我在适用于Android的python kivy上有一个小型相机应用程序。它使用手机的前置摄像头拍照并显示图像。但是，一旦我开始在手机上测试该应用程序，就会遇到问题。
有3个电话：
1）小米mi a2（Android 9.0）
2）Redmi note 4x（Android 6.0）
3）Redmi note 3 pro（Android 8.1）
选择主摄像头时，该应用程序可在所有设备上运行，但如果选择前置摄像头，则仅在mi a2上运行。
手机上的错误日志报告问题出在resolution: (1280,720)中，但是无论我采用哪种解决方案，应用程序无论如何都会在这两个设备上崩溃。我在做什么错了，我该如何解决这个问题？
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivymd.theming import ThemeManager
import time
filename = ''
screenfour = ''
Builder.load_string("""
#:import MDFillRoundFlatButton kivymd.button.MDFillRoundFlatButton
#:import MDIconButton kivymd.button.MDIconButton
#:import MDFlatButton kivymd.button.MDFlatButton
#:import MDFloatingActionButton kivymd.button.MDFloatingActionButton
<ScreenManagement>:
ScreenOne:
name: "screen_one"
ScreenTwo:
name: "screen_two"
ScreenThree:
name: "screen_three"
id: entry
ScreenFour:
name: "screen_four"
<ScreenOne>:
canvas:
Rectangle:
pos: self.pos
size: self.size
FloatLayout:
MDIconButton:
icon: 'camera'
color: [1,1,1,1]
pos_hint: {'center_x':.50, 'center_y':.30}
on_press:
root.manager.transition.direction = 'up'
root.manager.transition.duration = 1
root.manager.current = 'screen_two'
<ScreenTwo>:
canvas:
Rectangle:
pos: self.pos
size: self.size
FloatLayout:
MDFillRoundFlatButton:
color: [1,1,1,1]
text: "Выбрать фон"
pos_hint: {'center_x':.50, 'center_y':.10}
on_press:
root.manager.transition.direction = 'up'
root.manager.transition.duration = 1
root.manager.current = 'screen_three'
MDIconButton:
icon: 'chevron-double-right'
pos_hint: {'center_x':.95, 'center_y':.10}
on_press:
root.manager.transition.direction = 'down'
root.manager.transition.duration = 1
root.manager.current = 'screen_one'
<ScreenThree>:
canvas:
Rectangle:
pos: self.pos
size: self.size
FloatLayout:
Widget:
Camera:
play: True
id: cam
index: 0
resolution: (1280,720)
size: (500,500)
MDFillRoundFlatButton:
text: "Сделать фото"
pos_hint: {'center_x':.50, 'center_y':.10}
on_press:
root.capture()
root.manager.current = 'screen_four'
MDIconButton:
icon: 'chevron-double-right'
pos_hint: {'center_x':.95, 'center_y':.10}
on_press:
root.manager.transition.direction = 'down'
root.manager.transition.duration = 1
root.manager.current = 'screen_two'
<ScreenFour>:
canvas:
Rectangle:
pos: self.pos
size: self.size
FloatLayout:
Image:
size: root.width, root.height
source: ''
id: imageWid
MDIconButton:
icon: 'chevron-double-right'
pos_hint: {'center_x':.95, 'center_y':.10}
on_press:
root.manager.transition.direction = 'down'
root.manager.transition.duration = 1
root.manager.current = 'screen_three'
""")
class ScreenOne(Screen):
pass
class ScreenTwo(Screen):
theme_cls = ThemeManager()
theme_cls.primary_palette = 'Blue'
main_widget = None
class ScreenThree(Screen):
theme_cls = ThemeManager()
theme_cls.primary_palette = 'Blue'
main_widget = None
def capture(self):
camera = self.ids['cam']
timestr = time.strftime("%Y%m%d_%H%M%S")
photo = camera.export_to_png("/storage/emulated/0/IMG_{}.png".format(timestr))
global filename, screenfour
filename = "/storage/emulated/0/IMG_{}.png".format(timestr)
screenfour.update()
class ScreenFour(Screen):
def __init__(self, **kwargs):
super(ScreenFour, self).__init__(**kwargs)
global screenfour
screenfour = self
def update(self, *args):
global filename
imageWidget = self.ids['imageWid']
imageWidget.source = filename
class ScreenManagement(ScreenManager):
pass
class Interface(App):
def build(self):
return ScreenManagement()
sample_app = Interface()
sample_app.run()
[app]
# (str) Title of your application
title = mycamapp
# (str) Package name
package.name = mycamapplication
# (str) Package domain (needed for android/ios packaging)
package.domain = org.camcamcamapp
# (str) Source code where the main.py live
source.dir = .
