伙计们，我太绝望了。编辑创建的项目的值时，重新输入片段后，我只会从位置0获得该项目，并从位置0开始将所有项目替换为与我编辑的值相同的所有项目。然后，当我删除任何项目时，一旦我重新输入片段，它将全部删除。很明显，我编辑时所有项目都已替换为相同的ID。 在这里，我通过了代码。希望您能对我有所帮助，谢谢。
我的用户表
public class UserTable{
public static final String TABLE_NAME = "Usuarios";
public static final String ID = "Usuarios_id";
public static final String USUARIOS_NAME = "Usuario_name";
public static final String NUMERO_NAME = "numero_name";
public static final String CLASE_NAME = "clase_name";
public static final String[] PROJECTION =
{ID, USUARIOS_NAME, NUMERO_NAME, CLASE_NAME};
public static final String CMD_CREATE_TABLE =
"CREATE TABLE IF NOT EXISTS " + TABLE_NAME + " ( "
+ ID + " INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL , "
+ USUARIOS_NAME + " TEXT , "
+ NUMERO_NAME + " TEXT , "
+ CLASE_NAME + " TEXT "
+ " );";
public static int id;
private SQLiteDatabase db;
public static ArrayList<UsuariosModel> getByArg(SQLiteDatabase db, String clase_name) {
Cursor c = db.query(
true,
UserTable.TABLE_NAME,
UserTable.PROJECTION,
CLASE_NAME + " = ?",
new String[]{clase_name},
//null,
//null,
null,
null,
null, null
);
//BATCH_ID+" = ?"
// new String[]{String.valueOf(id)}
Log.i("DatabaseContentCount", c.getCount() + "");
ArrayList<UsuariosModel> students = new ArrayList<>();
while (c.moveToNext()) {
students.add(
new UsuariosModel(
c.getInt(c.getColumnIndexOrThrow(ID)),
c.getString(c.getColumnIndexOrThrow(USUARIOS_NAME)),
c.getString(c.getColumnIndexOrThrow(NUMERO_NAME)),
c.getString(c.getColumnIndexOrThrow(CLASE_NAME))
)
);
}
c.close();
return students;
}
public static int deleteByBatchName(SQLiteDatabase db, String name) {
/*
We can just delete the parent expense row.
The ON DELETE CASCADE clause, will make sure the
refuel row is also deleted.
*/
try {
return db.delete(TABLE_NAME, CLASE_NAME + "= '" + name + "'", null);
db.execSQL("UPDATE " + TABLE_NAME + " set " + ID + " = (student_id-1) WHERE " + BatchTable.ID + " > " + id);
db.delete("SQLITE_SEQUENCE","NAME = ?",new String[]{TABLE_NAME});
} catch (NullPointerException e) {
e.printStackTrace();
return 0;
}
}
public static int deleteByStudentName(SQLiteDatabase db, String name) {
/*
We can just delete the parent expense row.
The ON DELETE CASCADE clause, will make sure the
refuel row is also deleted.
