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);

 

 

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);
					}
				}
			});