Android 读取SD卡中的text文件内容

public class MainActivity extends ActionBarActivity {
    private TextView mReadView;
    private String SDPATH =  Environment.getExternalStorageDirectory().getPath() ;
    private Handler mHandler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            String text = msg.obj.toString();
            mReadView.setText(text);

        }
    };


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mReadView = (TextView)this.findViewById(R.id.read_text);
        new Thread(new Runnable() {
            @Override
            public void run() {
                String text =  readSDFile("test.txt");
                Message message = new Message();
                message.obj = text;
                mHandler.sendMessage(message);
            }
        }).start();
    }

    public String readSDFile(String fileName) {
        StringBuffer sb = new StringBuffer();
        File file = new File(SDPATH + "//" + fileName);
        try {
            FileInputStream fis = new FileInputStream(file);
            int c;
            while ((c = fis.read()) != -1) {
                if(Character.isWhitespace(c) ){//判断是否是空格
                    continue;
                }
                sb.append((char) c);
            }
            fis.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        Pattern p = Pattern.compile("\\s*|\t|\r|\n");
        Matcher m = p.matcher(sb.toString());
        return  m.replaceAll("");
    }




}