android programming 2

This slides explain how to save data and files on android

Transcript

1. Android Programming Saving Data and Files
2. Shared preferences Editor edit = sp.edit(); sp.putString(“key”, ”value”); edit.commit(); sp.getString(“key”, ”default”; Android programming SharedPreferences sp= PreferenceManager. getDefaultSharedPreferences(this);
3. Internal Storage //API Level 8, see developers.android.com for more. String filename = "hello_file"; String string = "hello world!"; FileOutputStream fos = openFileOutput (filename, Context.MODE_PRIVATE); fos.write(string.getBytes()); fos.close(); FileInputStream fis = openFileInput (filename, Context.MODE_PRIVATE); String s=new String(fis.read()); fos.close(); Android programming
4. External Storage //API Level 8, see developers.android.com for more. String state = Environment .getExternalStorageState(); // Managing SD state //Private storage File file = new File (getExternalFilesDir(null), ”MyFile.jpg"); //Or public one File path = Environment .getExternalStoragePublicDirectory(null); Android programming
5. ListActivity A normal Activity with a ListView Inside. Android programming
6. Using ListActivity public class MyListActivity extends ListActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); String[] values = new String[]{"first", "second", "third","forth"}; ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, values); setListAdapter(adapter); } ›  } Android programming
7. Dialogs JOptionPane = Dialog Android programming
8. Using Dialogs AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener(){ public void onClick(DialogInterface dialog, int id) { // User clicked OK button } } }); builder.setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { // User cancelled the dialog } }); AlertDialog dialog = builder.create(); dialog.show(); Android programming
9. What should we do today? ›  Your login credential should be saved in shared preferences. ›  After the login the applications show me the list of color’s names, if I click on a color’s name a dialog will popup to ask me if I want to save that color name on my internal storage. Android programming
10. Credit ›  ListActivity Image ›  Dialog image