Delphi/Android 在哪里搜索本地语言库?

Where does Delphi/Android search for a native language library?(Delphi/Android 在哪里搜索本地语言库?)

问题描述

我想为 Delphi Android 应用程序添加 MIDI 功能.MIDI 可通过可通过 Android NDK 访问的 SoniVox 库获得.这里可以找到此驱动程序的示例.该驱动程序是用 C 编写的，使用 NDK 可以创建一个可以通过 System.loadLibrary 调用访问的本地语言库.

I want to add MIDI capabilities to Delphi Android apps. MIDI is available via the SoniVox library which can be accessed via the Android NDK. An example of this driver can be found here. The driver is written in C, with the NDK it is possible to create a native language library which can be accessed via a System.loadLibrary call.

  //  MidiDriver - An Android Midi Driver.
  //  Copyright (C) 2013    Bill Farmer
  //  Bill Farmer    william j farmer [at] yahoo [dot] co [dot] uk.

  #include <jni.h>

  // for EAS midi
  #include "eas.h"
  #include "eas_reverb.h"

  // determines how many EAS buffers to fill a host buffer
  #define NUM_BUFFERS 4

  // EAS data
  static EAS_DATA_HANDLE pEASData;
  const S_EAS_LIB_CONFIG *pLibConfig;
  static EAS_PCM *buffer;
  static EAS_I32 bufferSize;
  static EAS_HANDLE midiHandle;

  // init EAS midi
  jint
  Java_org_drivers_midioutput_MidiDriver_init(JNIEnv *env,
                          jobject clazz)
  {
      EAS_RESULT result;

      // get the library configuration
      pLibConfig = EAS_Config();
      if (pLibConfig == NULL || pLibConfig->libVersion != LIB_VERSION)
    return 0;

      // calculate buffer size
      bufferSize = pLibConfig->mixBufferSize * pLibConfig->numChannels *
    NUM_BUFFERS;

      // init library
      if ((result = EAS_Init(&pEASData)) != EAS_SUCCESS)
    return 0;

      // select reverb preset and enable
      EAS_SetParameter(pEASData, EAS_MODULE_REVERB, EAS_PARAM_REVERB_PRESET,
             EAS_PARAM_REVERB_CHAMBER);
      EAS_SetParameter(pEASData, EAS_MODULE_REVERB, EAS_PARAM_REVERB_BYPASS,
             EAS_FALSE);

      // open midi stream
      if (result = EAS_OpenMIDIStream(pEASData, &midiHandle, NULL) !=
    EAS_SUCCESS)
      {
    EAS_Shutdown(pEASData);
    return 0;
      }

      return bufferSize;
  }

  // midi config
  jintArray
  Java_org_drivers_midioutput_MidiDriver_config(JNIEnv *env,
                            jobject clazz)
  {
      jboolean isCopy;

      if (pLibConfig == NULL)
    return NULL;

      jintArray configArray = (*env)->NewIntArray(env, 4);

      jint *config = (*env)->GetIntArrayElements(env, configArray, &isCopy);

      config[0] = pLibConfig->maxVoices;
      config[1] = pLibConfig->numChannels;
      config[2] = pLibConfig->sampleRate;
      config[3] = pLibConfig->mixBufferSize;

      (*env)->ReleaseIntArrayElements(env, configArray, config, 0);

      return configArray;
  }

  // midi render
  jint
  Java_org_drivers_midioutput_MidiDriver_render(JNIEnv *env,
                            jobject clazz,
                            jshortArray shortArray)
  {
      jboolean isCopy;
      EAS_RESULT result;
      EAS_I32 numGenerated;
      EAS_I32 count;
      jsize size;

      // jbyte* GetByteArrayElements(jbyteArray array, jboolean* isCopy)
      // void ReleaseByteArrayElements(jbyteArray array, jbyte* elems,

