android - 链接器命令在 Android Studio 中失败并退出代码 1？

Question

我在 android studio 中使用位图操作 native 库，但编译非常好，但运行时抛出链接器命令失败，退出代码 1(使用 -v 查看调用)

我被放置在 c 代码之后。

#include <jni.h>
#include <jni.h>
#include <android/log.h>
#include <stdio.h>
#include <android/bitmap.h>
#include <cstring>
#include <unistd.h>

#define  LOG_TAG    "DEBUG"
#define  LOGD(...)  __android_log_print(ANDROID_LOG_DEBUG,LOG_TAG,__VA_ARGS__)
#define  LOGE(...)  __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)

extern "C"
{
//store
JNIEXPORT jobject JNICALL Java_photoeditor_com_myapplication_MainActivity_jniStoreBitmapData(JNIEnv * env, jobject obj, jobject bitmap);
//get
JNIEXPORT jobject JNICALL Java_photoeditor_com_myapplication_MainActivity_jniGetBitmapFromStoredBitmapData(JNIEnv * env, jobject obj, jobject handle);
//free
JNIEXPORT void JNICALL Java_photoeditor_com_myapplication_MainActivity_jniFreeBitmapData(JNIEnv * env, jobject obj, jobject handle);
//rotate 90 degrees CCW
JNIEXPORT void JNICALL Java_photoeditor_com_myapplication_MainActivity_jniRotateBitmapCcw90(JNIEnv * env, jobject obj, jobject handle);
//rotate 90 degrees CW
JNIEXPORT void JNICALL Java_photoeditor_com_myapplication_MainActivity_jniRotateBitmapCw90(JNIEnv * env, jobject obj, jobject handle);
//crop
JNIEXPORT void JNICALL Java_photoeditor_com_myapplication_MainActivity_jniCropBitmap(JNIEnv * env, jobject obj, jobject handle, uint32_t left, uint32_t top, uint32_t right, uint32_t bottom);
//scale using nearest neighbor
JNIEXPORT void JNICALL Java_photoeditor_com_myapplication_MainActivity_jniScaleNNBitmap(JNIEnv * env, jobject obj, jobject handle, uint32_t newWidth, uint32_t newHeight);
}

class JniBitmap
{
public:
    uint32_t* _storedBitmapPixels;
    AndroidBitmapInfo _bitmapInfo;
    JniBitmap()
    {
        _storedBitmapPixels = NULL;
    }
};

/**crops the bitmap within to be smaller. note that no validations are done*/ //
JNIEXPORT void JNICALL Java_photoeditor_com_myapplication_MainActivity_jniCropBitmap(JNIEnv * env, jobject obj, jobject handle, uint32_t left, uint32_t top, uint32_t right, uint32_t bottom)
{
    JniBitmap* jniBitmap = (JniBitmap*) env->GetDirectBufferAddress(handle);
    if (jniBitmap->_storedBitmapPixels == NULL)
        return;
    uint32_t* previousData = jniBitmap->_storedBitmapPixels;
    uint32_t oldWidth = jniBitmap->_bitmapInfo.width;
    uint32_t newWidth = right - left, newHeight = bottom - top;
    uint32_t* newBitmapPixels = new uint32_t[newWidth * newHeight];
    uint32_t* whereToGet = previousData + left + top * oldWidth;
    uint32_t* whereToPut = newBitmapPixels;
    for (int y = top; y < bottom; ++y)
    {
        memcpy(whereToPut, whereToGet, sizeof(uint32_t) * newWidth);
        whereToGet += oldWidth;
        whereToPut += newWidth;
    }
    //done copying , so replace old data with new one
    delete[] previousData;
    jniBitmap->_storedBitmapPixels = newBitmapPixels;
    jniBitmap->_bitmapInfo.width = newWidth;
    jniBitmap->_bitmapInfo.height = newHeight;
}

/**rotates the inner bitmap data by 90 degress counter clock wise*/ //
JNIEXPORT void JNICALL Java_photoeditor_com_myapplication_MainActivity_jniRotateBitmapCcw90(JNIEnv * env, jobject obj, jobject handle)
{
    JniBitmap* jniBitmap = (JniBitmap*) env->GetDirectBufferAddress(handle);
    if (jniBitmap->_storedBitmapPixels == NULL)
        return;
    uint32_t* previousData = jniBitmap->_storedBitmapPixels;
    AndroidBitmapInfo bitmapInfo = jniBitmap->_bitmapInfo;
    uint32_t* newBitmapPixels = new uint32_t[bitmapInfo.height * bitmapInfo.width];
    int whereToGet = 0;
    // XY. ... ... ..X
    // ...>Y..>...>..Y
    // ... X.. .YX ...
    for (int x = 0; x < bitmapInfo.width; ++x)
        for (int y = bitmapInfo.height - 1; y >= 0; --y)
        {
            //take from each row (up to bottom), from left to right
            uint32_t pixel = previousData[whereToGet++];
            newBitmapPixels[bitmapInfo.width * y + x] = pixel;
        }
    delete[] previousData;
    jniBitmap->_storedBitmapPixels = newBitmapPixels;
    uint32_t temp = bitmapInfo.width;
    bitmapInfo.width = bitmapInfo.height;
    bitmapInfo.height = temp;
}

