在本地复制和解决Android java.lang.unsatisfiedLinkError [英] Reproducing and resolving Android java.lang.unsatisfiedLinkError locally
问题描述
我和一个朋友一起创建了一个Android应用来组织学校成绩.该应用程序可以在我的设备和大多数用户设备上正常运行，但是崩溃率超过3％，这主要是由于java.lang.UnsatisfiedLinkError并在Android 7.0、8.1和9版本上发生的.
Together with a friend I have created an Android app to organize school grades. The app works fine on my device and on most user devices, however there is a crashing rate over 3 percent, mostly because of java.lang.UnsatisfiedLinkError and occurring on Android versions 7.0, 8.1 as well as 9.
我已经在手机和包括所有架构在内的多个仿真器上测试了该应用程序.我将应用程序作为android-app-bundle上载到应用程序商店，并怀疑这可能是问题的根源.
I've tested the app on my phone and on several emulators, including all the architectures. I upload the app to the app store as an android-app-bundle and suspect that this could be the source of the problem.
我在这里有点迷茫，因为我已经尝试了好几件事，但是到目前为止，我既不能减少出现的次数，也无法在任何设备上重现它.任何帮助将不胜感激.
I am a bit lost here, because I've tried already several things but so far I was not able to either reduce the number of occurrences nor to reproduce it on any of my devices. Any help will be highly appreciated.
我找到了此资源指出Android有时无法解压缩外部库.因此，他们创建了 ReLinker库，该库将尝试从压缩的应用程序中获取库:
I have found this resource which points out that Android sometimes fails to unpack external libraries. Therefore they created a ReLinker library which will try to fetch the libraries from the compressed app:
不幸的是，这并没有减少由于java.lang.UnsatisfiedLinkError而导致的崩溃数量.我继续进行在线研究，发现本文，这表明问题出在64位库中.因此，我删除了64位库(该应用程序仍可在所有设备上运行，因为64位架构也可以执行32位库).但是，该错误仍然会像以前一样以相同的频率发生.
Unfortunately, this did not reduce the amount of crashes due to java.lang.UnsatisfiedLinkError. I continued my online research and found this article, which suggests that the problem lies in the 64-bit libraries. So I removed the 64bit libraries (the app still runs on all devices, because 64-bit architectures can also execute 32-bit libraries). However, the error still occurs in the same frequency like before.
通过google-play-console，我得到了以下崩溃报告:
Through the google-play-console I got the following crash report:
java.lang.UnsatisfiedLinkError:
at ch.fidelisfactory.pluspoints.Core.Wrapper.callCoreEndpointJNI (Wrapper.java)
at ch.fidelisfactory.pluspoints.Core.Wrapper.a (Wrapper.java:9)
at ch.fidelisfactory.pluspoints.Model.Exam.a (Exam.java:46)
at ch.fidelisfactory.pluspoints.SubjectActivity.i (SubjectActivity.java:9)
at ch.fidelisfactory.pluspoints.SubjectActivity.onCreate (SubjectActivity.java:213)
at android.app.Activity.performCreate (Activity.java:7136)
at android.app.Activity.performCreate (Activity.java:7127)
at android.app.Instrumentation.callActivityOnCreate (Instrumentation.java:1272)
at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2908)
at android.app.ActivityThread.handleLaunchActivity (ActivityThread.java:3063)
at android.app.servertransaction.LaunchActivityItem.execute (LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks (TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute (TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage (ActivityThread.java:1823)
at android.os.Handler.dispatchMessage (Handler.java:107)
at android.os.Looper.loop (Looper.java:198)
at android.app.ActivityThread.main (ActivityThread.java:6729)
at java.lang.reflect.Method.invoke (Method.java)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:876)
Wrapper.java是调用我们的本机库的类.它指向的行如下所示:
The Wrapper.java is the class which calls our native library. The line it points to however just reads as follows:
import java.util.HashMap;
ch.fidelisfactory.pluspoints.Core.Wrapper.callCoreEndpointJNI是本机cpp库的入口点.
The ch.fidelisfactory.pluspoints.Core.Wrapper.callCoreEndpointJNI is the entry point to our native cpp library.
在本地cpp库中，我们使用一些外部库(curl，jsoncpp，plog-logging，sqlite和tinyxml2).
In the native cpp library we use some external libraries (curl, jsoncpp, plog-logging, sqlite and tinyxml2).
编辑2019年6月4日
根据要求，此处为Wrapper.java的代码:
As requested, here the code of Wrapper.java:
package ch.fidelisfactory.pluspoints.Core;
import android.content.Context;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.Serializable;
import java.util.HashMap;
import ch.fidelisfactory.pluspoints.Logging.Log;
/***
* Wrapper around the cpp pluspoints core
*/
public class Wrapper {
/**
* An AsyncCallback can be given to the executeEndpointAsync method.
* The callback method will be called with the returned json from the core.