      // void* GetPrimitiveArrayCritical(JNIEnv*, jarray, jboolean*);
      // void ReleasePrimitiveArrayCritical(JNIEnv*, jarray, void*, jint);

      if (pEASData == NULL)
    return 0;

      buffer =
    (EAS_PCM *)(*env)->GetShortArrayElements(env, shortArray, &isCopy);

      size = (*env)->GetArrayLength(env, shortArray);

      count = 0;
      while (count < size)
      {
    result = EAS_Render(pEASData, buffer + count,
                pLibConfig->mixBufferSize, &numGenerated);
    if (result != EAS_SUCCESS)
        break;

    count += numGenerated * pLibConfig->numChannels;
      }

      (*env)->ReleaseShortArrayElements(env, shortArray, buffer, 0);

      return count;
  }

  // midi write
  jboolean
  Java_org_drivers_midioutput_MidiDriver_write(JNIEnv *env,
                           jobject clazz,
                           jbyteArray byteArray)
  {
      jboolean isCopy;
      EAS_RESULT result;
      jint length;
      EAS_U8 *buf;

      if (pEASData == NULL || midiHandle == NULL)
    return JNI_FALSE;

      buf = (EAS_U8 *)(*env)->GetByteArrayElements(env, byteArray, &isCopy);
      length = (*env)->GetArrayLength(env, byteArray);

      result = EAS_WriteMIDIStream(pEASData, midiHandle, buf, length);

      (*env)->ReleaseByteArrayElements(env, byteArray, buf, 0);

      if (result != EAS_SUCCESS)
    return JNI_FALSE;

      return JNI_TRUE;
  }

  // shutdown EAS midi
  jboolean
  Java_org_drivers_midioutput_MidiDriver_shutdown(JNIEnv *env,
                              jobject clazz)
  {
      EAS_RESULT result;

      if (pEASData == NULL || midiHandle == NULL)
    return JNI_FALSE;

      if ((result = EAS_CloseMIDIStream(pEASData, midiHandle)) != EAS_SUCCESS)
      {
    EAS_Shutdown(pEASData);
    return JNI_FALSE;
      }

      if ((result = EAS_Shutdown(pEASData)) != EAS_SUCCESS)
    return JNI_FALSE;

      return JNI_TRUE;
  }

我使用 Eclipse 创建了一个 Android 应用程序，将 MidiDriver 添加为本地库，并让所有内容都启动并运行.有了这个驱动程序，我的应用程序中就有了 MIDI 功能.您将在下面找到 MidiDriver 代码的概要.

I created an Android app with Eclipse, added the MidiDriver as a native library and got everything up and running. With this driver I have MIDI capabilities in my app. The outline of the MidiDriver code you will find below.

  //  MidiDriver - An Android Midi Driver.
  //  Copyright (C) 2013    Bill Farmer
  //  Bill Farmer    william j farmer [at] yahoo [dot] co [dot] uk.

  package  org.drivers.midioutput;

  import java.io.File;

  import android.media.AudioFormat;
  import android.media.AudioManager;
  import android.media.AudioTrack;
  import android.util.Log;

  // MidiDriver

  public class MidiDriver implements Runnable
  {
      private static final int SAMPLE_RATE = 22050;
      private static final int BUFFER_SIZE = 4096;

      private Thread thread;
      private AudioTrack audioTrack;

      private OnMidiStartListener listener;

      private short buffer[];

      // Constructor

      public MidiDriver ()
      {
         Log.d ("midi", ">> MidiDriver started");
      }

      public void start ()
      {
    // Start the thread
         thread = new Thread (this, "MidiDriver");
         thread.start ();
      } // start //

      @Override
      public void run ()
      {
          processMidi ();
      } // run //

      public void stop ()
      {
        Thread t = thread;
        thread = null;

        // Wait for the thread to exit

        while (t != null && t.isAlive ())
            Thread.yield ();
      } // stop //

      // Process MidiDriver

      private void processMidi ()
      {
        int status = 0;
        int size = 0;

        // Init midi

        if ((size = init()) == 0)
            return;

        buffer = new short [size];

