安卓程序运行中突然崩溃的时候打印日志到本地

转载自：http://blog.sina.com.cn/s/blog_6a528c550102vc1a.html Yocn博客

我们在开发android应用的时候经常有这样一个情景：程序用着用着在某个地方崩溃了，每次的情况都不尽相同，这时候我们没有在电脑旁边，有电脑的时候去看代码的时候总是觉着哪儿都不可能出错。这时候我们就想如果我们能得到异常退出时候的log信息就好了。
这时候下面这一段代码就可能相当有用了：

package com.test.application;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.Writer;
import java.lang.Thread.UncaughtExceptionHandler;
import java.lang.reflect.Field;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.os.Build;
import android.os.Environment;
import android.os.Looper;
import android.util.Log;
import android.widget.Toast;

import com.duole.fm.utils.Constants;

public class CrashHandler implements UncaughtExceptionHandler {

// 系统默认的UncaughtException处理类
private Thread.UncaughtExceptionHandler mDefaultHandler;
// CrashHandler实例
private static CrashHandler instance;
// 程序的Context对象
private Context mContext;
// 用来存储设备信息和异常信息
private Map infos = new HashMap();

// 用于格式化日期,作为日志文件名的一部分
private DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");


private CrashHandler() {
}


public static CrashHandler getInstance() {
    if (instance == null)
        instance = new CrashHandler();
    return instance;
}


public void init(Context context) {
    mContext = context;
    Log.e(Constants.TAG, "error : ");
    // 获取系统默认的UncaughtException处理器
    mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler();
    // 设置该CrashHandler为程序的默认处理器
    Thread.setDefaultUncaughtExceptionHandler(this);
}


@Override
public void uncaughtException(Thread thread, Throwable ex) {
    if (!handleException(ex) && mDefaultHandler != null) {
        // 如果用户没有处理则让系统默认的异常处理器来处理
        mDefaultHandler.uncaughtException(thread, ex);
    } else {
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            Log.e(Constants.TAG, "error : ", e);
        }
        // 退出程序
        android.os.Process.killProcess(android.os.Process.myPid());
        System.exit(1);
    }
}


private boolean handleException(Throwable ex) {
    if (ex == null) {
        return false;
    }
    // 收集设备参数信息
    collectDeviceInfo(mContext);

    // 使用Toast来显示异常信息
    new Thread() {
        @Override
        public void run() {
            Looper.prepare();
            Toast.makeText(mContext, "很抱歉,程序出现异常,即将退出.", Toast.LENGTH_SHORT).show();
            Looper.loop();
        }
    }.start();
    // 保存日志文件
    try {
        saveCatchInfo2File(ex);
    } catch (Exception e) {
        e.printStackTrace();
    }
    return true;
}


public void collectDeviceInfo(Context ctx) {
    try {
        PackageManager pm = ctx.getPackageManager();
        PackageInfo pi = pm.getPackageInfo(ctx.getPackageName(), PackageManager.GET_ACTIVITIES);
        if (pi != null) {
            String versionName = pi.versionName == null ? "null" : pi.versionName;
            String versionCode = pi.versionCode + "";
            infos.put("versionName", versionName);
            infos.put("versionCode", versionCode);
        }
    } catch (NameNotFoundException e) {
        Log.e(Constants.TAG, "an error occured when collect package info", e);
    }
    Field[] fields = Build.class.getDeclaredFields();
    for (Field field : fields) {
        try {
            field.setAccessible(true);
            infos.put(field.getName(), field.get(null).toString());
            Log.d(Constants.TAG, field.getName() + " : " + field.get(null));
        } catch (Exception e) {
            Log.e(Constants.TAG, "an error occured when collect crash info", e);
        }
    }
}


private String saveCatchInfo2File(Throwable ex) {

    StringBuffer sb = new StringBuffer();
    for (Map.Entry entry : infos.entrySet()) {
        String key = entry.getKey();
        String value = entry.getValue();
        sb.append(key + "=" + value + "\n");
    }

    Writer writer = new StringWriter();
    PrintWriter printWriter = new PrintWriter(writer);
    ex.printStackTrace(printWriter);
    Throwable cause = ex.getCause();
    while (cause != null) {
        cause.printStackTrace(printWriter);
        cause = cause.getCause();
    }
    printWriter.close();
    String result = writer.toString();
    sb.append(result);
    try {
        long timestamp = System.currentTimeMillis();
        String time = formatter.format(new Date());
        String fileName = "crash-" + time + "-" + timestamp + ".log";
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            String path = Constants.SDPATH + "/crash/";
            File dir = new File(path);
            if (!dir.exists()) {
                dir.mkdirs();
            }
            FileOutputStream fos = new FileOutputStream(path + fileName);
            fos.write(sb.toString().getBytes());
            // 发送给开发人员
            sendCrashLog2PM(path + fileName);
            fos.close();
        }
        return fileName;
    } catch (Exception e) {
        Log.e(Constants.TAG, "an error occured while writing file...", e);
    }
    return null;
}


private void sendCrashLog2PM(String fileName) {
    if (!new File(fileName).exists()) {
        Toast.makeText(mContext, "日志文件不存在！", Toast.LENGTH_SHORT).show();
        return;
    }
    FileInputStream fis = null;
    BufferedReader reader = null;
    String s = null;
    try {
        fis = new FileInputStream(fileName);
        reader = new BufferedReader(new InputStreamReader(fis, "GBK"));
        while (true) {
            s = reader.readLine();
            if (s == null)
                break;
            // 由于目前尚未确定以何种方式发送，所以先打出log日志。
            Log.i("info", s.toString());
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } finally { // 关闭流
        try {
            reader.close();
            fis.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

}

在Application里面加上下面这句：
CrashHandler catchHandler = CrashHandler.getInstance();
catchHandler.init(getApplicationContext());

这样就可以随时得到crash时候的log信息了