React Native release包全局错误处理——Android篇

可以看到，我们把AppErrorHandler组件作为整个页面组件的根组件使用。这样在release包中抛出JS异常时，我们就能到

/storage/emulated/0/Android/data/${packageName}/file/jsExceptionLogs/log_yyyy_MM_dd_HH_mm_ss.txt中拿到异常信息。

注：建议将app中生成的日志文件保存在/storage/emulated/0/Android/data/${packageName}/file/路径下，这个路径的内容会在APP被卸载时清除。与他同级的还有一个目录/storage/emulated/0/Android/data/${packageName}/caches，这个目录中往往用来存放一些应用缓存的临时内容，会在用户手动清除应用缓存时一并删除。上述的两个路径应该是属于Android外部存储的私有路径，我们往这里写入文件是不需要动态申请外部存储（EXTERNAL_STORAGE）写入权限的。 

2. 原生java异常

这类异常就比较严重了，一旦出现，APP会立即停止运行并闪退，造成极差的用户体验。为了捕获java中的全局未捕获异常，我们需要编写一个CrashHandler类并实现Thread.UncaughtExceptionHandler接口。代码比较简单，我就直接贴出整个类的实现吧：

CrashHandler.java

package com.smarthome;
import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Looper;
import android.util.Log;
import android.widget.Toast;
import androidx.annotation.NonNull;
import com.smarthome.utils.FileUtils;
import java.io.File;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.Writer;
import java.lang.reflect.Field;
import java.text.DateFORMat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

public class CrashHandler implements Thread.UncaughtExceptionHandler {
    private Context mContext;
    private static final String TAG = CrashHandler.class.getSimpleName();
    private CrashHandler() { }
    private static volatile CrashHandler instance;
    static CrashHandler getInstance() {
        if (instance == null) {
            synchronized (CrashHandler.class) {
                if (instance == null) {
                    instance = new CrashHandler();
                }
            }
        }
        return instance;
    }
    private Map crashInfos = new HashMap();  // 键值对的形式收集错误日志
    
    void init() {
        mContext = MainApplication.getAppContext();
        // 设置CrashHandler为程序默认的处理器
        Thread.setDefaultUncaughtExceptionHandler(this);
    }
    
    @Override
    public void uncaughtException(@NonNull Thread thread, @NonNull Throwable throwable) {
        handleException(throwable);
    }
    
    private void handleException(Throwable throwable) {
        getPackageInfo();
        String crashMsg = saveCrashInfo(throwable);
        writeLogToStorage(crashMsg);
        uploadCrashToServer(crashMsg);
        remindUserOfCrash();
    }
    
    private void getPackageInfo() {
        PackageManager packageManager = mContext.getPackageManager();
        try {
            PackageInfo packageInfo = packageManager.getPackageInfo(mContext.getPackageName(), PackageManager.GET_CONFIGURATIONS);
            if (packageInfo != null) {
                String packageName = packageInfo.packageName;
                String versionName = packageInfo.versionName;
                String versionCode;
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
                    versionCode = String.valueOf(packageInfo.getLongVersionCode());
                } else {
                    versionCode = String.valueOf(packageInfo.versionCode);
                }
                crashInfos.put("packageName", packageName);
                crashInfos.put("versionName", versionName);
                crashInfos.put("versionCode", versionCode);
            }
        } catch(PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        Field[] fields = Build.class.getDeclaredFields();
        for (Field field : fields) {
            try {
                field.setAccessible(true);
                crashInfos.put(field.getName(), String.valueOf(field.get(null)));
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
        }
    }
    
    private String saveCrashInfo(Throwable throwable) {
        StringBuilder sb = new StringBuilder();
        sb.append("Crash Log start: ==========================\n");
        for (Map.Entry entry : crashInfos.entrySet()) {
            String key = entry.geTKEy();
            String value = entry.getValue();
            sb.append(key).append(": ").append(value).append("\n");
        }
        Writer writer = new StringWriter();
        PrintWriter printWriter = new PrintWriter(writer);
        throwable.printStackTrace(printWriter);
        Throwable cause = throwable.getCause();
        // 回溯异常抛出链
        while (cause != null) {
            cause.printStackTrace(printWriter);
            cause = cause.getCause();
        }
        printWriter.close();
        String crashResult = writer.toString();
        sb.append("crashResult: ").append(crashResult);
        sb.append("end========================================\n");
        return sb.toString();
    }
    
    private void writeLogToStorage(String crashMsg) {
        String externalFilePath = FileUtils.getExternalFileDir().getPath();
        String targetDir = externalFilePath + File.separator + "crashlogs";
        File log = new File(targetDir);
        if (log.exists() ||
                (!log.exists() && log.mkdir())) {
            StringBuilder targetFilePath = new StringBuilder();
            Date now = new Date();
            DateFormat dateFormat = new SimpleDateFormat("yyyy_MM_dd_HH_mm_ss", Locale.getDefault());
            targetFilePath.append(targetDir).append(File.separator).append("crashlog_").append(dateFormat.format(now)).append(".txt");
            File targetFile = new File(targetFilePath.toString());
            FileUtils.writeTextToFiles(targetFile, crashMsg);
        }
    }
    
    private void uploadCrashToServer(String crashMsg) {
        Log.d(TAG, crashMsg);
    }
    
    private void remindUserOfCrash() {
        new Thread(() -> {
            Looper.prepare();
            Toast.makeText(mContext, "抱歉，程序发生异常，即将退出o(╥﹏╥)o", Toast.LENGTH_LONG).show();
            Looper.loop();
        }).start();
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        android.os.Process.killProcess(android.os.Process.myPid());
        System.exit(1);
    }
}