        // Create audio track

        audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, SAMPLE_RATE,
                        AudioFormat.CHANNEL_OUT_STEREO,
                        AudioFormat.ENCODING_PCM_16BIT,
                        BUFFER_SIZE, AudioTrack.MODE_STREAM);
        if (audioTrack == null)
        {
            shutdown ();
            return;
        } // if

        // Call listener

        if (listener != null)
            listener.onMidiStart();

        // Play track

        audioTrack.play();

        // Keep running until stopped

        while (thread != null)
        {
            // Render the audio

            if (render(buffer) == 0)
               break;

            // Write audio to audiotrack

            status = audioTrack.write(buffer, 0, buffer.length);

            if (status < 0)
               break;
        } // while

        // Render and write the last bit of audio

        if (status > 0)
            if (render(buffer) > 0)
               audioTrack.write(buffer, 0, buffer.length);

        // Shut down audio

        shutdown();
        audioTrack.release();
      } // processMidi //

      public void setOnMidiStartListener (OnMidiStartListener l)
      {
         listener = l;
      } // setOnMidiStartListener //

      public static void load_lib (String libName) 
      {
         File file = new File (libName);

         if (file.exists ()) 
         {
             System.load (libName);
         } else 
         {
             System.loadLibrary (libName);
         }
     }    // Listener interface

      public interface OnMidiStartListener
      {
         public abstract void onMidiStart ();
      } // OnMidiStartListener //

      // Native midi methods

      private native int     init ();
      public  native int []  config ();
      private native int     render (short a []);
      public  native boolean write (byte a []);
      private native boolean shutdown ();

      // Load midi library

      static
      {
         System.loadLibrary ("midi");
      }
  }

接下来我测试了 JNI 接口，看看我是否可以通过 JNI 从 Delphi 访问 Java 类.也没有问题.所以理论上我应该能够通过 Java 接口访问 MidiDriver:酷！我将 MidiDriver 包装在另一个 Java 类中:MIDI_Output 以便在内部处理接口(我不知道如何在 Delphi 中接口 Java 接口.MIDI_Output 创建一个 MidiDriver 实例并在必要时从 MidiDriver 调用函数.这一切都很好用从 Eclipse 运行.MIDI_Output 的某些部分如下:

Next I tested the JNI interface to see whether I could access Java classes from Delphi via JNI. No problem either. So theoretically I should be able to access the MidiDriver via a Java interface: cool! I wrapped MidiDriver in a another Java class: MIDI_Output in order to handle the interface internally (I have no idea how to interface a Java interface in Delphi. MIDI_Output creates an instance of MidiDriver and calls functions from MidiDriver when necessary. This all works great when running from Eclipse. Some parts of MIDI_Output below:

  package org.drivers.midioutput;

  import java.io.IOException;

  import org.drivers.midioutput.MidiDriver.OnMidiStartListener;

  import android.media.MediaPlayer;
  import android.os.Environment;
  import android.util.Log;

  public class MIDI_Output implements OnMidiStartListener
  {
     protected MidiDriver midi_driver;
     protected MediaPlayer media_player;

     public MIDI_Output ()
     {
        // Create midi driver
        Log.d ("midi", ">> Before initializing MIDI driver version 1");

        midi_driver = new MidiDriver();

  // Set onmidistart listener to this class

        if (midi_driver != null)
            midi_driver.setOnMidiStartListener (this);
     } // MIDI_Output () //

  protected void putShort (int m, int n, int v)
  {
     if (midi_driver != null)
     {
       byte msg [] = new byte [3];

       msg [0] = (byte) m;
       msg [1] = (byte) n;
       msg [2] = (byte) v;

       midi_driver.write (msg);
     } // if
  } // putShort //

  // and much more code
  // ...   

在上面的例子中，putShort 从 MidiDriver 调用函数 write，这是一个在本地库中定义的函数.这一切在 Java 中都可以正常工作，但在 Dellphi 中，你可能已经猜到了，这有点难.为了更详细地显示调用链，我需要在 Delphi 中使用这整个装置，请参见下图.

