下面是我的代码我想添加删除listview消息，当用户点击长按选择的消息将从列表视图中删除，并且数据库帮助我如何做到这一点我的代码，所以如何删除选定的消息表单列表视图和数据库有什么想法？
public class MsgActivity extends BackBaseActivity{
ImageView back;
Button writemsg;
ListView msglist;
List<MessageModel> msgarray;
MessageAdapter msgadapter;
ImageView scroll_down;
ImageView scroll_up;
int x = 1;
public static Activity msgactivity;;
Handler handle = new Handler() {
public void handleMessage(android.os.Message msg) {
super.handleMessage(msg);
CommonObjects.hideProgress();
msgadapter = new MessageAdapter(MsgActivity.this,
msgarray);
msglist.setAdapter(msgadapter);
}catch (Exception e) {
// TODO: handle exception
}
}
if(msg.what == 1){
Toast.makeText(MsgActivity.this, "No Messages",
Toast.LENGTH_SHORT).show();
}
}
};
@Override
protected void onRestart() {
if(CommonObjects.getLogoutreject().equals("1") && CommonObjects.logout){
finish();
}
super.onRestart();
}
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.msgactivity);
back = (ImageView)findViewById(R.id.magback);
msglist = (ListView)findViewById(R.id.msglist);
msgactivity = this;
CommonObjects.showProgress(MsgActivity.this, "Loading messages");
new Thread() {
public void run() {
Looper.prepare();
try{
DatabaseHandler db = new
DatabaseHandler(MsgActivity.this);
msgarray = db.getAllmesages();
android.os.Message alertMessage = new android.os.Message();
alertMessage.what = 2;
handle.sendMessage(alertMessage);
}catch (Exception e) {
e.getStackTrace();
android.os.Message alertMessage = new
android.os.Message();
alertMessage.what = 1;
handle.sendMessage(alertMessage);
}
}
}.start();
}
答案 0 :(得分：0)
试试这样。
lv.setOnItemLongClickListener(new OnItemLongClickListener() {
// setting onItemLongClickListener and passing the position to the function
@Override
public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
int position, long arg3) {
String[] delete = names2.get(i);
String idString = delete[0];
long idLong = Long.valueOf(idString);
Log.d("Deleting...", idLong + "");
dataManipulator.delete(idLong);
names2.remove(i);
}
});
其中names2是您的List数组。
并在Datamanipulator类中添加以下
public boolean delete(long rowId) {
/** this method deletes by id, the first column in your database */
return db.delete(TABLE_NAME, KEY_ROWID + "=" + rowId, null) > 0;
}
答案 1 :(得分：0)
如果要删除listview和数据库中的任何数据，只需执行此操作
在你的主要活动课
中 delete.setOnClickListener(new OnClickListener() {
@Override
public void onClick(final View v) {
// TODO Auto-generated method stub
DatabaseHandler dBHandler = new DatabaseHandler(
activity.getApplicationContext());
dBHandler.Delete_Contact(user_id);
Main_Screen.this.onResume();
}
});
并在您的数据库处理程序类中，使用此
// Deleting single contact
public void Delete_Contact(int id) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_CONTACTS, KEY_ID + " = ?",
new String[] { String.valueOf(id) });
db.close();
}
答案 2 :(得分：0)
DataBaseManager data = new DataBaseManager(context.getApplicationContext());
String QUERY = "SELECT * FROM Cart Where id= "your id";
Cursor cursor = data.selectQuery(QUERY);
int count = cursor.getCount();
if (count <= 0) {
}
else {
data.Delete("YOUR DATABASE NAME", "YOUR ID");
list.remove(position);
notifyDataSetChanged();
}
DatabaseMangerClass
public class DataBaseManager extends SQLiteOpenHelper {
// The Android's default system path of your application database.
@SuppressLint("SdCardPath")
private static String DB_PATH = "data/data/com.Salsoft.pharmapacks/";
private static String DB_NAME = "Cart.sqlite";
private SQLiteDatabase myDataBase;
private SQLiteDatabase myData;
private Context myContext;
// /data/data/com.salsoft.savingdata/db/SavingData.sqlite
/**
* Constructor Takes and keeps a reference of the passed context in order to
* access to the application assets and resources.
*
* @param context
*/
public DataBaseManager(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
Boolean isSDPresent = android.os.Environment.getExternalStorageState()
.equals(android.os.Environment.MEDIA_MOUNTED);
if (isSDPresent) {
// yes SD-card is present
} else {
// Sorry
}
}
/**
* Creates a empty database on the system and rewrites it with your own
* database.
* */
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (dbExist) {
// do nothing - database already exist
} else {
File directory = new File(DB_PATH);
directory.mkdirs();
CopyFiles();
}
}
private void CopyFiles() {
try {
InputStream is = myContext.getAssets().open(DB_NAME);
File outfile = new File(DB_PATH, DB_NAME);
outfile.getParentFile().mkdirs();
outfile.createNewFile();
if (is == null) {
throw new RuntimeException("stream is null");
} else {
FileOutputStream out = new FileOutputStream(outfile);
byte buf[] = new byte[128];
do {
int numread = is.read(buf);
if (numread <= 0)
break;
out.write(buf, 0, numread);
} while (true);
is.close();
out.close();
}
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/**
* Check if the database already exist to avoid re-copying the file each
* time you open the application.
*
* @return true if it exists, false if it doesn't
*/
private boolean checkDataBase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
} catch (SQLiteException e) {
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null ? true : false;
}
public void openDataBase() throws SQLException {
// Open the database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
}
@Override
public synchronized void close() {
if (myDataBase != null)
myDataBase.close();
super.close();
}
public void insert(String table, String num, ContentValues content) {
String myPath = DB_PATH + DB_NAME;
myData = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
myData.insert(table, num, content);
}
public void update(String tablename, ContentValues content, String productid) {
String myPath = DB_PATH + DB_NAME;
myData = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
myData.update(tablename, content, "productid = ?",
new String[] { productid });
}
public void Delete(String tablename, String productid) {
String myPath = DB_PATH + DB_NAME;
myData = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
myData.delete(tablename, "productid = ?", new String[] { productid });
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
// ---retrieve records---
public Cursor selectQuery(String query) throws SQLException {
String myPath = DB_PATH + DB_NAME;
myData = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READONLY);
Cursor mCursor = myData.rawQuery(query, null);
mCursor.moveToFirst();
myData.close();
return mCursor;
}
// //////// For Insert And Update Data ////////
public void insert_update(String query) throws SQLException {
String myPath = DB_PATH + DB_NAME;
myData = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
myData.execSQL(query);
myData.close();
}
}