*/
public interface AsyncCallback {
void callback(JSONObject object);
}
public static boolean setup(Context context) {
String path = context.getFilesDir().getPath();
return setupWithFolderAndLogfile(path,
path + "/output.log");
}
private static boolean setupWithFolderAndLogfile(String folderPath, String logfilePath) {
HashMap<String, Serializable> data = new HashMap<>();
data.put("folder", folderPath);
data.put("logfile", logfilePath);
JSONObject res = executeEndpoint("/initialization", data);
return !isErrorResponse(res);
}
public static JSONObject executeEndpoint(String path, HashMap<String, Serializable> data) {
JSONObject jsonData = new JSONObject(data);
String res = callCoreEndpointJNI(path, jsonData.toString());
JSONObject ret;
try {
ret = new JSONObject(res);
} catch (JSONException e) {
Log.e("Error while converting core return statement to json.");
Log.e(e.getMessage());
Log.e(e.toString());
ret = new JSONObject();
try {
ret.put("error", e.toString());
} catch (JSONException e2) {
Log.e("Error while putting the error into the return json.");
Log.e(e2.getMessage());
Log.e(e2.toString());
}
}
return ret;
}
public static void executeEndpointAsync(String path, HashMap<String, Serializable> data, AsyncCallback callback) {
// Create and start the task.
AsyncCoreTask task = new AsyncCoreTask();
task.setCallback(callback);
task.setPath(path);
task.setData(data);
task.execute();
}
public static boolean isErrorResponse(JSONObject data) {
return data.has("error");
}
public static boolean isSuccess(JSONObject data) {
String res;
try {
res = data.getString("status");
} catch (JSONException e) {
Log.w(String.format("JsonData is no status message: %s", data.toString()));
res = "no";
}
return res.equals("success");
}
public static Error errorFromResponse(JSONObject data) {
String errorDescr;
if (isErrorResponse(data)) {
try {
errorDescr = data.getString("error");
} catch (JSONException e) {
errorDescr = e.getMessage();
errorDescr = "There was an error while getting the error message: " + errorDescr;
}
} else {
errorDescr = "Data contains no error message.";
}
return new Error(errorDescr);
}
private static native String callCoreEndpointJNI(String jPath, String jData);
/**
* Log a message to the core
* @param level The level of the message. A number from 0 (DEBUG) to 5 (FATAL)
* @param message The message to log
*/
public static native void log(int level, String message);
}
此外，这里是入口点的cpp定义，该入口然后调用我们的核心库:
Additionally,here the cpp definition of the entrypoint that then calls our core library:
#include <jni.h>
#include <string>
#include "pluspoints.h"
extern "C"
JNIEXPORT jstring JNICALL
Java_ch_fidelisfactory_pluspoints_Core_Wrapper_callCoreEndpointJNI(
JNIEnv* env,
jobject /* this */,
jstring jPath,
jstring jData) {
const jsize pathLen = env->GetStringUTFLength(jPath);
const char* pathChars = env->GetStringUTFChars(jPath, (jboolean *)0);
const jsize dataLen = env->GetStringUTFLength(jData);
const char* dataChars = env->GetStringUTFChars(jData, (jboolean *)0);
std::string path(pathChars, (unsigned long) pathLen);
std::string data(dataChars, (unsigned long) dataLen);
std::string result = pluspoints_execute(path.c_str(), data.c_str());
env->ReleaseStringUTFChars(jPath, pathChars);
env->ReleaseStringUTFChars(jData, dataChars);
return env->NewStringUTF(result.c_str());
}
extern "C"
JNIEXPORT void JNICALL Java_ch_fidelisfactory_pluspoints_Core_Wrapper_log(
JNIEnv* env,
jobject,
jint level,
jstring message) {
const jsize messageLen = env->GetStringUTFLength(message);
const char *messageChars = env->GetStringUTFChars(message, (jboolean *)0);
std::string cppMessage(messageChars, (unsigned long) messageLen);
pluspoints_log((PlusPointsLogLevel)level, cppMessage);
}
这是pluspoints.h文件:
Here, the pluspoints.h file:
/**
* Copyright 2017 FidelisFactory
*/
#ifndef PLUSPOINTSCORE_PLUSPOINTS_H
#define PLUSPOINTSCORE_PLUSPOINTS_H
#include <string>
/**
* Send a request to the Pluspoints core.
* @param path The endpoint you wish to call.
* @param request The request.
* @return The return value from the executed endpoint.
*/
std::string pluspoints_execute(std::string path, std::string request);
/**
* The different log levels at which can be logged.
*/
typedef enum {
LEVEL_VERBOSE = 0,
LEVEL_DEBUG = 1,
LEVEL_INFO = 2,
LEVEL_WARNING = 3,
LEVEL_ERROR = 4,
LEVEL_FATAL = 5
} PlusPointsLogLevel;
/**
* Log a message with the info level to the core.
*
* The message will be written in the log file in the core.
* @note The core needs to be initialized before this method can be used.
* @param level The level at which to log the message.
* @param logMessage The log message
*/
void pluspoints_log(PlusPointsLogLevel level, std::string logMessage);
#endif //PLUSPOINTSCORE_PLUSPOINTS_H
推荐答案
UnsatisfiedLinkError发生在您的代码由于某种原因而试图调用不存在的smth时:
UnsatisfiedLinkError happens when your code tries to call smth that doesn't exist for some reason: post about it
这是使用Multidex应用程序的潜在原因之一:
Here is one of potential reasons for multidex apps:
如今，几乎每个Android应用程序都使用Multidex来包含更多内容.在构建DEX文件时，构建工具会尝试了解开始时需要哪些类，然后将其放入主要索引.但是，它们可能会遗漏smth，尤其是在绑定JNI时.
Nowadays almost every Android app uses Multidex to be able to include more stuff in it. When building the DEX file, build tools try to understand which classes are required on the start and puts them to the main dex. However, they can miss smth, especially when JNI is bound.
You can try manually marking the Wrapper class as required to be in the main DEX: docs. It may help it to bring its dependent native library as well in case if you have a multidex app.
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