JNIEXPORT void JNICALL Java_photoeditor_com_myapplication_MainActivity_jniRotateBitmapCw90(JNIEnv * env, jobject obj, jobject handle)
{
    JniBitmap* jniBitmap = (JniBitmap*) env->GetDirectBufferAddress(handle);
    if (jniBitmap->_storedBitmapPixels == NULL)
        return;
    uint32_t* previousData = jniBitmap->_storedBitmapPixels;
    AndroidBitmapInfo bitmapInfo = jniBitmap->_bitmapInfo;
    uint32_t* newBitmapPixels = new uint32_t[bitmapInfo.height * bitmapInfo.width];
    int whereToGet = 0;
    // XY. ..X ... ...
    // ...>..Y>...>Y..
    // ... ... .YX X..
    for (int x = bitmapInfo.width - 1; x >= 0; --x)
        for (int y = 0; y < bitmapInfo.height; ++y)
        {
            //take from each row (up to bottom), from left to right
            uint32_t pixel = previousData[whereToGet++];
            newBitmapPixels[bitmapInfo.width * y + x] = pixel;
        }
    delete[] previousData;
    jniBitmap->_storedBitmapPixels = newBitmapPixels;
    uint32_t temp = bitmapInfo.width;
    bitmapInfo.width = bitmapInfo.height;
    bitmapInfo.height = temp;
}

/**free bitmap*/  //
JNIEXPORT void JNICALL Java_photoeditor_com_myapplication_MainActivity_jniFreeBitmapData(JNIEnv * env, jobject obj, jobject handle)
{
    JniBitmap* jniBitmap = (JniBitmap*) env->GetDirectBufferAddress(handle);
    if (jniBitmap->_storedBitmapPixels == NULL)
        return;
    delete[] jniBitmap->_storedBitmapPixels;
    jniBitmap->_storedBitmapPixels = NULL;
    delete jniBitmap;
}

/**restore java bitmap (from JNI data)*/  //
JNIEXPORT jobject JNICALL Java_photoeditor_com_myapplication_MainActivity_jniGetBitmapFromStoredBitmapData(JNIEnv * env, jobject obj, jobject handle)
{
    JniBitmap* jniBitmap = (JniBitmap*) env->GetDirectBufferAddress(handle);
    if (jniBitmap->_storedBitmapPixels == NULL)
    {
        LOGD("no bitmap data was stored. returning null...");
        return NULL;
    }
    //
    //creating a new bitmap to put the pixels into it - using Bitmap Bitmap.createBitmap (int width, int height, Bitmap.Config config) :
    //
    //LOGD("creating new bitmap...");
    jclass bitmapCls = env->FindClass("android/graphics/Bitmap");
    jmethodID createBitmapFunction = env->GetStaticMethodID(bitmapCls, "createBitmap", "(IILandroid/graphics/Bitmap$Config;)Landroid/graphics/Bitmap;");
    jstring configName = env->NewStringUTF("ARGB_8888");
    jclass bitmapConfigClass = env->FindClass("android/graphics/Bitmap$Config");
    jmethodID valueOfBitmapConfigFunction = env->GetStaticMethodID(bitmapConfigClass, "valueOf", "(Ljava/lang/String;)Landroid/graphics/Bitmap$Config;");
    jobject bitmapConfig = env->CallStaticObjectMethod(bitmapConfigClass, valueOfBitmapConfigFunction, configName);
    jobject newBitmap = env->CallStaticObjectMethod(bitmapCls, createBitmapFunction, jniBitmap->_bitmapInfo.width, jniBitmap->_bitmapInfo.height, bitmapConfig);
    //
    // putting the pixels into the new bitmap:
    //
    int ret;
    void* bitmapPixels;
    if ((ret = AndroidBitmap_lockPixels(env, newBitmap, &bitmapPixels)) < 0)
    {
        LOGE("AndroidBitmap_lockPixels() failed ! error=%d", ret);
        return NULL;
    }
    uint32_t* newBitmapPixels = (uint32_t*) bitmapPixels;
    int pixelsCount = jniBitmap->_bitmapInfo.height * jniBitmap->_bitmapInfo.width;
    memcpy(newBitmapPixels, jniBitmap->_storedBitmapPixels, sizeof(uint32_t) * pixelsCount);
    AndroidBitmap_unlockPixels(env, newBitmap);
    //LOGD("returning the new bitmap");
    return newBitmap;
}

