Android系統的“程式異常退出”，給應用的使用者體驗造成不良影響。為了捕獲應用執行時異常並給出友好提示，便可繼承UncaughtExceptionHandler類來處理。

思路：

        1.此類主要完成一下幾個任務

        1.1 提示友好的錯誤資訊

        1.1.1網路異常，錯誤碼：%d

        1.1.2網路異常，請求超時

        1.1.3網路異常，讀取資料超時

        1.1.4網路連線失敗，請檢查網路設定

        1.1.5資料解析異常

        1.1.6資料解析異常

        1.1.7檔案流異常

        1.1.8應用程式執行時異常

        1.2 儲存異常日誌

        1.2.1判斷是否掛載了SD卡

        1.2.2沒有掛載SD卡，無法寫檔案，直接return

        1.2.3將異常寫入檔案

1.3 自定義異常處理:收集錯誤資訊&傳送錯誤報告

        現在來研究一下 開源中國 異常處理框架。

/**
 * 應用程式異常類：用於捕獲異常和提示錯誤資訊
 * @author liux (http://my.oschina.net/liux)
 * @version 1.0
 * @created 2012-3-21
 */
public class AppException extends Exception implements UncaughtExceptionHandler{

	private final static boolean Debug = false;//是否儲存錯誤日誌
	
	/** 定義異常型別 */
	public final static byte TYPE_NETWORK 	= 0x01;
	public final static byte TYPE_SOCKET	= 0x02;
	public final static byte TYPE_HTTP_CODE	= 0x03;
	public final static byte TYPE_HTTP_ERROR= 0x04;
	public final static byte TYPE_XML	 	= 0x05;
	public final static byte TYPE_IO	 	= 0x06;
	public final static byte TYPE_RUN	 	= 0x07;
	public final static byte TYPE_JSON	 	= 0x08;
	
	private byte type;
	private int code;
	
	/** 系統預設的UncaughtException處理類 */
	private Thread.UncaughtExceptionHandler mDefaultHandler;
	
	private AppException(){
		this.mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler();
	}
	
	private AppException(byte type, int code, Exception excp) {
		super(excp);
		this.type = type;
		this.code = code;		
		if(Debug){
			this.saveErrorLog(excp);
		}
	}
	public int getCode() {
		return this.code;
	}
	public int getType() {
		return this.type;
	}
	
	/**
	 * 提示友好的錯誤資訊
	 * @param ctx
	 */
	public void makeToast(Context ctx){
		switch(this.getType()){
		case TYPE_HTTP_CODE:
			String err = ctx.getString(R.string.http_status_code_error, this.getCode());
			Toast.makeText(ctx, err, Toast.LENGTH_SHORT).show();
			break;
		case TYPE_HTTP_ERROR:
			Toast.makeText(ctx, R.string.http_exception_error, Toast.LENGTH_SHORT).show();
			break;
		case TYPE_SOCKET:
			Toast.makeText(ctx, R.string.socket_exception_error, Toast.LENGTH_SHORT).show();
			break;
		case TYPE_NETWORK:
			Toast.makeText(ctx, R.string.network_not_connected, Toast.LENGTH_SHORT).show();
			break;
		case TYPE_XML:
			Toast.makeText(ctx, R.string.xml_parser_failed, Toast.LENGTH_SHORT).show();
			break;
		case TYPE_JSON:
			Toast.makeText(ctx, R.string.xml_parser_failed, Toast.LENGTH_SHORT).show();
			break;
		case TYPE_IO:
			Toast.makeText(ctx, R.string.io_exception_error, Toast.LENGTH_SHORT).show();
			break;
		case TYPE_RUN:
			Toast.makeText(ctx, R.string.app_run_code_error, Toast.LENGTH_SHORT).show();
			break;
		}
	}
	