In the example above putShort calls function write from MidiDriver which is a function defined in the native library. This all works fine in Java but in Dellphi practice is a little harder as you might have guessed. To show in more detail the call chain I need to use this whole contraption in Delphi see the image below.

在 libsonivox(在 /system/lib 中找到)可以找到函数 EAS_WriteMidiStream，它是从函数 write 调用的libmidi.so 中的 (在任何地方都可以找到，也可以在 /system/lib 和 /vendor/lib 中找到)，这是声明的在 MidiDriver.java 在 MIDI_Output.apk 中，从 MIDI_Output.java 调用它创建一个 new MidiDriver 并引用到同一包的函数 putShort 中的 midi_driver.write (...).最后 putShort 应该在 Delphi 中调用，但它永远不会到达那里.

In libsonivox (found in /system/lib) the function EAS_WriteMidiStream can be found, which is called from function write in libmidi.so (found everywhere, but also in /system/lib and /vendor/lib), which is declared in MidiDriver.java in MIDI_Output.apk which is called from MIDI_Output.java which creates a new MidiDriver and refers to midi_driver.write (...) in function putShort of the same package. Finally putShort should be called in Delphi but it never gets there.

当 MIDI_Output 创建试图加载 midi 库的 new MidiDriver 时，它被中止.程序无法加载库midi".我运行 adb -d logcat 来查看发生了什么，输出如下所示.android 屏幕上显示的错误消息被突出显示.

It is aborted when MIDI_Output create the new MidiDriver which tries to load the midi library. The program is not able to load the library "midi". I ran adb -d logcat to see what happens and the output is shown below. The error message that is shown on the android screen is highlighted.

  D/dalvikvm( 5251): DexOpt: --- BEGIN 'MIDI_Output.apk' (bootstrap=0) ---
  D/dalvikvm( 5320): DexOpt: load 50ms, verify+opt 174ms, 1050124 bytes
  D/dalvikvm( 5251): DexOpt: --- END 'MIDI_Output.apk' (success) ---
  D/dalvikvm( 5251): DEX prep '/storage/emulated/legacy/Data/d/MIDI_Output.apk': u
  nzip in 14ms, rewrite 401ms
  W/dalvikvm( 5251): dvmFindClassByName rejecting 'org.drivers.midioutput/MIDI_Out
  put'
  D/midi    ( 5251): >> Before initializing MIDI driver version 1
  W/dalvikvm( 5251): Exception Ljava/lang/UnsatisfiedLinkError; thrown while initi
  alizing Lorg/drivers/midioutput/MidiDriver;

  W/System.err( 5251): java.lang.UnsatisfiedLinkError: Couldn't load midi from loa
  der dalvik.system.DexClassLoader[DexPathList[[zip file "/storage/sdcard0/Data/d/
  MIDI_Output.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]]: findLib
  rary returned null

  W/System.err( 5251):    at java.lang.Runtime.loadLibrary(Runtime.java:358)
  W/System.err( 5251):    at java.lang.System.loadLibrary(System.java:526)
  W/System.err( 5251):    at org.drivers.midioutput.MidiDriver.<clinit>(MidiDriver
  .java:177)
  W/System.err( 5251):    at org.drivers.midioutput.MIDI_Output.<init>(MIDI_Output
  .java:22)
  W/System.err( 5251):    at java.lang.Class.newInstanceImpl(Native Method)
  W/System.err( 5251):    at java.lang.Class.newInstance(Class.java:1208)
  W/System.err( 5251):    at dalvik.system.NativeStart.run(Native Method)
  D/dalvikvm( 5251): GC_FOR_ALLOC freed 795K, 9% free 9091K/9920K, paused 13ms,
  total 13ms
  D/dalvikvm( 5251): GC_CONCURRENT freed 9K, 4% free 9532K/9920K, paused
  2ms+2ms, total 22ms

我了解无法找到该库.麻烦的是，我不知道在哪里搜索这个库.错误消息提到 /vendor/lib 和 /system/lib.我将 libmidi.so 添加到这些库中.我将库添加到应用程序目录 com.embarcadero.MIDI_Output_Project/lib (这是 android 存储库的位置)，到 /storage/sdcard0/Data/d/ (存储包含 Java 类的 MIDI_Output.apk 的目录).我从字面上用 libmidi.so 洒在我的 android 系统上.我也尝试加载 libmidi.so.