/**store java bitmap as JNI data*/  //
JNIEXPORT jobject JNICALL Java_photoeditor_com_myapplication_MainActivity_jniStoreBitmapData(JNIEnv * env, jobject obj, jobject bitmap)
{
    AndroidBitmapInfo bitmapInfo;
    uint32_t* storedBitmapPixels = NULL;
    //LOGD("reading bitmap info...");
    int ret;
    if ((ret = AndroidBitmap_getInfo(env, bitmap, &bitmapInfo)) < 0)
    {
        LOGE("AndroidBitmap_getInfo() failed ! error=%d", ret);
        return NULL;
    }
    //LOGD("width:%d height:%d stride:%d", bitmapInfo.width, bitmapInfo.height, bitmapInfo.stride);
    if (bitmapInfo.format != ANDROID_BITMAP_FORMAT_RGBA_8888)
    {
        LOGE("Bitmap format is not RGBA_8888!");
        return NULL;
    }
    //
    //read pixels of bitmap into native memory :
    //
    //LOGD("reading bitmap pixels...");
    void* bitmapPixels;
    if ((ret = AndroidBitmap_lockPixels(env, bitmap, &bitmapPixels)) < 0)
    {
        LOGE("AndroidBitmap_lockPixels() failed ! error=%d", ret);
        return NULL;
    }
    uint32_t* src = (uint32_t*) bitmapPixels;
    storedBitmapPixels = new uint32_t[bitmapInfo.height * bitmapInfo.width];
    int pixelsCount = bitmapInfo.height * bitmapInfo.width;
    memcpy(storedBitmapPixels, src, sizeof(uint32_t) * pixelsCount);
    AndroidBitmap_unlockPixels(env, bitmap);
    JniBitmap *jniBitmap = new JniBitmap();
    jniBitmap->_bitmapInfo = bitmapInfo;
    jniBitmap->_storedBitmapPixels = storedBitmapPixels;
    return env->NewDirectByteBuffer(jniBitmap, 0);
}

/**scales the image using the fastest, simplest algorithm called "nearest neighbor" */ //
JNIEXPORT void JNICALL Java_photoeditor_com_myapplication_MainActivity_jniScaleNNBitmap(JNIEnv * env, jobject obj, jobject handle, uint32_t newWidth, uint32_t newHeight)
{
    JniBitmap* jniBitmap = (JniBitmap*) env->GetDirectBufferAddress(handle);
    if (jniBitmap->_storedBitmapPixels == NULL)
        return;
    uint32_t oldWidth = jniBitmap->_bitmapInfo.width;
    uint32_t oldHeight = jniBitmap->_bitmapInfo.height;
    uint32_t* previousData = jniBitmap->_storedBitmapPixels;
    uint32_t* newBitmapPixels = new uint32_t[newWidth * newHeight];
    int x2, y2;
    int whereToPut = 0;
    for (int y = 0; y < newHeight; ++y)
    {
        for (int x = 0; x < newWidth; ++x)
        {
            x2 = x * oldWidth / newWidth;
            if (x2 < 0)
                x2 = 0;
            else if (x2 >= oldWidth)
                x2 = oldWidth - 1;
            y2 = y * oldHeight / newHeight;
            if (y2 < 0)
                y2 = 0;
            else if (y2 >= oldHeight)
                y2 = oldHeight - 1;
            newBitmapPixels[whereToPut++] = previousData[(y2 * oldWidth) + x2];
            //same as : newBitmapPixels[(y * newWidth) + x] = previousData[(y2 * oldWidth) + x2];
        }
    }

    delete[] previousData;
    jniBitmap->_storedBitmapPixels = newBitmapPixels;
    jniBitmap->_bitmapInfo.width = newWidth;
    jniBitmap->_bitmapInfo.height = newHeight;
}

我正在使用 stacktrace 那个时间显示在我输入的异常之后

Cmakelists.txt 内部配置

cmake_minimum_required(VERSION 3.4.1)

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall")

add_library( # Sets the name of the library.
             JniBitmapOperations

             # Sets the library as a shared library.
             SHARED

             # Provides a relative path to your source file(s).
             # Associated headers in the same location as their source
             # file are automatically included.
             src/main/cpp/JniBitmapOperations.cpp )

find_library( # Sets the name of the path variable.
              log-lib
                    JniBitmapOperations
              # Specifies the name of the NDK library that
              # you want CMake to locate.
              log
              )
target_link_libraries( # Specifies the target library.