	/**
	 * 儲存異常日誌
	 * @param excp
	 */
	public void saveErrorLog(Exception excp) {
		String errorlog = "errorlog.txt";
		String savePath = "";
		String logFilePath = "";
		FileWriter fw = null;
		PrintWriter pw = null;
		try {
			//判斷是否掛載了SD卡
			String storageState = Environment.getExternalStorageState();		
			if(storageState.equals(Environment.MEDIA_MOUNTED)){
				savePath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/OSChina/Log/";
				File file = new File(savePath);
				if(!file.exists()){
					file.mkdirs();
				}
				logFilePath = savePath + errorlog;
			}
			//沒有掛載SD卡，無法寫檔案
			if(logFilePath == ""){
				return;
			}
			File logFile = new File(logFilePath);
			if (!logFile.exists()) {
				logFile.createNewFile();
			}
			fw = new FileWriter(logFile,true);
			pw = new PrintWriter(fw);
			pw.println("--------------------"+(new Date().toLocaleString())+"---------------------");	
			excp.printStackTrace(pw);
			pw.close();
			fw.close();
		} catch (Exception e) {
			e.printStackTrace();		
		}finally{ 
			if(pw != null){ pw.close(); } 
			if(fw != null){ try { fw.close(); } catch (IOException e) { }}
		}

	}
	
	public static AppException http(int code) {
		return new AppException(TYPE_HTTP_CODE, code, null);
	}
	
	public static AppException http(Exception e) {
		return new AppException(TYPE_HTTP_ERROR, 0 ,e);
	}

	public static AppException socket(Exception e) {
		return new AppException(TYPE_SOCKET, 0 ,e);
	}
	
	public static AppException io(Exception e) {
		if(e instanceof UnknownHostException || e instanceof ConnectException){
			return new AppException(TYPE_NETWORK, 0, e);
		}
		else if(e instanceof IOException){
			return new AppException(TYPE_IO, 0 ,e);
		}
		return run(e);
	}
	
	public static AppException xml(Exception e) {
		return new AppException(TYPE_XML, 0, e);
	}
	
	public static AppException json(Exception e) {
		return new AppException(TYPE_JSON, 0, e);
	}
	
	public static AppException network(Exception e) {
		if(e instanceof UnknownHostException || e instanceof ConnectException){
			return new AppException(TYPE_NETWORK, 0, e);
		}
		else if(e instanceof HttpException){
			return http(e);
		}
		else if(e instanceof SocketException){
			return socket(e);
		}
		return http(e);
	}
	
	public static AppException run(Exception e) {
		return new AppException(TYPE_RUN, 0, e);
	}

	/**
	 * 獲取APP異常崩潰處理物件
	 * @param context
	 * @return
	 */
	public static AppException getAppExceptionHandler(){
		return new AppException();
	}
	
	@Override
	public void uncaughtException(Thread thread, Throwable ex) {

		if(!handleException(ex) && mDefaultHandler != null) {
			mDefaultHandler.uncaughtException(thread, ex);
		}

	}
	/**
	 * 自定義異常處理:收集錯誤資訊&傳送錯誤報告
	 * @param ex
	 * @return true:處理了該異常資訊;否則返回false
	 */
	private boolean handleException(Throwable ex) {
		if(ex == null) {
			return false;
		}
		
		final Context context = AppManager.getAppManager().currentActivity();
		
		if(context == null) {
			return false;
		}
		
		final String crashReport = getCrashReport(context, ex);
		//顯示異常資訊&傳送報告
		new Thread() {
			public void run() {
				Looper.prepare();
				UIHelper.sendAppCrashReport(context, crashReport);
				Looper.loop();
			}

		}.start();
		return true;
	}
	/**
	 * 獲取APP崩潰異常報告
	 * @param ex
	 * @return
	 */
	private String getCrashReport(Context context, Throwable ex) {
		PackageInfo pinfo = ((AppContext)context.getApplicationContext()).getPackageInfo();
		StringBuffer exceptionStr = new StringBuffer();
		exceptionStr.append("Version: "+pinfo.versionName+"("+pinfo.versionCode+")\n");
		exceptionStr.append("Android: "+android.os.Build.VERSION.RELEASE+"("+android.os.Build.MODEL+")\n");
		exceptionStr.append("Exception: "+ex.getMessage()+"\n");
		StackTraceElement[] elements = ex.getStackTrace();
		for (int i = 0; i < elements.length; i++) {
			exceptionStr.append(elements[i].toString()+"\n");
		}
		return exceptionStr.toString();
	}
}
 

1.在Application子類，註冊App異常崩潰處理器。

  application是用來儲存全域性變數的，並且是在package建立的時候就跟著存在了。

  Thread.setDefaultUncaughtExceptionHandler()方法將異常處理類設定到執行緒上。

	@Override
	public void onCreate() {
		super.onCreate();
        Thread.setDefaultUncaughtExceptionHandler(AppException.getAppExceptionHandler());

