异常捕获

package Dao;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 java.io.File;import java.io.FileOutputStream;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.Map;public class CrashHandler implements Thread.UncaughtExceptionHandler {    public static final String TAG = "CrashHandler";    private Thread.UncaughtExceptionHandler mDefaultHandler;    private static CrashHandler INSTANCE = new CrashHandler();    private Context mContext;    private Map<String, String> infos = new HashMap<String, String>();    private DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");    private CrashHandler() {    }    public static CrashHandler getInstance() {        return INSTANCE;    }    public void init(Context context) {        mContext = context;        mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler();        Thread.setDefaultUncaughtExceptionHandler(this);    }    @Override    public void uncaughtException(Thread thread, Throwable ex) {        if (!handleException(ex) && mDefaultHandler != null) {            mDefaultHandler.uncaughtException(thread, ex);        } else {            try {                Thread.sleep(3000);            } catch (InterruptedException e) {                Log.e(TAG, "错误日志 : ", e);            }            System.exit(1);        }    }    private boolean handleException(Throwable ex) {        if (ex == null) {            return false;        }        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();        collectDeviceInfo(mContext);        saveCrashInfo2File(ex);        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(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 = "/mnt/sdcard/";                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;    }}