Android常用异常及解决方案

Android常用异常及解决方案

1、什么是异常?

      异常是指在程序运行中所出现的错误,这些错误会干扰到指令的正常执行,从而造成程序异常退出,这些异常出现的场景比如有:文件找不到,网络连接失败,非法参数等.

2、异常来源

      就Java语言来说,所有的异常都继承自Throwable

3、Android常见异常分类

1-编译时错误
(eg:ClassNotFoundException/layout中找不到ID等)
2-运行是错误
(eg:数组越界/类型转换异常等)

4、全局异常捕获

public class CrashHandler implements Thread.UncaughtExceptionHandler {

    private static CrashHandler mInstance;

    private Context mContext;

    private Thread.UncaughtExceptionHandler mDefaultHandler;

    //存储设备信息和异常信息
    private Map<String, String> mInfo = new HashMap<>();

    //文件日期格式
    private SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    private CrashHandler() {

    }

    /**
     * 单例模式
     *
     * @return
     */
    public static CrashHandler getmInstance() {
        if (mInstance == null) {
            synchronized (CrashHandler.class) {
                if (mInstance == null) {
                    mInstance = new CrashHandler();
                }
            }
        }
        return mInstance;
    }

    /**
     * 初始化
     *
     * @param context
     */
    public void init(Context context) {
        this.mContext = context.getApplicationContext();
        mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler();
        Thread.setDefaultUncaughtExceptionHandler(this);
    }

    @Override
    public void uncaughtException(Thread t, Throwable e) {
        Log.e("hpc", "错误信息");
        //1'收集错误信息
        //2'保存错误信息
        //3'上传服务器
        if (!handleException(e)) {
            //未处理,调用系统默认的处理器处理
            if (mDefaultHandler != null) {
                mDefaultHandler.uncaughtException(t, e);
            }
        } else {
            //已经人为处理
            Intent intent = new Intent(mContext.getApplicationContext(), MainActivity.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            PendingIntent restartIntent = PendingIntent.getActivity(
                    mContext.getApplicationContext(), 0, intent, 0);
            //退出程序
            AlarmManager mgr = (AlarmManager) mContext.getSystemService(Context.ALARM_SERVICE);
            mgr.set(AlarmManager.RTC, System.currentTimeMillis() + 1000,
                    restartIntent); // 1秒钟后重启应用*/
            android.os.Process.killProcess(android.os.Process.myPid());
        }
    }

    /**
     * 是否人为处理异常
     *
     * @return true已经处理 false未处理
     */
    private boolean handleException(Throwable e) {
        if (e == null) {
            return false;
        } else {
            //收集错误信息
            collectErrorInfo();
            //保存错误信息
            saveErrorInfo(e);
            return true;
        }
    }

    private void saveErrorInfo(Throwable e) {
        StringBuffer stringBuffer = new StringBuffer();
        for (Map.Entry<String, String> entry : mInfo.entrySet()) {
            String keyName = entry.getKey();
            String value = entry.getValue();
            stringBuffer.append(keyName + "=" + value + "\n");
        }

        StringWriter sw = new StringWriter();
        e.printStackTrace(new PrintWriter(sw, true));
        String strs = sw.toString();
        stringBuffer.append(strs);
        long curTime = System.currentTimeMillis();
        String time = dateFormat.format(new Date());
        String fileName = "crash-" + time + "-" + curTime + ".log";
        //判断有没有sd卡
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            String path = Environment.getExternalStorageDirectory() + File.separator;
            File dir = new File(path);
            if (!dir.exists()) {
                dir.mkdirs();
            }
            FileOutputStream fos = null;
            try {
                fos = new FileOutputStream(path + fileName);
                fos.write(stringBuffer.toString().getBytes());
            } catch (FileNotFoundException e1) {
                e1.printStackTrace();
            } catch (IOException e1) {
                e1.printStackTrace();
            } finally {
                try {
                    fos.close();
                    Log.e("hpc", dir.getAbsolutePath());
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
        }

    }

    private void collectErrorInfo() {
        PackageManager pm = mContext.getPackageManager();
        try {
            PackageInfo packageInfo = pm.getPackageInfo(mContext.getPackageName(), PackageManager.GET_ACTIVITIES);
            if (packageInfo != null) {
                String versionName = TextUtils.isEmpty(packageInfo.versionName) ? "未设置版本名称" : packageInfo.versionName;
                String versionCode = packageInfo.versionCode + "";
                mInfo.put("versionName", versionName);
                mInfo.put("versionCode", versionCode);

                Field fields[] = Build.class.getFields();
                if (fields != null && fields.length > 0) {
                    for (Field field : fields) {
                        field.setAccessible(true);
                        mInfo.put(field.getName(), field.get(null).toString());
                    }
                }

            }
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
    }
}

public class MainActivity extends AppCompatActivity {

    private String mStr;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    private void initContent() {
        System.out.println("" + (1 / 0));
    }

    public void error() {
        initContent();
    }
}

public class CustomApplication extends Application {

    private CrashHandler crashHandler;

    @Override
    public void onCreate() {
        super.onCreate();
        crashHandler = CrashHandler.getmInstance();
        crashHandler.init(this);
    }
}

5、最后推荐一个目前比较火的全局异常捕获库:Bugly