我有sqlite数据库我成功从中获取了所有数据并将其存储在String数据中，然后使用另一个只有Toast的java类显示它。
现在我正在尝试将此数据发送到另一个活动。
如何实现这一目标？
NotesDbAdapter.java：
public class NotesDbAdapter {
public static final String KEY_TITLE = "title";
public static final String KEY_DATE = "date";
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, date 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, String date) {
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_TITLE, title);
initialValues.put(KEY_BODY, body);
initialValues.put(KEY_DATE, date);
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,KEY_DATE}, 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_DATE}, 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,String date) {
ContentValues args = new ContentValues();
args.put(KEY_TITLE, title);
args.put(KEY_BODY, body);
//This lines is added for personal reason
args.put(KEY_DATE, date);
//One more parameter is added for data
return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}
public String getALLData(){
mDb = mDbHelper.getWritableDatabase();
String[] columns={KEY_ROWID ,KEY_TITLE,KEY_BODY};
Cursor cursor = mDb.query(DATABASE_TABLE, columns, null, null, null, null, null);
StringBuffer buffer=new StringBuffer();
while (cursor.moveToNext()){
int cid=cursor.getInt(0);
String title=cursor.getString(1);
String body=cursor.getString(2);
buffer.append(cid+" "+title+" "+body+"\n");
}
return buffer.toString();
}}
我存储数据的NoteEdit活动：
public class NoteEdit extends Activity {
public static int numTitle = 1;
public static String curDate = "";
public static String curText = "";
private EditText mTitleText;
private EditText mBodyText;
private TextView mDateText;
private Long mRowId;
private Cursor note;
private NotesDbAdapter mDbHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mDbHelper = new NotesDbAdapter(this);
mDbHelper.open();
setContentView(R.layout.note_edit);
// getActionBar().setDisplayHomeAsUpEnabled(true);
setTitle(R.string.app_name);
mTitleText = (EditText) findViewById(R.id.title);
mBodyText = (EditText) findViewById(R.id.body);
mDateText = (TextView) findViewById(R.id.notelist_date);
long msTime = System.currentTimeMillis();
Date curDateTime = new Date(msTime);
SimpleDateFormat formatter = new SimpleDateFormat("d'/'M'/'y");
curDate = formatter.format(curDateTime);
mDateText.setText(""+curDate);
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();
}
public static class LineEditText extends EditText{
// we need this constructor for LayoutInflater
public LineEditText(Context context, AttributeSet attrs) {
super(context, attrs);
mRect = new Rect();
mPaint = new Paint();
mPaint.setStyle(Paint.Style.FILL_AND_STROKE);
mPaint.setColor(Color.BLUE);
}
private Rect mRect;
private Paint mPaint;
@Override
protected void onDraw(Canvas canvas) {
int height = getHeight();
int line_height = getLineHeight();
int count = height / line_height;
if (getLineCount() > count)
count = getLineCount();
Rect r = mRect;
Paint paint = mPaint;
int baseline = getLineBounds(0, r);
for (int i = 0; i < count; i++) {
canvas.drawLine(r.left, baseline + 1, r.right, baseline + 1, paint);
baseline += getLineHeight();
super.onDraw(canvas);
}
}
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
saveState();
outState.putSerializable(NotesDbAdapter.KEY_ROWID, mRowId);
}
@Override
protected void onPause() {
super.onPause();
saveState();
}
@Override
protected void onResume() {
super.onResume();
populateFields();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.noteedit_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.menu_about:
/* Here is the introduce about myself */
AlertDialog.Builder dialog = new AlertDialog.Builder(NoteEdit.this);
dialog.setTitle("About");
dialog.setMessage("This project "
);
dialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
dialog.show();
return true;
case R.id.menu_delete:
if(note != null){
note.close();
note = null;
}
if(mRowId != null){
mDbHelper.deleteNote(mRowId);
}
finish();
return true;
//speech button
case R.id.menu_speech:
//saveState();
//finish();
return true;
case R.id.menu_save:
saveState();
finish();
return true;
/* case android.R.id.home:
finish(); */
default:
return super.onOptionsItemSelected(item);
}
}
private void saveState() {
String title = mTitleText.getText().toString();
String body = mBodyText.getText().toString();
if(mRowId == null){
long id = mDbHelper.createNote(title, body, curDate);
if(id > 0){
mRowId = id;
}else{
Log.e("saveState","failed to create note");
}
}else{
if(!mDbHelper.updateNote(mRowId, title, body, curDate)){
Log.e("saveState","failed to update note");
}
}
}
private void populateFields() {
if (mRowId != null) {
note = mDbHelper.fetchNote(mRowId);
startManagingCursor(note);
mTitleText.setText(note.getString(
note.getColumnIndexOrThrow(NotesDbAdapter.KEY_TITLE)));
mBodyText.setText(note.getString(
note.getColumnIndexOrThrow(NotesDbAdapter.KEY_BODY)));
curText = note.getString(
note.getColumnIndexOrThrow(NotesDbAdapter.KEY_BODY));
}
}
public void viewDetails(View view){
String data= mDbHelper.getALLData();
Message.message(this,data);
}
}
答案 0 :(得分：0)
假设您正确地从数据库接收数据，您可以通过各种方式将它们发送到您应用的其他活动。其中最简单的是extras。点击该链接，然后导航到标题为“其他”的段落，了解如何使用它们。
答案 1 :(得分：0)
您可以传递
之类的值Intent intent=new Intent(getApplicationContext(), SecondActivity.class);
intent.putExtra("key1", "your value1 here");
intent.putExtra("key2", "your value2 here");
startActivity(intent);
并获得您的价值
String your_value1=getIntent().getStringExtra("key1");
String your_value2=getIntent().getStringExtra("key2");
你可以传递String，integer，float，... 你甚至可以传递一个完整的对象。