2021.04.08

cmake

app/CMakeLists.txt

@@ -0,0 +1,44 @@
+# 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 3.4.1)
+
+# 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.
+
+add_library( # Sets the name of the library.
+        native-lib
+
+        # Sets the library as a shared library.
+        SHARED
+
+        # Provides a relative path to your source file(s).
+        src/main/cpp/native-lib.cpp )
+
+# 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.
+        native-lib
+
+        # Links the target library to the log library
+        # included in the NDK.
+        ${log-lib} )

app/build.gradle

@@ -36,6 +36,12 @@ android {
         ]
     }
 
+    externalNativeBuild {
+        cmake {
+            path 'CMakeLists.txt'
+        }
+    }
+
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8
@@ -103,11 +109,11 @@ android {
     }
 
     buildTypes {
-        externalNativeBuild {
-            ndkBuild {
-                path 'src/main/jni/Android.mk'
-            }
-        }
+//        externalNativeBuild {
+//            ndkBuild {
+//                path 'src/main/jni/Android.mk'
+//            }
+//        }
         sourceSets.main {
             jni.srcDirs = []
             jniLibs.srcDirs = ['src/main/jniLibs']

app/src/main/cpp/native-lib.cpp

@@ -0,0 +1,15 @@
+//
+// Created by Administrator on 2021/4/8.
+//
+#include <jni.h>
+#include <string>
+
+extern "C"
+JNIEXPORT jstring
+
+JNICALL
+Java_com_tt_ttutils_jni_NDKTools_getStringFromNDK(
+        JNIEnv *env, jobject /* this */) {
+    std::string hello = "Hello from C++";
+    return env->NewStringUTF(hello.c_str());
+}

app/src/main/java/com/tt/ttutils/jni/NDKTools.java

@@ -2,7 +2,8 @@ package com.tt.ttutils.jni;
 
 public class NDKTools {
     static {
-        System.loadLibrary("NDKTools-jni");
+//        System.loadLibrary("NDKTools-jni");
+        System.loadLibrary("native-lib");
     }
 
     public static native String getStringFromNDK();