我已经完成了Notepad教程v3，但有一点我无法弄清楚如何在视图模式下打开笔记而不是编辑模式。
我用按钮和东西制作了自己的记事本，但仍无法查看它们。 助手类
public static final String KEY_TITLE = "title";
public static final String KEY_BODY = "body";
public static final String KEY_ROWID = "_id";
private static final String TAG = "NotesDbAdapter";
private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;
/**
* Database creation sql statement
*/
private static final String DATABASE_CREATE =
"create table notes (_id integer primary key autoincrement, "
+ "title text not null, body text not null);";
private static final String DATABASE_NAME = "data";
private static final String DATABASE_TABLE = "notes";
private static final int DATABASE_VERSION = 2;
private final Context mCtx;
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(DATABASE_CREATE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS notes");
onCreate(db);
}
}
/**
* Constructor - takes the context to allow the database to be
* opened/created
*
* @param ctx the Context within which to work
*/
public NotesDbAdapter(Context ctx) {
this.mCtx = ctx;
}
/**
* Open the notes database. If it cannot be opened, try to create a new
* instance of the database. If it cannot be created, throw an exception to
* signal the failure
*
* @return this (self reference, allowing this to be chained in an
* initialization call)
* @throws SQLException if the database could be neither opened or created
*/
public NotesDbAdapter open() throws SQLException {
mDbHelper = new DatabaseHelper(mCtx);
mDb = mDbHelper.getWritableDatabase();
return this;
}
public void close() {
mDbHelper.close();
}
/**
* Create a new note using the title and body provided. If the note is
* successfully created return the new rowId for that note, otherwise return
* a -1 to indicate failure.
*
* @param title the title of the note
* @param body the body of the note
* @return rowId or -1 if failed
*/
public long createNote(String title, String body) {
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_TITLE, title);
initialValues.put(KEY_BODY, body);
return mDb.insert(DATABASE_TABLE, null, initialValues);
}
/**
* Delete the note with the given rowId
*
* @param rowId id of note to delete
* @return true if deleted, false otherwise
*/
public boolean deleteNote(long rowId) {
return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}
/**
* Return a Cursor over the list of all notes in the database
*
* @return Cursor over all notes
*/
public Cursor fetchAllNotes() {
return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_TITLE,
KEY_BODY}, null, null, null, null, null);
}
/**
* Return a Cursor positioned at the note that matches the given rowId
*
* @param rowId id of note to retrieve
* @return Cursor positioned to matching note, if found
* @throws SQLException if note could not be found/retrieved
*/
public Cursor fetchNote(long rowId) throws SQLException {
Cursor mCursor =
mDb.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
KEY_TITLE, KEY_BODY}, KEY_ROWID + "=" + rowId, null,
null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
/**
* Update the note using the details provided. The note to be updated is
* specified using the rowId, and it is altered to use the title and body
* values passed in
*
* @param rowId id of note to update
* @param title value to set note title to
* @param body value to set note body to
* @return true if the note was successfully updated, false otherwise
*/
public boolean updateNote(long rowId, String title, String body) {
ContentValues args = new ContentValues();
args.put(KEY_TITLE, title);
args.put(KEY_BODY, body);
return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}
}
主要课程
public class Notepadv3 extends ListActivity {
private static final int ACTIVITY_CREATE=0;
private static final int ACTIVITY_EDIT=1;
private static final int INSERT_ID = Menu.FIRST;
private static final int DELETE_ID = Menu.FIRST + 1;
private NotesDbAdapter mDbHelper;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.notes_list);
mDbHelper = new NotesDbAdapter(this);
mDbHelper.open();
fillData();
registerForContextMenu(getListView());
}
private void fillData() {
Cursor notesCursor = mDbHelper.fetchAllNotes();
startManagingCursor(notesCursor);
// Create an array to specify the fields we want to display in the list (only TITLE)
String[] from = new String[]{NotesDbAdapter.KEY_TITLE};
// and an array of the fields we want to bind those fields to (in this case just text1)
int[] to = new int[]{R.id.text1};
// Now create a simple cursor adapter and set it to display
SimpleCursorAdapter notes =
new SimpleCursorAdapter(this, R.layout.notes_row, notesCursor, from, to);
setListAdapter(notes);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
