随着Android手机用户的不断增加，Android应用的开发变得越来越受欢迎。不仅Java等编程语言能够开发Android应用，Python也有自己的一套方法来进行Android应用的开发。Python能够让开发者更加方便、快速地创建Android应用程序，下面就来详细介绍一下Python的Android应用界面编写方法。
一、PyQt5简介
PyQt是Python语言的GUI编程工具包，它是做为对Qt界面开发工具的Python-binding实现。PyQt5是PyQt的最新版本，支持Python3，支持Python常用的图形界面开发工具Qt5。因此，如果要开发Python编写的Android应用界面，推荐使用PyQt5。
二、制作Android应用程序界面的方法
1. 安装Python-for-Android以及PyQt5
首先，需要在Android手机上安装Python-for-Android、PyQt5以及QtforPython（也称为PySide2），这样才能确保Python 能够与Qt及其它库相互配合。可以通过下面的命令行来安装：
$ pip install PySide2 $ pip install PyQt5 $ pip install android
2. 编写Python代码
通过PyQt5，可以使用Python编写Android应用程序的界面。以下是一个简单的Python程序:
from PySide2.QtCore import *
from PySide2.QtGui import *
from PySide2.QtWidgets import *
class MyWidget(QWidget):
def __init__(self):
super().__init__()
self.setWindowTitle('Hello World')
layout = QVBoxLayout(self)
label = QLabel('Hello World', self)
label.setAlignment(Qt.AlignCenter)
layout.addWidget(label)
if __name__ == '__main__':
app = QApplication()
widget = MyWidget()
widget.show()
app.exec_()
这个程序简单地创建了一个窗口和一个标签，在标签中显示“Hello World”文本。
3. 打包发布应用
使用buildozer打包PyQt5应用程序为Android应用程序，可以使用一个名为buildozer.spec文件中的一组指令。这个文件包括应用程序的所有来源和组件的配置。以下是buildozer.spec文件中必需的指令范例：
[app] # (str) Title of your application title = My Application # (str) Package name package.name = myapp # (str) Package domain (needed for android/ios packaging) package.domain = org.test # (str) Source code where the main.py live source.dir = . # (list) List of source files to includes into the package source.include_exts = py,png,jpg,kv,atlas # (list) List of inclusions using pattern matching #source.include_patterns = assets/*,images/*.png # (list) List of exclusions using pattern matching #source.exclude_patterns = tests/*,bin/*/*,.*/*,*/RCS/* # (str) Application versioning (method 1) # version = 0.1 # (str) Application versioning (method 2) # version.regex = __version__ = ['"](.*)['"] # version.filename = %(source.dir)s/main.py # (list) Application requirements # comma separated e.g. requirements = sqlite3,kivy #requirements = kivy # (str) Custom source folders for requirements # Sets custom source for any requirements with recipes # If it's one of our recipes, will set the recipe #requirements.source.kivy = ../../kivy # (list) Garden Requirements #garden_requirements = # (str) Presplash of the application #presplash.filename = %(source.dir)s/data/presplash.png # (str) Icon of the application #icon.filename = %(source.dir)s/data/icon.png # (str) Supported orientation (one of landscape, sensorLandscape, portrait or all) orientation = portrait # (bool) Indicate if the application should be fullscreen or not fullscreen = 0 # (bool) Try to bypass Android permissions android.permissions = INTERNET # (str) Primary color of the application android.primary_color = #50D1AA # (str) Secondary color of the application android.secondary_color = #50D1BB # (str) Accent color of the application #android.accent_color = # (bool) Show or not the debug panel #android.debug = False # (list) Permissions #android.permissions = # (list) features (adds uses-feature -tags to manifest) #android.features = # (str) android logcat filters to use #android.logcat_filters = *:S python:D # (bool) Copy library instead of making a libpymodules.so #android.copy_libs = 1 # (str) The Android arch to build for, choices: armeabi-v7a, arm64-v8a, x86, x86_64 # Defaults to armeabi-v7a for backwards compatibility. android.arch = armeabi-v7a # (str) Sequence of one or more ant commands to apply before packaging #android.prebuild_cmd = # (str) Path to a custom toolchain if defined. It must contain the following four files: # bin/arm-linux-androideabi-gcc # bin/arm-linux-androideabi-g++ # include/python2.7/pyconfig.h # libs/armeabi-v7a/libpython2.7.so #android.toolchain = /opt/android-toolchain-arm # (str) Path to a custom NDK directory (if empty, it's assumed the NDK is in PATH) #android.ndk_path = # (list) Flags for the compiler #android.custom_cflags = # (list) Linker flags #android.custom_ldflags = # (list) Othe pyinstaller bootloader options (https://pythonhosted.org/PyInstaller/usage.html) #p4a.bootloader.bootces = ces64 #p4a.bootloader.name = mybootloader # (int) Number of workers to run the python for android build process #android.numeric_version = 0 # (str) The version of the NDK to use #android.ndk_version = 'r9c' # (int) Which toolchain to use. Choices: 0 (default), 1 or 2 #android.toolchain_version = 0 # (str) If defined, set the ANDROIDSDK environment variable to the path #android.sdk_path = # (str) If defined, set the ANDROIDNDK environment variable to the path #android.ndk_path = /usr/local/android-ndk-r9 # (str) If defined, set the ANDROIDAPI environment variable to the API level android.api = 27 # (str) NDK extra options to specify #android.ndk_options = "ndk-toolchain=clang" # (str) The branch of sdl2 to use #android.sdl2_branch = master # (bool) If True, then no local python is built, and the native libs # are copied from the host. #android.copy_local_libs = False # (list) Whitelist of packages to include from the Python build #android.whitelist = # (list) Blacklist of packages to ommit from the build #android.blacklist = # (list) List of Java .jar files to add to the build of the final .apk. #android.add_jars = foo.jar,bar.jar,path/to/more.jar # (list) List of Java folders to add to the build of the final .apk. #android.add_java_dir = foo,bar,path/to/more # (list) A list of Java classes to compile against, e.g. org.w3c.dom #android.add_compile_exts = my_java_ext # (str) Path to a custom prebuilt .so/.a to add to the libs/armeabi. Can be in tree or external. #android.add_libs_armeabi = foo.so,bar.a,path/to/more # (bool) Use –bootstrap to attempt to build the bootstrap dependencies #android.bootstrap = sdl2 # (str) work around for alleged SDL2 bug on android # see http://www.kivy.org/docs/helP/android.html#buildozer-spec #android.setup_mode = False
三、总结
通过以上所述方法，我们可以快速的开发一个Python编写的Android应用程序，运用Python语言，加上强大的PyQt5工具包等，该方法能够在程序开发过程中大幅提升开发效率，同时还能让Python这门语言能够在Android应用开发中大展身手。
