把数据写入到文件或者读取文件内容
首先写读取和写入的两个方法
static public String ReadActivityFile(Context aContext, String aFile) {String buffer="";FileInputStream in2;try {in2 = aContext.openFileInput(aFile);InputStreamReader inReader = new InputStreamReader(in2);int buf= 1024;BufferedReader line = new BufferedReader(inReader,buf);String tmpBuffer = "";while ((tmpBuffer = line.readLine()) != null) {buffer += tmpBuffer;}line.close();inReader.close();in2.close();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}return buffer;}static public void WriteActivityFile(Context aContext, String aFile,String aBuffer) {try {FileOutputStream os = aContext.openFileOutput(aFile,Context.MODE_WORLD_READABLE + Context.MODE_WORLD_WRITEABLE);OutputStreamWriter outWriter = new OutputStreamWriter(os);outWriter.write(aBuffer, 0, aBuffer.length());outWriter.flush();outWriter.close();os.close();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}?然后在需要用的地方调用就行了，把需要的参数完成：
读取：
String buffer = "";buffer = FileUtils.ReadActivityFile(ScoreActivity.this,common.FAVORITE_DATA_FILE);
?写入：
FileUtils.WriteActivityFile(ScoreActivity.this,common.FAVORITE_DATA_FILE, buffer);
?
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下面的一个例子是：点击一次，把这条数据保存到文件里面，然后再点击一次，又取消保存，就是从文件删除：
LinearLayout ly = (LinearLayout) layout.findViewById(R.id.linear_score_choise);ly.setOnClickListener(new OnClickListener() {public void onClick(View arg0) {String buffer = "";buffer = FileUtils.ReadActivityFile(ScoreActivity.this,common.FAVORITE_DATA_FILE);boolean isFileBlank = false;if (buffer.length() <= 0) {// 如果buffer为空，则为true；isFileBlank = true;}boolean has_fav = false;// 如果buffer不为空if (!isFileBlank) {// 解析到集合中Vector fav_list = CommonUtil.Split(buffer, ",");buffer = "";// buffer初始化for (int i = 0; i < fav_list.size(); i++) {String fav_id = (String) fav_list.elementAt(i);// System.out.println(fav_id);if (fav_id.equals(mId)) {has_fav = true;continue;}if (fav_id.length() <= 0) {continue;}buffer += fav_id;if (i != fav_list.size() - 1) {buffer += ",";}}}if (buffer.length() > 0&& buffer.charAt(buffer.length() - 1) == ',') {buffer = buffer.substring(0, buffer.length() - 1);}if (has_fav) {// 取消关注imageView.setImageResource(R.drawable.gray_star);Toast.makeText(ScoreActivity.this, "该场关注已取消！",Toast.LENGTH_SHORT).show();FileUtils.WriteActivityFile(ScoreActivity.this,common.FAVORITE_DATA_FILE, buffer);} else {// 关注if (!isFileBlank) {// 如果buffer有数据buffer += ",";}buffer += mId;imageView.setImageResource(R.drawable.yellow_star);Toast.makeText(ScoreActivity.this, "该场比赛已成功关注！",Toast.LENGTH_SHORT).show();FileUtils.WriteActivityFile(ScoreActivity.this,common.FAVORITE_DATA_FILE, buffer);}}});?