if(Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())){
        cacheDir=mContext.getExternalCacheDir().getPath();
      }else {
        cacheDir=mContext.getCacheDir().getPath();
      }
 fileOutputStream=new FileOutputStream(cacheDir+"/"+url);

private void initFile() {
    if(Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())){
      cacheDir=mContext.getExternalCacheDir().getPath();
      Log.d(TAG,"have SD");
    }else {
      cacheDir=mContext.getCacheDir().getPath();
      Log.d(TAG," not have SD");
    }
    Log.d(TAG,cacheDir);
    File file=new File(cacheDir);
    if(!file.exists()) {
      Log.d(TAG, "file no exists");
      file.mkdirs();
    }
  }