[Android] Add android aar package (#416)

* [Android] Add Android build docs and demo (#26)

* [Backend] Add override flag to lite backend

* [Docs] Add Android C++ SDK build docs

* [Doc] fix android_build_docs typos

* Update CMakeLists.txt

* Update android.md

* [Doc] Add PicoDet Android demo docs

* [Doc] Update PicoDet Andorid demo docs

* [Doc] Update PaddleClasModel Android demo docs

* [Doc] Update fastdeploy android jni docs

* [Doc] Update fastdeploy android jni usage docs

* [Android] init fastdeploy android jar package

* [Backend] support int8 option for lite backend

* [Model] add Backend::Lite to paddle model

* [Backend] use CopyFromCpu for lite backend.

* [Android] package jni srcs and java api into aar

* Update infer.cc

* Update infer.cc

* [Android] Update package build.gradle

* [Android] Update android app examples

* [Android] update android detection app

java/android/fastdeploy/src/main/cpp/CMakeLists.txt

@@ -0,0 +1,60 @@
+# For more information about using CMake with Android Studio, read the
+# documentation: https://d.android.com/studio/projects/add-native-code.html
+
+# Sets the minimum version of CMake required to build the native library.
+cmake_minimum_required(VERSION 3.10.2)
+
+# Declares and names the project.
+project("fastdeploy_jni")
+
+# Creates and names a library, sets it as either STATIC
+# or SHARED, and provides the relative paths to its source code.
+# You can define multiple libraries, and CMake builds them for you.
+# Gradle automatically packages shared libraries with your APK.
+
+set(FastDeploy_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../../../libs/fastdeploy-android-0.5.0-shared-dev")
+
+find_package(FastDeploy REQUIRED)
+
+include_directories(.)
+include_directories(${FastDeploy_INCLUDE_DIRS})
+
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ffast-math -Ofast -Os -DNDEBUG -fomit-frame-pointer -fno-asynchronous-unwind-tables -fno-unwind-tables")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden -fvisibility-inlines-hidden -fdata-sections -ffunction-sections")
+set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -Wl,--gc-sections -Wl,-z,nocopyreloc")
+
+add_library(
+        fastdeploy_jni
+        SHARED
+        utils_jni.cc
+        bitmap_jni.cc
+        vision/results_jni.cc
+        vision/visualize_jni.cc
+        vision/detection/picodet_jni.cc
+        vision/classification/paddleclas_model_jni.cc)
+
+# Searches for a specified prebuilt library and stores the path as a
+# variable. Because CMake includes system libraries in the search path by
+# default, you only need to specify the name of the public NDK library
+# you want to add. CMake verifies that the library exists before
+# completing its build.
+
+find_library( # Sets the name of the path variable.
+        log-lib
+        # Specifies the name of the NDK library that
+        # you want CMake to locate.
+        log)
+
+# Specifies libraries CMake should link to your target library. You can link
+# multiple libraries, such as libraries you define in this build script,
+# prebuilt third-party libraries, or system libraries.
+
+target_link_libraries(
+        # Specifies the target library.
+        fastdeploy_jni
+        jnigraphics
+        ${FASTDEPLOY_LIBS}
+        GLESv2
+        EGL
+        ${log-lib}
+)