menu.add(0, INSERT_ID, 0, R.string.menu_insert);
return true;
}
@Override
public boolean onMenuItemSelected(int featureId, MenuItem item) {
switch(item.getItemId()) {
case INSERT_ID:
createNote();
return true;
}
return super.onMenuItemSelected(featureId, item);
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
menu.add(0, DELETE_ID, 0, R.string.menu_delete);
}
@Override
public boolean onContextItemSelected(MenuItem item) {
switch(item.getItemId()) {
case DELETE_ID:
AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
mDbHelper.deleteNote(info.id);
fillData();
return true;
}
return super.onContextItemSelected(item);
}
private void createNote() {
Intent i = new Intent(this, NoteEdit.class);
startActivityForResult(i, ACTIVITY_CREATE);
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
Intent i = new Intent(this, NoteEdit.class);
i.putExtra(NotesDbAdapter.KEY_ROWID, id);
startActivityForResult(i, ACTIVITY_EDIT);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
super.onActivityResult(requestCode, resultCode, intent);
fillData();
}
}
答案 0 :(得分：2)
您可以创建新活动。如果你想快速和肮脏，请复制和修改NoteEdit类中的东西。 如果你有时间，你应该花一些时间考虑设计，并按照 DRY 进行操作，因为Code-Guru建议“复制和粘贴编码是一种糟糕的设计”。
public class NoteView extends Activity {
private NotesDbAdapter mDbHelper;
private TextView mTitleText;
private TextView mBodyText;
private Long mRowId;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mDbHelper = new NotesDbAdapter(this);
mDbHelper.open();
setContentView(R.layout.note_view);
setTitle(R.string.edit_note);
mTitleText = (TextView) findViewById(R.id.title);
mBodyText = (TextView) findViewById(R.id.body);
mRowId = (savedInstanceState == null) ? null
: (Long) savedInstanceState
.getSerializable(NotesDbAdapter.KEY_ROWID);
if (mRowId == null) {
Bundle extras = getIntent().getExtras();
mRowId = extras != null ? extras.getLong(NotesDbAdapter.KEY_ROWID)
: null;
}
populateFields();
}
private void populateFields() {
if (mRowId != null) {
Log.v("NoteView", "id "+ mRowId);
Cursor note = mDbHelper.fetchNote(mRowId);
//startManagingCursor(note);
mTitleText.setText(note.getString(note
.getColumnIndexOrThrow(NotesDbAdapter.KEY_TITLE)));
mBodyText.setText(note.getString(note
.getColumnIndexOrThrow(NotesDbAdapter.KEY_BODY)));
}
}
}
找到一个按钮或可以触发该活动的地方。
public void onClick(View v) {
Intent i = new Intent(mCtx, NoteView.class);
i.putExtra(NotesDbAdapter.KEY_ROWID, id);
mCtx.startActivity(i);
}
答案 1 :(得分：0)
如您所知，您可以使用Activity中的“附加内容”将数据发送到Intent。要确定数据是处于“查看”模式还是“编辑”模式，只需发送boolean值即可指示它是什么。然后，接收Activity可以检查boolean“额外”，并根据该标记禁用或启用所有可编辑视图。
答案 2 :(得分：0)
曾几何时，你必须在纸质记事本中记下笔记。] 2
public class FontTypePreference extends DialogPreference {
private List<String> fonts = null;
private int selected;
public FontTypePreference(Context context, AttributeSet attrs) {
super(context, attrs);
SharedPreferences sharedPref = PreferenceManager
.getDefaultSharedPreferences(getContext());
String font = sharedPref.getString("font", "Monospace");
if (font.equals("Serif"))
selected = 1;
else if (font.equals("Sans Serif"))
selected = 2;
else
selected = 0;
}
protected void onPrepareDialogBuilder(AlertDialog.Builder builder) {
// Data has changed, notify so UI can be refreshed!
builder.setTitle("Choose a font type");
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
Editor editor = PreferenceManager.getDefaultSharedPreferences(
getContext()).edit();
if (selected == 0)
editor.putString("font", "Monospace");
else if (selected == 1)
editor.putString("font", "Serif");
else
editor.putString("font", "Sans Serif");
editor.commit();
notifyChanged();
}
});
builder.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
// do nothing on a cancel
}
});
// load the font names
String[] arrayOfFonts = { "Monospace", "Serif", "Sans Serif" };
fonts = Arrays.asList(arrayOfFonts);
FontTypeArrayAdapter adapter = new FontTypeArrayAdapter(getContext(),
android.R.layout.simple_list_item_single_choice, fonts);
builder.setSingleChoiceItems(adapter, selected,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
selected = which;
}
});
}
public class FontTypeArrayAdapter extends ArrayAdapter<String> {
public FontTypeArrayAdapter(Context context, int resource,
List<String> objects) {
super(context, resource, objects);
}
public View getView(int position, View convertView, ViewGroup parent) {
View v = super.getView(position, convertView, parent);
final TextView tv = (TextView) v;
final String option = tv.getText().toString();
if (option.equals("Serif"))
tv.setTypeface(Typeface.SERIF);
else if (option.equals("Sans Serif"))
tv.setTypeface(Typeface.SANS_SERIF);
else if (option.equals("Monospace"))
tv.setTypeface(Typeface.MONOSPACE);
tv.setTextColor(Color.BLACK);
tv.setPadding(10, 3, 3, 3);
return v;
}
}
}