作为新手，我正在尝试制作一个在移动设备上运行良好的应用程序。这是示例应用程序的使用代码。
Android resource compilation failed
Output: E:\android-architecture-components-master\android-architecture-components-master\SQLite2\app\src\main\res\layout\activity_main.xml:9: error: unbound prefix.
Command: C:\Users\dell\.gradle\caches\transforms-1\files-1.1\aapt2-3.2.1-4818971-windows.jar\a3fe73bf8fd171960fd7f818f6c92fe4\aapt2-3.2.1-4818971-windows\aapt2.exe compile --legacy \
-o \
E:\android-architecture-components-master\android-architecture-components-master\SQLite2\app\build\intermediates\res\merged\debug \
E:\android-architecture-components-master\android-architecture-components-master\SQLite2\app\src\main\res\layout\activity_main.xml
Daemon: AAPT2 aapt2-3.2.1-4818971-windows Daemon #2