                       JniBitmapOperations

                       # Links the target library to the log library
                       # included in the NDK.
                       )

Android.mk文件内容

LOCAL_PATH := $(call my-dir)

#bitmap operations module
include $(CLEAR_VARS)

LOCAL_MODULE    := JniBitmapOperations
LOCAL_SRC_FILES := JniBitmapOperations.cpp
LOCAL_LDLIBS := -llog
LOCAL_LDFLAGS += -ljnigraphics

include $(BUILD_SHARED_LIBRARY)
APP_OPTIM := debug
LOCAL_CFLAGS := -g

#if you need to add more module, do the same as the one we started with (the one with the CLEAR_VARS)

添加调用 java jniBitmapHolder.java 文件，不再有进程仅编译和构建我的项目以抛出此异常。

import android.graphics.Bitmap;
import android.util.Log;

import java.nio.ByteBuffer;

public class JniBitmapHolder
  {
  ByteBuffer _handler =null;
  static
    {
    System.loadLibrary("JniBitmapOperations");
    }

  private native ByteBuffer jniStoreBitmapData(Bitmap bitmap);

  private native Bitmap jniGetBitmapFromStoredBitmapData(ByteBuffer handler);

  private native void jniFreeBitmapData(ByteBuffer handler);

  private native void jniRotateBitmapCcw90(ByteBuffer handler);

  private native void jniRotateBitmapCw90(ByteBuffer handler);

  private native void jniCropBitmap(ByteBuffer handler,final int left,final int top,final int right,final int bottom);

  private native void jniScaleNNBitmap(ByteBuffer handler,final int newWidth,final int newHeight);

  public JniBitmapHolder()
    {}

  public JniBitmapHolder(final Bitmap bitmap)
    {
    storeBitmap(bitmap);
    }

  public void storeBitmap(final Bitmap bitmap)
    {
    if(_handler!=null)
      freeBitmap();
    _handler=jniStoreBitmapData(bitmap);
    }

  public void rotateBitmapCcw90()
    {
    if(_handler==null)
      return;
    jniRotateBitmapCcw90(_handler);
    }

  public void rotateBitmapCw90()
    {
    if(_handler==null)
      return;
    jniRotateBitmapCw90(_handler);
    }

  public void cropBitmap(final int left,final int top,final int right,final int bottom)
    {
    if(_handler==null)
      return;
    jniCropBitmap(_handler,left,top,right,bottom);
    }

  public Bitmap getBitmap()
    {
    if(_handler==null)
      return null;
    return jniGetBitmapFromStoredBitmapData(_handler);
    }

  public Bitmap getBitmapAndFree()
    {
    final Bitmap bitmap=getBitmap();
    freeBitmap();
    return bitmap;
    }

  public void scaleBitmap(final int newWidth,final int newHeight)
    {
    if(_handler==null)
      return;
    jniScaleNNBitmap(_handler,newWidth,newHeight);
    }

  public void freeBitmap()
    {
    if(_handler==null)
      return;
    jniFreeBitmapData(_handler);
    _handler=null;
    }

  @Override
  protected void finalize() throws Throwable
    {
    super.finalize();
    if(_handler==null)
      return;
    Log.w("DEBUG","JNI bitmap wasn't freed nicely.please rememeber to free the bitmap as soon as you can");
    freeBitmap();
    }
  }

构建 gradle 文件配置。

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.2"
    useLibrary 'org.apache.http.legacy'
    defaultConfig {
        applicationId "com.itflash.whatsappstickers"
        minSdkVersion 18
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        multiDexEnabled true

        ndk {
            moduleName "JniBitmapOperations"
            ldLibs "log",  "jnigraphics"
            //abiFilters 'armeabi', 'armeabi-v7a', 'arm64-v8a', 'x86'
        }

        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        externalNativeBuild {
            cmake {
                cmake {
                    cppFlags "-frtti -fexceptions"
                    arguments '-DANDROID_PLATFORM=android-19', '-DANDROID_TOOLCHAIN=clang'
                }
            }
        }
    }
    packagingOptions {
        exclude 'META-INF/NOTICE' // will not include NOTICE file
        exclude 'META-INF/LICENSE' // will not include LICENSE file
        exclude 'META-INF/DEPENDENCIES'
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }
    dexOptions {
        incremental true
        javaMaxHeapSize "1536m"
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.google.android.gms:play-services:10.2.0'
    compile 'com.android.support:appcompat-v7:25.2.0'
    testCompile 'junit:junit:4.12'
}

Answer 1

链接器无法找到您使用的函数，即您必须手动指定库。在我看来，好像那应该是 libjnigraphics。

您是否在 Android.mk 中指定了 LOCAL_LDFLAGS += -ljnigraphics，如 this answer 所示？