Android编程：通过复选框从listview中查找数据库密钥id。待办事项清单/杂货清单
我是一个使用Android/Java编程的初学者，我在不太难完成的事情上遇到了麻烦。我使用的代码是我试图从谷歌记事本v1中改编的。我意识到这个版本远未完成，但它是最精简的开始 我试图做的是修改列表，使其包含注释，但使其功能类似于待办事项列表，可以向列表中添加项目。在每个项目旁边，都需要有一个复选框。我正在将复选框状态写入数据库，而我遇到的问题是从数据库中收集每个复选框的相关id。如果我手动指定列表中需要的项目，它可以工作，但是我无法获得OnClick（setChk）来提取数据库所需的id。我在下面发布了4个重要的代码文件 我在尝试实现这一点时遇到了很多问题，在编程的这一点上，我只是在创造一些东西来获得编程技能。如果有人有我所描述的功能正常的待办事项列表，我将非常感谢看到一个工作的示例代码。我非常感谢任何帮助 Finished.javaAndroid编程：通过复选框从listview中查找数据库密钥id。待办事项清单/杂货清单,android,sqlite,listview,checkbox,onclick,Android,Sqlite,Listview,Checkbox,Onclick,我是一个使用Android/Java编程的初学者，我在不太难完成的事情上遇到了麻烦。我使用的代码是我试图从谷歌记事本v1中改编的。我意识到这个版本远未完成，但它是最精简的开始 我试图做的是修改列表，使其包含注释，但使其功能类似于待办事项列表，可以向列表中添加项目。在每个项目旁边，都需要有一个复选框。我正在将复选框状态写入数据库，而我遇到的问题是从数据库中收集每个复选框的相关id。如果我手动指定列表中需要的项目，它可以工作，但是我无法获得OnClick（setChk）来提取数据库所需的id。我在下
notes_row.xml
新的完成。爪哇
private void fillData() {
Cursor c = mDbHelper.fetchAllNotes();
startManagingCursor(c);
String[] from = new String[] { NotesDbAdapter.KEY_TITLE, NotesDbAdapter.KEY_CHECK };
int[] to = new int[] { R.id.text1, R.id.CheckBox1 };
// Now create an array adapter and set it to display using our row
final SimpleCursorAdapter notes = new SimpleCursorAdapter(this, R.layout.notes_row, c, from, to);
notes.setViewBinder(new SimpleCursorAdapter.ViewBinder() {
public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
int nCheckedIndex = cursor.getColumnIndexOrThrow(NotesDbAdapter.KEY_CHECK);
if (columnIndex == nCheckedIndex) {
CheckBox cb = (CheckBox) view;
boolean bChecked = (cursor.getInt(nCheckedIndex) != 0);
cb.setChecked(bChecked);
//call if after setChecked so the listener isn't called there already
cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
int position = getListView().getPositionForView(buttonView);
Cursor c = notes.getCursor();
if (c.moveToPosition(position)) {
int rowid = c.getInt(c.getColumnIndex(NotesDbAdapter.KEY_ROWID));
if (isChecked) {
mDbHelper.updateChk(rowid, "1");
} else {
mDbHelper.updateChk(rowid, "0");
}
}
}
});
return true;
}
return false;
}
});
setListAdapter(notes);
}
03-11 10:38:53.486:E/AndroidRuntime（5611）：在dalvik.system.NativeStart.main（本机方法）首先将
SimpleCursorAdapterpublic void setChk(View view) {
int position = getListView().getPositionForView(view);
Cursor c = notes.getCursor();
if (c.moveToPosition(position)) {
int rowid = c.getInt(c.getColumnIndex(NotesDbAdapter.KEY_ROWID)
//your code
}
}
OnClickListenerOnCheckedChangeListenerfillData（）：
new SimpleCursorAdapter.ViewBinder() {
public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
int nCheckedIndex = cursor.getColumnIndexOrThrow(NotesDbAdapter.KEY_CHECK);
if (columnIndex == nCheckedIndex) {
CheckBox cb = (CheckBox) view;
boolean bChecked = (cursor.getInt(nCheckedIndex) != 0);
cb.setChecked(bChecked);
//call if after setChecked so the listener isn't called there already
cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
int position = getListView().getPositionForView(buttonView);
Cursor c = notes.getCursor();
if (c.moveToPosition(position)) {
int rowid = c.getInt(c.getColumnIndex(NotesDbAdapter.KEY_ROWID)
if (isChecked) {
//TODO update db
} else {
//TODO update db
}
}
}
return true;
}
return false;
}
});
谢谢你，先生！这很有效，我现在已经把一切都准备好了，但是。。。就像你说的，听着
