Java 16 Mobile phones and Android (Poul Klausen)（Z-Library）

【One-Line Pitch】 A hands-on Android development workbook that teaches mobile app construction through complete, tested Java examples—from layouts and widgets to SQLite, threads, and services. Best suited for developers who already know Java and want practical, example-driven Android skills rather than theory. 【Book Arc】 - **Opening (~0%–10%)**: Orients you to the toolchain (NetBeans, Android Studio, MySQL, GlassFish) and the book's philosophy—software development through worked examples, not reference-manual completeness. - **Early (~10%–32%)**: Builds UI fundamentals: widgets, event handlers, resource references, and layout managers (LinearLayout, TableLayout), culminating in small apps like a distance converter and a zip-code search. - **Middle (~32%–48%)**: Deepens layout control—GridLayout weights, spans, and constraint-based positioning—while assembling a working calculator app with stack-based logic and event handlers. - **Late (~48%–70%)**: Moves into user interaction (context menus, main menus, XML-defined menus), multiple activities, and file handling—resources, internal storage, and ordinary files. - **Ending (~70%–100%)**: Covers persistent data with SQLite (create, SELECT, INSERT, UPDATE, DELETE) and concurrency via threads and services, including local services and services backed by SQLite. 【Key Takeaways】 - **The book teaches by complete, runnable examples** (Opening): every concept arrives as a full app—converter, zip-code lookup, calculator—so you learn patterns you can adapt, not isolated syntax. - **Android UI is built from composable widgets and layout managers** (Early): understanding IDs, resource references (`@string/`, `@+id/`), and event handlers is the foundation for every screen you build. - **Layout choice drives behavior** (Middle): LinearLayout, TableLayout, GridLayout, and constraint-based positioning each solve different composition problems; weights and spans control how components fill space. - **Activities and menus structure user interaction** (Late): context menus, main menus, XML-defined menus, and multi-activity navigation form the backbone of real app flow. - **File and resource handling covers the storage spectrum** (Late): reading resources, ordinary files, and internal storage give you options depending on persistence needs. - **SQLite is the on-device database** (Ending): the book walks through creating a database and the full CRUD cycle, then integrates it with activities and services. - **Threads and services enable background work** (Ending): multiple service examples—including ringing the phone and local services—show how to keep long-running tasks off the UI thread. - **Platform matters less than you'd think** (Opening): examples are developed on Linux but run on Windows with minimal changes, mostly around file-system naming. 【Reading Tips】 - **Deep-read the early widget and layout chapters**—they establish the vocabulary (IDs, resources, event handlers) that every later example assumes. - **Skim the toolchain setup** if you already have Android Studio configured; the value is in the code, not the installation walkthrough. - **Type out and run the example apps** rather than reading them passively; the book's strength is executable code you can modify. - **Treat the exercises and problems as checkpoints**—they signal when you're ready to move from UI to storage and concurrency topics. - **Watch for OCR noise in the source**; some code fragments are garbled, so verify against your IDE's compiler rather than trusting the text verbatim. 【Coverage Limits】 The excerpts cover the book's structure and early-to-middle content in detail but thin out in the later chapters (SQLite, threads, services), so this guide's treatment of those topics relies on chapter headings and brief fragments rather than full exposition.