详解Android数据存储之Android 6.0运行时权限下文件存储的思考

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

/**
   * 获取app的根目录
   *
   * @return 文件缓存根路径
   */
  public static String getDiskCacheRootDir() {
    File diskRootFile;
    if (existsSdcard()) {
      diskRootFile = LeeApplication.getApp().getExternalCacheDir();
    } else {
      diskRootFile = LeeApplication.getApp().getCacheDir();
    }
    String cachePath;
    if (diskRootFile != null) {
      cachePath = diskRootFile.getPath();
    } else {
      throw new IllegalArgumentException("disk is invalid");
    }
    return cachePath;
  }
 这里需要判断sdcard是否可用
 /**
   * 判断外置sdcard是否可以正常使用
   *
   * @return
   */
  public static Boolean existsSdcard() {
    return Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState()) || !Environment.isExternalStorageRemovable();
  }

 /**
   * 获取相关功能业务目录
   *
   * @return 文件缓存路径
   */
  public static String getDiskCacheDir(String dirName) {
    String dir = String.format("%s/%s/", getDiskCacheRootDir(), dirName);
    File file = new File(dir);
    if (!file.exists()) {
      boolean isSuccess = file.mkdirs();
      if (isSuccess) {
        Log.d(TAG, "dir mkdirs success");
      }
    }
    return file.getPath();
  }

/**
   * 获取log日志根目录
   * @return
   */
  public static String getLogDir(){
    return getDiskCacheDir(LOG);
  }

  /**
   * 根据logName 获取log文件全路径
   * @param logName
   * @return
   */
  public static String getLogFilePath(String logName){
    return getLogDir()+logName;
  }