一、首先添加权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>二、建立文件夹、生成文件并写入文本文件内容代码 private void initData() { String filePath = "/sdcard/Test/"; String fileName = "log.txt"; writeTxtToFile("txt content", filePath, fileName);} // 将字符串写入到文本文件中public void writeTxtToFile(String strcontent, String filePath, String fileName) { //生成文件夹之后，再生成文件，不然会出错 makeFilePath(filePath, fileName); String strFilePath = filePath+fileName; // 每次写入时，都换行写 String strContent = strcontent + "\r\n"; try { File file = new File(strFilePath); if (!file.exists()) { Log.d("TestFile", "Create the file:" + strFilePath); file.getParentFile().mkdirs(); file.createNewFile(); } RandomAccessFile raf = new RandomAccessFile(file, "rwd"); raf.seek(file.length()); raf.write(strContent.getBytes()); raf.close(); } catch (Exception e) { Log.e("TestFile", "Error on write File:" + e); }} // 生成文件public File makeFilePath(String filePath, String fileName) { File file = null; makeRootDirectory(filePath); try { file = new File(filePath + fileName); if (!file.exists()) { file.createNewFile(); } } catch (Exception e) { e.printStackTrace(); } return file;} // 生成文件夹public static void makeRootDirectory(String filePath) { File file = null; try { file = new File(filePath); if (!file.exists()) { file.mkdir(); } } catch (Exception e) { Log.i("error:", e+""); }