How to cache/save custom class object in Android?

Question

I want to save ArrayList<CustomClass>-object to somewhere in Android storage to retrieve quickly and display data in it.

Is this possible or not? If yes, then which technique will be suitable, SQLite or external storage?

Answer 1

example.

public class MyClass implements Serializable 
{
    private static final long serialVersionUID = 1L;

    public String title;
    public String startTime;
    public String endTime;
    public String day;

    public boolean classEnabled;


    public MyClass(String title, String startTime, boolean enable) {
        this.title = title;
        this.startTime = startTime;
        this.classEnabled = enable;
    }

    public boolean saveObject(MyClass obj) {   
        final File suspend_f=new File(SerializationTest.cacheDir, "test");

        FileOutputStream   fos  = null;
        ObjectOutputStream oos  = null;
        boolean            keep = true;

        try {
            fos = new FileOutputStream(suspend_f);
            oos = new ObjectOutputStream(fos);
            oos.writeObject(obj);
        } catch (Exception e) {
            keep = false;
        } finally {
            try {
                if (oos != null)   oos.close();
                if (fos != null)   fos.close();
                if (keep == false) suspend_f.delete();
        } catch (Exception e) { /* do nothing */ }
        }

        return keep;
    }

    public MyClass getObject(Context c) {
        final File suspend_f=new File(SerializationTest.cacheDir, "test");

        MyClass simpleClass= null;
        FileInputStream fis = null;
        ObjectInputStream is = null;

        try {
            fis = new FileInputStream(suspend_f);
            is = new ObjectInputStream(fis);
            simpleClass = (MyClass) is.readObject();
        } catch(Exception e) {
            String val= e.getMessage();
        } finally {
            try {
                if (fis != null)   fis.close();
                if (is != null)   is.close();
            } catch (Exception e) { }
        }

        return simpleClass;  
    }

and calling from activity

if(android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED))
    cacheDir=new File(android.os.Environment.getExternalStorageDirectory(),"MyCustomObject");
else
    cacheDir= getCacheDir();
if(!cacheDir.exists())
    cacheDir.mkdirs();

MyClass m = new MyClass("umer", "asif", true);
boolean result = m.saveObject(m);

if(result)
    Toast.makeText(this, "Saved object", Toast.LENGTH_LONG).show();
else
    Toast.makeText(this, "Error saving object", Toast.LENGTH_LONG).show();   

MyClass m = new MyClass();
MyClass c = m.getObject(this);

if(c!= null)
    Toast.makeText(this, "Retrieved object", Toast.LENGTH_LONG).show();
else
    Toast.makeText(this, "Error retrieving object", Toast.LENGTH_LONG).show();

dont forget to use write_external_storage permissions in manifest file.