android 错误日志打印到本地

开发中测试遇到的bug到打印到本地，方便我们开发调试修改

1、创建MyCrashHandler类

package com.example.yu.myapplication;

import android.content.Context;
import android.os.Environment;
import android.util.Log;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.lang.Thread.UncaughtExceptionHandler;
import java.util.Date;


/**
 * 全局捕获导常，保存到本地错误日志。日志
 * 路径位于sdcard/错误日志Log/myErrorLog下。
 */
public class MyCrashHandler implements UncaughtExceptionHandler {


    private static MyCrashHandler instance;

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

    public void init(Context ctx) {
        Thread.setDefaultUncaughtExceptionHandler(this);
    }

    /**
     * 核心方法，当程序crash 会回调此方法， Throwable中存放这错误日志
     */
    @Override
    public void uncaughtException(Thread arg0, Throwable arg1) {

        String logPath;
        if (Environment.getExternalStorageState().equals(
                Environment.MEDIA_MOUNTED)) {
            logPath = Environment.getExternalStorageDirectory()
                    .getAbsolutePath()
                    + File.separator
                    + File.separator
                    + "错误日志Log";

            File file = new File(logPath);
            if (!file.exists()) {
                file.mkdirs();
            }
            try {
                FileWriter fw = new FileWriter(logPath + File.separator
                        + "myErrorlog.log", true);
                fw.write(new Date() + "错误原因：\n");
                // 错误信息
                // 这里还可以加上当前的系统版本，机型型号 等等信息
                StackTraceElement[] stackTrace = arg1.getStackTrace();
                fw.write(arg1.getMessage() + "\n");
                for (int i = 0; i < stackTrace.length; i++) {
                    fw.write("file:" + stackTrace[i].getFileName() + " class:"
                            + stackTrace[i].getClassName() + " method:"
                            + stackTrace[i].getMethodName() + " line:"
                            + stackTrace[i].getLineNumber() + "\n");
                }
                fw.write("\n");
                fw.close();
                // 上传错误信息到服务器
                // uploadToServer();
            } catch (IOException e) {
                Log.e("crash handler", "load file failed...", e.getCause());
            }
        }
        arg1.printStackTrace();
        android.os.Process.killProcess(android.os.Process.myPid());
    }
}

2、在Application中进行初始化

package com.example.yu.myapplication;

import android.app.Application;

/**
 * Created by yu on 2016/6/8.
 */
public class MyApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        //打开错误日志，保存到sd卡
        MyCrashHandler myCrashHandler = MyCrashHandler.getInstance();
        myCrashHandler.init(getApplicationContext());

    }
}

3、修改mainfests,添加权限，修改application节点

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.yu.myapplication">
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <application
        android:name=".MyApplication"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>