# (list) Source files to include (let empty to include all the files)
source.include_exts = py,png,jpg,kv,atlas
# (list) List of inclusions using pattern matching
#source.include_patterns = assets/*,images/*.png
# (list) Source files to exclude (let empty to not exclude anything)
#source.exclude_exts = spec
# (list) List of directory to exclude (let empty to not exclude anything)
#source.exclude_dirs = tests, bin
# (list) List of exclusions using pattern matching
#source.exclude_patterns = license,images/*/*.jpg
# (str) Application versioning (method 1)
version = 1.0
# (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 = python3,kivy,numpy,opencv,git+https://github.com/HeaTTheatR/KivyMD.git,android
# (str) Custom source folders for requirements
# Sets custom source for any requirements with recipes
# requirements.source.kivy = ../../kivy
# (list) Garden requirements
#garden_requirements =
# (str) Presplash of the application
#presplash.filename = %(source.dir)s/data/presplash.upng
# (str) Icon of the application
#icon.filename = %(source.dir)s/data/icon.png
# (str) Supported orientation (one of landscape, sensorLandscape, portrait or all)
orientation = all
# (list) List of service to declare
#services = NAME:ENTRYPOINT_TO_PY,NAME2:ENTRYPOINT2_TO_PY
#
# OSX Specific
#
#
# author = © Copyright Info
# change the major version of python used by the app
osx.python_version = 3.7.3
# Kivy version to use
osx.kivy_version = 1.10.1
#
# Android specific
#
# (bool) Indicate if the application should be fullscreen or not
fullscreen = 0
# (string) Presplash background color (for new android toolchain)
# Supported formats are: #RRGGBB #AARRGGBB or one of the following names:
# red, blue, green, black, white, gray, cyan, magenta, yellow, lightgray,
# darkgray, grey, lightgrey, darkgrey, aqua, fuchsia, lime, maroon, navy,
# olive, purple, silver, teal.
#android.presplash_color = #FFFFFF
# (list) Permissions
android.permissions = INTERNET,CAMERA,WRITE_EXTERNAL_STORAGE,READ_EXTERNAL_STORAGE
