Android中处理异常——代码

1、

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="Crash.w.w"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:name=".CrashApplication" android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".MainActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>
    <uses-sdk android:minSdkVersion="8" />

 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> 
</manifest>

2、

package Crash.w.w;

import android.app.Activity;
import android.os.Bundle;

public class MainActivity extends Activity {
 private String s; 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        System.out.println(s.equals("any string")); 
    }
}

3、

package Crash.w.w;

import java.io.File; 
import java.io.FileOutputStream; 
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;

public class CrashHandler implements UncaughtExceptionHandler { 
     
    public static final String TAG = "CrashHandler"; 
     
    //系统默认的UncaughtException处理类   
    private Thread.UncaughtExceptionHandler mDefaultHandler; 
    //CrashHandler实例  
    private static CrashHandler INSTANCE = new CrashHandler(); 
    //程序的Context对象  
    private Context mContext; 
    //用来存储设备信息和异常信息  
    private Map<String, String> infos = new HashMap<String, String>(); 
 
    //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"); 
 
    /** 保证只有一个CrashHandler实例 */ 
    private CrashHandler() { 
    } 
 
    /** 获取CrashHandler实例 ,单例模式 */ 
    public static CrashHandler getInstance() { 
        return INSTANCE; 
    } 
 
    /**
     * 初始化
     * 
     * @param context
     */ 
    public void init(Context context) { 
        mContext = context; 
        //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); 
    } 
 
    /**
     * 当UncaughtException发生时会转入该函数来处理
     */ 
    @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(TAG, "error : ", e); 
            } 
            //退出程序  
            android.os.Process.killProcess(android.os.Process.myPid()); 
            System.exit(1); 
        } 
    } 
 
    /**
     * 自定义错误处理,收集错误信息 发送错误报告等操作均在此完成.
     * 
     * @param ex
     * @return true:如果处理了该异常信息;否则返回false.
     */ 
    private boolean handleException(Throwable ex) { 
        if (ex == null) { 
            return false; 
        } 
        //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_LONG).show(); 
                Looper.loop(); 
            } 
        }.start(); 
        //收集设备参数信息   
        collectDeviceInfo(mContext); 
        //保存日志文件   
        saveCrashInfo2File(ex); 
        return true; 
    } 
     
    /**
     * 收集设备参数信息
     * @param ctx
     */ 
    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(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(TAG, field.getName() + " : " + field.get(null)); 
            } catch (Exception e) { 
                Log.e(TAG, "an error occured when collect crash info", e); 
            } 
        } 
    } 
 
    /**
     * 保存错误信息到文件中
     * 
     * @param ex
     * @return  返回文件名称,便于将文件传送到服务器
     */ 
    private String saveCrashInfo2File(Throwable ex) { 
         
        StringBuffer sb = new StringBuffer(); 
        for (Map.Entry<String, String> 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 = "/sdcard/crash/"; 
               File dir = new File(path); 
                if (!dir.exists()) { 
                    dir.mkdirs(); 
                } 
                FileOutputStream fos = new FileOutputStream(path + fileName); 
                fos.write(sb.toString().getBytes()); 
                fos.close(); 
            } 
            return fileName; 
        } catch (Exception e) { 
            Log.e(TAG, "an error occured while writing file...", e); 
        } 
        return null; 
    } 
} 

4、

package Crash.w.w;

import android.app.Application;

public class CrashApplication extends Application { 
    @Override 
    public void onCreate() { 
        super.onCreate(); 
        CrashHandler crashHandler = CrashHandler.getInstance(); 
        crashHandler.init(getApplicationContext()); 
    } 
}