I understand that the library cannot be found. Trouble is, I do not know where this library is searched. The error message mentions /vendor/lib and /system/lib. I added libmidi.so to these libraries. I added the library to the application directory com.embarcadero.MIDI_Output_Project/lib (that is where android stores the library), to /storage/sdcard0/Data/d/ (the directory where MIDI_Output.apk containing the Java classes are stored). I literally sprinkled my android system with libmidi.so. I have tried to load libmidi.so as well.

作为测试，我在 MIDI_Output 包中添加了一个非常简单的示例类并调用了函数 test_int.这运行没有任何问题.

As a test I added a very simple example class to the MIDI_Output package and called function test_int. This runs without any problems.

  package org.drivers.midioutput;

  import android.util.Log;

  public class class_test
  {
     public int test_int (int n)
     {
        int sq = n * n;
        String mess = "*** test_int computes " + String.valueOf (sq);

        Log.d ("midi", mess);
        return n * n;
     }
  }

我的问题是:DalvikVM 在哪个目录中寻找上述设置中的本机库(Delphi 通过 JNI 调用 Java 类，Java 通过 NDK 调用 C 库)?

My question is: in which directory is DalvikVM looking for native library in a setup described above (Delphi calling a Java class via JNI and Java calling a C library via NDK)?

第二个问题:这完全是库搜索路径问题吗?也许 Delphi 无法通过 JNI 调用 NDK.

A second question: is it a library search path problem at all? Maybe Delphi is not able to call NDK via JNI.

我尽量做到简短.如果有人认为我应该添加更多代码，请告诉我.非常感谢任何帮助.

I have tried to be as brief as possible. If anyone thinks I should add more code just let me know. Any help is greatly appreciated.

推荐答案

Delphi使用的NDK库应该放在android-ndk-r8eplatformsandroid-14arch-armusrlib.我意识到这要感谢 Arioch 和 Chris 直接使用 NDK 的建议.Source tlandroid 目录中的大多数android 文件都包含文件Androidapi.inc，其中包含以下定义

NDK libraries that are used by Delphi should be placed in <path to your PlatformSDKs>android-ndk-r8eplatformsandroid-14arch-armusrlib. I realised this thanks the recommendations of Arioch and Chris to use the NDK directly. Most android files in the Source tlandroid directory include the file Androidapi.inc which contains the following definitions

const
    AndroidLib            = '/usr/lib/libandroid.so';
    AndroidJniGraphicsLib = '/usr/lib/libjnigraphics.so';
    AndroidEglLib         = '/usr/lib/libEGL.so';
    AndroidGlesLib        = '/usr/lib/libGLESv1_CM.so';
    AndroidGles2Lib       = '/usr/lib/libGLESv2.so';
    AndroidLogLib         = '/usr/lib/liblog.so';
    AndroidOpenSlesLib    = '/usr/lib/libOpenSLES.so';

目录 /usr/lib 在 Nexus-7 上不存在，但我在上面提到的路径中找到了它，所有文件都在 const 部分中声明.将 libmidi.so 复制到此目录即可解决问题.我现在有一个不小的问题，就是听不到声音.我现在会尝试解决这个问题，并尝试直接调用 NDK.

The directory /usr/lib does not exist on the Nexus-7 but I found it in the path mentioned above with all the files declared in the const part. Copying the libmidi.so to this directory solved the problem. I now have the not so minor problem of hearing no sound. I'll try to solve that now, as well as trying to call the NDK directly.

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