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class NotesDbAdapter {
public static final String KEY_TITLE = "title";
public static final String KEY_BODY = "body";
public static final String KEY_ROWID = "_id";
public static final String KEY_CHECK = "check";
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 = 3;
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 check) {
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_TITLE, title);
initialValues.put(KEY_BODY, body);
initialValues.put(KEY_BODY, check);
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_CHECK}, null, 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_CHECK}, 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
* @param check
* @return true if the note was successfully updated, false otherwise
*/
public boolean updateNote(long rowId, String title, String body, String check) {
ContentValues args = new ContentValues();
args.put(KEY_TITLE, title);
args.put(KEY_BODY, body);
args.put(KEY_CHECK, check);
return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}
}
private void fillData() {
Cursor c = mDbHelper.fetchAllNotes();
startManagingCursor(c);
String[] from = new String[] { NotesDbAdapter.KEY_TITLE, NotesDbAdapter.KEY_CHECK };
int[] to = new int[] { R.id.text1, R.id.CheckBox1 };
// Now create an array adapter and set it to display using our row
final SimpleCursorAdapter notes = new SimpleCursorAdapter(this, R.layout.notes_row, c, from, to);
notes.setViewBinder(new SimpleCursorAdapter.ViewBinder() {
public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
int nCheckedIndex = cursor.getColumnIndexOrThrow(NotesDbAdapter.KEY_CHECK);
if (columnIndex == nCheckedIndex) {
CheckBox cb = (CheckBox) view;
boolean bChecked = (cursor.getInt(nCheckedIndex) != 0);
cb.setChecked(bChecked);
//call if after setChecked so the listener isn't called there already
cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
int position = getListView().getPositionForView(buttonView);
Cursor c = notes.getCursor();
if (c.moveToPosition(position)) {
int rowid = c.getInt(c.getColumnIndex(NotesDbAdapter.KEY_ROWID));
if (isChecked) {
mDbHelper.updateChk(rowid, "1");
} else {
mDbHelper.updateChk(rowid, "0");
}
}
}
});
return true;
}
return false;
}
});
setListAdapter(notes);
}
public void setChk(View view) {
int position = getListView().getPositionForView(view);
Cursor c = notes.getCursor();
if (c.moveToPosition(position)) {
int rowid = c.getInt(c.getColumnIndex(NotesDbAdapter.KEY_ROWID)
//your code
}
}
new SimpleCursorAdapter.ViewBinder() {
public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
int nCheckedIndex = cursor.getColumnIndexOrThrow(NotesDbAdapter.KEY_CHECK);
if (columnIndex == nCheckedIndex) {
CheckBox cb = (CheckBox) view;
boolean bChecked = (cursor.getInt(nCheckedIndex) != 0);
cb.setChecked(bChecked);
//call if after setChecked so the listener isn't called there already
cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
int position = getListView().getPositionForView(buttonView);
Cursor c = notes.getCursor();
if (c.moveToPosition(position)) {
int rowid = c.getInt(c.getColumnIndex(NotesDbAdapter.KEY_ROWID)
if (isChecked) {
//TODO update db
} else {
//TODO update db
}
}
}
return true;
}
return false;
}
});