	}

	/**
	 * 檢查版本更新
	 * @param url
	 * @return
	 */
	public static Update checkVersion(AppContext appContext) throws AppException {
		try{
			return Update.parse(http_get(appContext, URLs.UPDATE_VERSION));		
		}catch(Exception e){
			if(e instanceof AppException)
				throw (AppException)e;
			throw AppException.network(e);
		}
	}
 

public static Update parse(InputStream inputStream) throws IOException, AppException {
		Update update = null;

        try {        	
      		//.......
        } catch (XmlPullParserException e) {
			throw AppException.xml(e);
        } finally {
        	inputStream.close();	
        }      
        return update;       
}

UpdateManager.java

new Thread(){
			public void run() {
				Message msg = new Message();
				try {					
					Update update = ApiClient.checkVersion((AppContext)mContext.getApplicationContext());
					msg.what = 1;
					msg.obj = update;
				} catch (AppException e) {
					e.printStackTrace();
				}
				handler.sendMessage(msg);
			}			
		}.start();	

    /**
     * 下載圖片-可指定顯示圖片的高寬
     * @param url
     * @param width
     * @param height
     */
    private Bitmap downloadBitmap(String url, int width, int height) {   
        Bitmap bitmap = null;
        try {
			//http載入圖片
			bitmap = ApiClient.getNetBitmap(url);
			if(width > 0 && height > 0) {
				//指定顯示圖片的高寬
				bitmap = Bitmap.createScaledBitmap(bitmap, width, height, true);
			} 
			//放入快取
			cache.put(url, new SoftReference<Bitmap>(bitmap));
		} catch (AppException e) {
			e.printStackTrace();
		}
        return bitmap;  
    }  

			final Handler handler = new Handler(){
				public void handleMessage(Message msg) {
					if(mProgress!=null)mProgress.dismiss();
					if(msg.what == 1){
						Result res = (Result)msg.obj;
						UIHelper.ToastMessage(QuestionPub.this, res.getErrorMessage());
						if(res.OK()){
							//傳送通知廣播
							if(res.getNotice() != null){
								UIHelper.sendBroadCast(QuestionPub.this, res.getNotice());
							}
							//清除之前儲存的編輯內容
							ac.removeProperty(AppConfig.TEMP_POST_TITLE,AppConfig.TEMP_POST_CATALOG,AppConfig.TEMP_POST_CONTENT);
							//跳轉到文章詳情
							finish();
						}
					}
					else {
						((AppException)msg.obj).makeToast(QuestionPub.this);
					}
				}
			};
			new Thread(){
				public void run() {
					Message msg = new Message();					
					try {
						Result res = ac.pubPost(post);
						msg.what = 1;
						msg.obj = res;
		            } catch (AppException e) {
		            	e.printStackTrace();
						msg.what = -1;
						msg.obj = e;
		            }
					handler.sendMessage(msg);
				}
			}.start();

msg.obj為Exception ，強制轉換到AppException，得到異常型別，Toast.

/**
	 * 傳送App異常崩潰報告
	 * 
	 * @param cont
	 * @param crashReport
	 */
	public static void sendAppCrashReport(final Context cont,
			final String crashReport) {
		AlertDialog.Builder builder = new AlertDialog.Builder(cont);
		builder.setIcon(android.R.drawable.ic_dialog_info);
		builder.setTitle(R.string.app_error);
		builder.setMessage(R.string.app_error_message);
		builder.setPositiveButton(R.string.submit_report,
				new DialogInterface.OnClickListener() {
					public void onClick(DialogInterface dialog, int which) {
						dialog.dismiss();
						// 傳送異常報告
						Intent i = new Intent(Intent.ACTION_SEND);
						// i.setType("text/plain"); //模擬器
						i.setType("message/rfc822"); // 真機
						i.putExtra(Intent.EXTRA_EMAIL,
								new String[] { "[email protected]" });
						i.putExtra(Intent.EXTRA_SUBJECT,
								"開源中國Android客戶端 - 錯誤報告");
						i.putExtra(Intent.EXTRA_TEXT, crashReport);
						cont.startActivity(Intent.createChooser(i, "傳送錯誤報告"));
						// 退出
						AppManager.getAppManager().AppExit(cont);
					}
				});
		builder.setNegativeButton(R.string.sure,
				new DialogInterface.OnClickListener() {
					public void onClick(DialogInterface dialog, int which) {
						dialog.dismiss();
						// 退出
						AppManager.getAppManager().AppExit(cont);
					}
				});
		builder.show();
	}