
                }
            }

            // Days
            LazyVGrid(columns: columns, spacing: 8) {
                ForEach(days, id: \.self) { day in
                    Text("\(day)")
                        .frame(width: 36, height: 36)
                        .background(
                            Circle()
                                .fill(day == 15 ? .blue : .clear)
                        )
                        .foregroundColor(day == 15 ? .white : .primary)
                }
            }
        }
        .padding()
    }
}

9. Section Headers

LazyVGrid(columns: columns, pinnedViews: [.sectionHeaders]) {
    Section {
        ForEach(0..<6) { _ in
            RoundedRectangle(cornerRadius: 8)
                .fill(.blue)
                .frame(height: 100)
        }
    } header: {
        Text("Section 1")
            .font(.headline)
            .frame(maxWidth: .infinity, alignment: .leading)
            .padding()
            .background(.white)
    }

    Section {
        ForEach(0..<6) { _ in
            RoundedRectangle(cornerRadius: 8)
                .fill(.green)
                .frame(height: 100)
        }
    } header: {
        Text("Section 2")
            .font(.headline)
            .frame(maxWidth: .infinity, alignment: .leading)
            .padding()
            .background(.white)
    }
}

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📝 Tóm tắt

GridItem	Mô tả
.fixed(size)	Kích thước cố định
.flexible()	Co giãn trong khoảng
.adaptive()	Tự động fit nhiều items

Component	Mục đích
LazyVGrid	Grid dọc, lazy load
LazyHGrid	Grid ngang, lazy load
Grid	Non-lazy, iOS 16+