Android错误:尝试运行Gstreamer教程时为ndkBuild执行外部本机构建

Question

我试图在AndroidSudio3.5中运行gstreamer教程-5 (https://gitlab.freedesktop.org/gstreamer/gst-docs/tree/master/examples/tutorials/android)(https://gitlab.com/eduardoprado/gstreamer-tutorial5)，但得到以下错误：

ERROR: Cause: executing external native build for ndkBuild C:\Users\Downloads\gst_docs_master_examples_tutorials_android\examples\tutorials\android\android-tutorial-1\jni\Android.mk. 

我一直在跟踪gstreamer网站上的gstreamer教程以及堆栈溢出线程Gstreamer examples in Android Studio。

第一个目标是让gstreamer在android上运行。

有些线程的错误与路径目录中的空格有关，但我已经检查过了，所有文件夹都没有空白。下面是一些文件，我一直在使用和调整，以使本教程运行。

我还将windows环境变量GSTREAMER_ROOT_ANDROID设置为已解压缩的gstreamer二进制文件，并将其设置在android.mk文件中。

local.properties文件

## This file must *NOT* be checked into Version Control Systems,
# as it contains information specific to your local configuration.
#
# Location of the SDK. This is only used by Gradle.
# For customization when using a Version Control System, please read the
# header note.
#Mon Sep 09 08:16:12 EDT 2019
sdk.dir=C\:\\Users\\AppData\\Local\\Android\\Sdk
ndk.dir=C\:\\Users\\AppData\\Local\\Android\\Sdk\\ndk\\20.0.5594570

Android.mk

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE    := tutorial-5
LOCAL_SRC_FILES := tutorial-5.c
LOCAL_SHARED_LIBRARIES := gstreamer_android
LOCAL_LDLIBS := -llog -landroid
include $(BUILD_SHARED_LIBRARY)

GSTREAMER_ROOT_ANDROID := C\:\\gstreamer_android_binaries

ifndef GSTREAMER_ROOT_ANDROID
$(error GSTREAMER_ROOT_ANDROID is not defined!)
endif

ifeq ($(TARGET_ARCH_ABI),armeabi)
GSTREAMER_ROOT        := $(GSTREAMER_ROOT_ANDROID)/arm
else ifeq ($(TARGET_ARCH_ABI),armeabi-v7a)
GSTREAMER_ROOT        := $(GSTREAMER_ROOT_ANDROID)/armv7
else ifeq ($(TARGET_ARCH_ABI),arm64-v8a)
GSTREAMER_ROOT        := $(GSTREAMER_ROOT_ANDROID)/arm64
else ifeq ($(TARGET_ARCH_ABI),x86)
GSTREAMER_ROOT        := $(GSTREAMER_ROOT_ANDROID)/x86
else ifeq ($(TARGET_ARCH_ABI),x86_64)
GSTREAMER_ROOT        := $(GSTREAMER_ROOT_ANDROID)/x86_64
else
$(error Target arch ABI not supported: $(TARGET_ARCH_ABI))
endif

GSTREAMER_NDK_BUILD_PATH  := $(GSTREAMER_ROOT)/share/gst-android/ndk-build/
include $(GSTREAMER_NDK_BUILD_PATH)/plugins.mk
GSTREAMER_PLUGINS         := $(GSTREAMER_PLUGINS_CORE) $(GSTREAMER_PLUGINS_PLAYBACK) $(GSTREAMER_PLUGINS_CODECS) $(GSTREAMER_PLUGINS_NET) $(GSTREAMER_PLUGINS_SYS)
G_IO_MODULES              := gnutls
GSTREAMER_EXTRA_DEPS      := gstreamer-video-1.0
include $(GSTREAMER_NDK_BUILD_PATH)/gstreamer-1.0.mk

build.gradle (app)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 29
    buildToolsVersion "26.0.3"

    defaultConfig {
        applicationId "com.gst_sdk_tutorials.tutorial_5"
        minSdkVersion 14
        targetSdkVersion 29

        externalNativeBuild {
            ndkBuild {
                arguments "V=1"
            }
        }

        ndk {
            moduleName "tutorial-5"
            abiFilters 'x86', 'armeabi-v7a', 'arm64-v8a'
        }
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
        }
    }
    externalNativeBuild {
        ndkBuild {
            path 'src/main/jni/Android.mk'
        }
    }
}

build.gradle (项目)

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        jcenter()
        google()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.5.0'
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

gradle-wrapper.properties

#Mon Sep 09 14:10:17 EDT 2019
distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-all.zip

UPDATE将参数"V=1“添加到ndkBuild部分，并收到相同的错误：

ERROR: Cause: executing external native build for ndkBuild C:\Users\Downloads\gstreamer-tutorial5-master\app\src\main\jni\Android.mk

Answer 1

1. 下载整个教程目录(https://gitlab.freedesktop.org/gstreamer/gst-docs/)

2)打开Android ->打开现有的Android项目

1. 将整个android教程目录examples/tutorials/android作为一个项目打开

4)打开项目后，将屏幕左侧的视图更改为Project

1. 右键单击local.properties文件附近的->新->文件
2. 创建一个名为gradle.properties的新文件
3. 在新的gradle.properties文件中复制并粘贴以下代码。

# gstAndroidRoot can be set to point to the unpacked GStreamer android top-level directory
# containing each architecture in subdirectories, or else set the GSTREAMER_ROOT_ANDROID
# environment variable to that location
gstAndroidRoot=/gstreamer_android_binaries

注意，将gstAndroidRoot变量更改为您下载gstreamer二进制文件并解压缩它们的文件路径。https://gstreamer.freedesktop.org/data/pkg/android/可以从这里下载Gstreamer。

1. 现在我们需要设置NDK目录。确保下载并在SDK工具下启用NDK。

9)这将下载最新的NDK版本。但是，gstreamer目前不会使用最新的NDK构建。我们需要下载NDK修订版18b (releases)，如果您不使用NDK版本18，您可能会得到一个错误Android NDK: Assertion failure: SYSROOT_LINK is not defined . Stop. Open File。

1. 解压缩下载的NDK18b目录。
2. 将解压缩的android-ndk-r18b目录移到ndk文件夹位于AppData\Local\Android\Sdk\ndk下的位置。
3. 您现在应该在Android\Sdk\ndk中有两个文件夹。20.0.5594570 (or latest version)和android-ndk-r18b
4. 在android中，转到File ->项目结构
5. 在Android位置下，指向NDK 18目录。示例：C:\Users\AppData\Local\Android\Sdk\ndk\android-ndk-r18b
6. 连接一个电话与USB调试和运行！
7. 如果您在电话中出现错误，说明这是用于较旧版本的android。回到Android，切换到屏幕左侧的Android View。在Gradle Scripts下，为适当的教程选择build.gradle。更改compileSdkVersion 29、minSDKVersion 15和targetSDKVersion 29。

Answer 2

只需将项目移动到路径而不带空格。

/Users/myuser/Documents/android-project-folder示例

它帮助了我

Answer 3

请在build.gradle (App)上发表评论：

externalNativeBuild {
         ndkBuild {
             path 'src/main/jni/Android.mk'
         }
     }