Question

I have ArrayList of object like

ArrayList<DataCCHeading>CC1=new ArrayList<DataCCHeading>();
ArrayList<DataCCHeading>hd=new ArrayList<DataCCHeading>(result);

for (DataCCHeading dataCCHeading : hd)
{
    if(dataCCHeading.Ownername==TAG_CC1HeadingData)
    {
        CC1.add(dataCCHeading);
    }
}

What I want to do to store external storage SDCard so that I can later get that data other wise I have to request it again from server. My question is how to store Arraylist of object to store and retrieve from SDCard?

Answer 1

You do it like this:

  //use getExternalStorageState to determine if there is an sd card
  if (Environment.getExternalStorageState() == null) {
                    directory = new File(Environment.getDataDirectory()
                            + "/RobotiumTestLog/");
                    photoDirectory = new File(Environment.getDataDirectory()
                            + "/Robotium-Screenshots/");
                    /*
                     * this checks to see if there are any previous test photo files
                     * if there are any photos, they are deleted for the sake of
                     * memory
                     */
                     //if the directory exists, delete files in directory
                    if (photoDirectory.exists()) {
                        File[] dirFiles = photoDirectory.listFiles();
                        if (dirFiles.length != 0) {
                            for (int ii = 0; ii <= dirFiles.length; ii++) {
                                dirFiles[ii].delete();
                            }
                        }
                    }
                    // if no directory exists, create new directory
                    if (!directory.exists()) {
                        directory.mkdir();
                    }

                    // if phone DOES have sd card
                } else if (Environment.getExternalStorageState() != null) {
                    // search for directory on SD card
                    directory = new File(Environment.getExternalStorageDirectory()
                            + "/RobotiumTestLog/");
                    photoDirectory = new File(
                            Environment.getExternalStorageDirectory()
                                    + "/Robotium-Screenshots/");
                    if (photoDirectory.exists()) {
                        File[] dirFiles = photoDirectory.listFiles();
                        if (dirFiles.length > 0) {
                            for (int ii = 0; ii < dirFiles.length; ii++) {
                                dirFiles[ii].delete();
                            }
                            dirFiles = null;
                        }
                    }
                    // if no directory exists, create new directory to store test
                    // results
                    if (!directory.exists()) {
                        directory.mkdir();
                    }
                }

It is a pretty easy process. What I did here was check to see if there is an SD card, if there is, I search for a directory, if no directory, I create one. If there is a directory and it has content I erase it. You don’t have to do all that. If you like, you can use the the Environment.getExternalStorageDirectory(). This will get the SD card. From there you create a bufferedWriter and write. You also need to add <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> in your manifest. If you have any questions, let me know.

I hope this helps!