Android मध्ये layouts आणि views कसे काम करतात? · IT मुलाखत सराव

Android मध्ये layouts आणि views कसे काम करतात?

Android UIs Views (UI widgets जसे की buttons, text) आणि ViewGroups/layouts (containers जसे की LinearLayout, ConstraintLayout) यांच्या मदतीने तयार केली जातात. पारंपरिकपणे XML layouts मध्ये परिभाषित केली जातात, आधुनिक Android वेढे Jetpack Compose (declarative) वापरते. UI निर्माण करण्यासाठी view system समजणे हे मूलभूत आहे.

Views आणि ViewGroups

text

VIEW → a single UI element (TextView, Button, ImageView, EditText, etc.)
VIEWGROUP → a container that holds/arranges child views (LinearLayout, ConstraintLayout,
  FrameLayout, RecyclerView, etc.) — layouts ARE ViewGroups
→ UIs are a TREE of views inside view groups (composition).

text

LinearLayout → arrange children in a row OR column
ConstraintLayout → flexible, flat layouts via constraints between views (modern, efficient,
  the recommended layout for complex UIs)
FrameLayout → stack/overlay children
RecyclerView → efficient scrolling lists (recycles views for performance — key for lists)

xml

<!-- define the UI declaratively in an XML layout file -->
<LinearLayout android:orientation="vertical" ...>
  <TextView android:text="Hello" .../>
  <Button android:id="@+id/myButton" android:text="Click" .../>
</LinearLayout>

text

JETPACK COMPOSE → modern DECLARATIVE UI toolkit (Kotlin code, no XML):
  → describe UI as composable functions; reactive (UI updates with state)
  → Google's recommended modern approach (similar idea to Flutter/React)
→ New apps increasingly use Compose; XML layouts still common in existing apps.

Android मध्ये layouts आणि views कसे काम करतात?

Views आणि ViewGroups

Common layouts (ViewGroups)

XML layouts (traditional)

Modern: Jetpack Compose

हे का महत्वाचे आहे