# (int) Target Android API, should be as high as possible.
android.api = 28
# (int) Minimum API your APK will support.
android.minapi = 21
# (int) Android SDK version to use
android.sdk = 29
# (str) Android NDK version to use
android.ndk = 17c
# (int) Android NDK API to use. This is the minimum API your app will support, it should usually match android.minapi.
#android.ndk_api = 21
# (bool) Use --private data storage (True) or --dir public storage (False)
#android.private_storage = True
# (str) Android NDK directory (if empty, it will be automatically downloaded.)
#android.ndk_path =
# (str) Android SDK directory (if empty, it will be automatically downloaded.)
#android.sdk_path =
# (str) ANT directory (if empty, it will be automatically downloaded.)
#android.ant_path =
# (bool) If True, then skip trying to update the Android sdk
# This can be useful to avoid excess Internet downloads or save time
# when an update is due and you just want to test/build your package
# android.skip_update = False
# (bool) If True, then automatically accept SDK license
# agreements. This is intended for automation only. If set to False,
# the default, you will be shown the license when first running
# buildozer.
# android.accept_sdk_license = False
# (str) Android entry point, default is ok for Kivy-based app
#android.entrypoint = org.renpy.android.PythonActivity
# (list) Pattern to whitelist for the whole project
#android.whitelist =
# (str) Path to a custom whitelist file
#android.whitelist_src =
# (str) Path to a custom blacklist file
#android.blacklist_src =
# (list) List of Java .jar files to add to the libs so that pyjnius can access
# their classes. Don't add jars that you do not need, since extra jars can slow
# down the build process. Allows wildcards matching, for example:
# OUYA-ODK/libs/*.jar
#android.add_jars = foo.jar,bar.jar,path/to/more/*.jar
# (list) List of Java files to add to the android project (can be java or a
# directory containing the files)
#android.add_src =
# (list) Android AAR archives to add (currently works only with sdl2_gradle
# bootstrap)
#android.add_aars =
# (list) Gradle dependencies to add (currently works only with sdl2_gradle
# bootstrap)
#android.gradle_dependencies =
# (list) Java classes to add as activities to the manifest.
#android.add_activites = com.example.ExampleActivity
# (str) python-for-android branch to use, defaults to master
p4a.branch = master
# (str) OUYA Console category. Should be one of GAME or APP
# If you leave this blank, OUYA support will not be enabled
#android.ouya.category = GAME
# (str) Filename of OUYA Console icon. It must be a 732x412 png image.
#android.ouya.icon.filename = %(source.dir)s/data/ouya_icon.png
# (str) XML file to include as an intent filters in <activity> tag
#android.manifest.intent_filters =
# (str) launchMode to set for the main activity
#android.manifest.launch_mode = standard
# (list) Android additional libraries to copy into libs/armeabi
#android.add_libs_armeabi = libs/android/*.so
#android.add_libs_armeabi_v7a = libs/android-v7/*.so
#android.add_libs_x86 = libs/android-x86/*.so
#android.add_libs_mips = libs/android-mips/*.so
# (bool) Indicate whether the screen should stay on
# Don't forget to add the WAKE_LOCK permission if you set this to True
#android.wakelock = False
# (list) Android application meta-data to set (key=value format)
#android.meta_data =
# (list) Android library project to add (will be added in the
# project.properties automatically.)
#android.library_references =
# (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
android.arch = armeabi-v7a
#
# Python for android (p4a) specific
#
# (str) python-for-android git clone directory (if empty, it will be automatically cloned from github)
p4a.source_dir = /home/max/desktop/python-for-android-master/
# (str) The directory in which python-for-android should look for your own build recipes (if any)
#p4a.local_recipes =
# (str) Filename to the hook for p4a
#p4a.hook =
# (str) Bootstrap to use for android builds
# p4a.bootstrap = sdl2
# (int) port number to specify an explicit --port= p4a argument (eg for bootstrap flask)
#p4a.port =
#
# iOS specific
#
# (str) Path to a custom kivy-ios folder
#ios.kivy_ios_dir = ../kivy-ios
# Alternately, specify the URL and branch of a git checkout:
ios.kivy_ios_url = https://github.com/kivy/kivy-ios
ios.kivy_ios_branch = master
# Another platform dependency: ios-deploy
# Uncomment to use a custom checkout
#ios.ios_deploy_dir = ../ios_deploy
# Or specify URL and branch
ios.ios_deploy_url = https://github.com/phonegap/ios-deploy
ios.ios_deploy_branch = 1.7.0
# (str) Name of the certificate to use for signing the debug version
# Get a list of available identities: buildozer ios list_identities
#ios.codesign.debug = "iPhone Developer: <lastname> <firstname> (<hexstring>)"
# (str) Name of the certificate to use for signing the release version
#ios.codesign.release = %(ios.codesign.debug)s
[buildozer]
# (int) Log level (0 = error only, 1 = info, 2 = debug (with command output))
log_level = 2
# (int) Display warning if buildozer is run as root (0 = False, 1 = True)
warn_on_root = 0
# (str) Path to build artifact storage, absolute or relative to spec file
# build_dir = ./.buildozer
# (str) Path to build output (i.e. .apk, .ipa) storage
# bin_dir = ./bin
# -----------------------------------------------------------------------------
# List as sections
#
# You can define all the "list" as [section:key].
# Each line will be considered as a option to the list.
# Let's take [app] / source.exclude_patterns.
# Instead of doing:
#
#[app]
#source.exclude_patterns = license,data/audio/*.wav,data/images/original/*
#
# This can be translated into:
#
#[app:source.exclude_patterns]
#license
#data/audio/*.wav
#data/images/original/*
#
# -----------------------------------------------------------------------------
# Profiles
#
# You can extend section / key with a profile
# For example, you want to deploy a demo version of your application without
# HD content. You could first change the title to add "(demo)" in the name
# and extend the excluded directories to remove the HD content.
#
#[app@demo]
#title = My Application (demo)
#
#[app:source.exclude_patterns@demo]
#images/hd/*
#
# Then, invoke the command line with the "demo" profile:
#
#buildozer --profile demo android debug
04-12 21:38:23.364 9168 9202 I python : kivy.lang.builder.BuilderException: Parser: File "<inline>", line 59:
04-12 21:38:23.364 9168 9202 I python : ...
04-12 21:38:23.364 9168 9202 I python : 57: id: cam
04-12 21:38:23.364 9168 9202 I python : 58: index: 1
04-12 21:38:23.364 9168 9202 I python : >> 59: resolution: (640,480)
04-12 21:38:23.365 9168 9202 I python : 60: size: dp(500), dp(500)
04-12 21:38:23.365 9168 9202 I python : 61: AnchorLayout:
04-12 21:38:23.365 9168 9202 I python : ...
04-12 21:38:23.365 9168 9202 I python : JavaException: JVM exception occurred: Fail to connect to camera service
答案 0 :(得分：0)
将size: (500,500)替换为size: dp(500), dp(500)
Builder.load_string("""
#:import dp kivy.metrics.dp
...
<ScreenThree>:
canvas:
Rectangle:
pos: self.pos
size: self.size
FloatLayout:
Widget:
Camera:
play: True
id: cam
index: 0
resolution: (1280,720)
size: dp(500), dp(500)
dp与密度无关的像素-基于像素的抽象单位 屏幕的物理密度。 density为1时，1dp等于 到1像素。在更高密度的屏幕上运行时，像素数 用来绘制1dp的比例会放大到适合屏幕尺寸的 dpi，反之则降低dpi。 dp与像素的比例将 随屏幕密度变化，但不一定直接变化 比例。使用dp单元是制作视图的简单解决方案 布局中的尺寸会针对不同的屏幕正确调整大小 密度。换句话说，它为现实世界提供了一致性 不同设备上的用户界面大小。