*/
try {
String query = "SELECT " + ID + " FROM " + TABLE_NAME + " WHERE " + USUARIOS_NAME + " = ?";
Cursor cursor = db.rawQuery(query, new String[]{name});
if (cursor != null) {
cursor.moveToFirst();
id = cursor.getInt(cursor.getColumnIndexOrThrow(ID));
}
int result = db.delete(TABLE_NAME, USUARIOS_NAME + "= ? ", new String[]{name});
Log.i("FetchID", id + "");
db.execSQL("UPDATE " + TABLE_NAME + " set " + ID + " = (Usuarios_id-1) WHERE " + ID + " > " + id);
db.delete("SQLITE_SEQUENCE", "NAME = ?", new String[]{TABLE_NAME});
return result;
} catch (NullPointerException e) {
e.printStackTrace();
return 0;
}
}
public static long save(SQLiteDatabase db, UsuariosModel usuarios) {
ContentValues cv = new ContentValues();
Log.i("StudentDetails", usuarios.getusuarios_name() + " " + usuarios.getnumero_name() + " " + usuarios.getclase_name());
cv.put(USUARIOS_NAME, usuarios.getusuarios_name());
cv.put(NUMERO_NAME, usuarios.getnumero_name());
cv.put(CLASE_NAME, usuarios.getclase_name());
//Log.i("himanshu", cv.size() + "");
long result = db.insert(TABLE_NAME, ID, cv);
Log.e("Result After Inserting", "" + result);
return result;
}
public static long updateItem(SQLiteDatabase db, UsuariosModel usuarios) {
ContentValues contentValues = new ContentValues();
contentValues.put("Usuario_name", usuarios.getusuarios_name());
long pepe = db.update( TABLE_NAME, contentValues, ID, null);
return pepe;
}
}
我的模型类
public class UsuariosModel {
long id;
String usuarios_name;
String numero_name;
String clase_name;
public UsuariosModel(long id, String usuarios_name, String numero_name, String clase_name)
{
this.id=id;
this.usuarios_name=usuarios_name;
this. numero_name= numero_name;
this.clase_name=clase_name;
}
public long getId() {
return id;
}
public UsuariosModel(String usuarios_name, String numero_name, String clase_name)
{
this.usuarios_name=usuarios_name;
this. numero_name= numero_name;
this.clase_name=clase_name;
}
public String getusuarios_name() {
return usuarios_name;
}
public void setusuarios_name(String usuarios_name) {
this.usuarios_name = usuarios_name;
}
public String getnumero_name() {
return numero_name;
}
public void setnumero_name(int numero_id) {
this.numero_name = numero_name;
}
public String getclase_name() {
return clase_name;
}
public void setclase_name(String clase_name) {
this.clase_name = clase_name;
}
public void setId(int id) {
this.id = id;
}
}
我的RecyclerAdapter
public class RecyclerUser extends
RecyclerView.Adapter<RecyclerUser.RecyclerViewHolderz> {
Context context;
LayoutInflater inflater;
private List<String> users_names_list;
UsuariosModel usertModel;
String batch_name;
ArrayList<String> student_list;
public RecyclerUser(Context context, List<String> users_names_list) {
this.context = context;
inflater = LayoutInflater.from(context);
this.users_names_list = users_names_list;
student_list = new ArrayList<String>();
this.notifyDataSetChanged();
this. modifyItem();
}
@Override
public RecyclerViewHolderz onCreateViewHolder(ViewGroup parent, int viewType)
{
View v = inflater.inflate(R.layout.item_list, parent, false);
RecyclerUser.RecyclerViewHolderz viewHolders = new RecyclerUser.RecyclerViewHolderz(v);
return viewHolders;
}
@Override
public void onBindViewHolder(final RecyclerUser.RecyclerViewHolderz holder,final int position) {
holder.tv1.setTag(position);
holder.tv1.setText((CharSequence) users_names_list.get(position));
holder.tv1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setTitle("Add new Student and its UserId");
LinearLayout layout = new LinearLayout(context);
layout.setOrientation(LinearLayout.VERTICAL);
// Set up the input
final EditText user_name = new EditText(context);
// Specify the type of input expected; this, for example, sets the input as a password, and will mask the text
user_name.setInputType(InputType.TYPE_CLASS_TEXT);
user_name.setHint("User Name");
layout.addView(user_name);
final EditText user_id = new EditText(context);
// Specify the type of input expected; this, for example, sets the input as a password, and will mask the text
user_id.setInputType(InputType.TYPE_CLASS_TEXT);
user_id.setHint("User Id");
layout.addView(user_id);
builder.setView(layout);
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String n = users_names_list.get(position);
// updating note text
// updating note in db
notifyItemChanged(position);
int position = holder.getAdapterPosition();
notifyDataSetChanged();
// refreshing the list
users_names_list.set(position, n);
getItemId(position);
usertModel = new UsuariosModel(0, user_name.getText().toString(), user_id.getText().toString(), batch_name);
final SQLiteDatabase db = MyDatabase.getInstance(context).getWritableDatabase();
UserTable.updateItem(db,usertModel);
users_names_list.set(position,user_name.getText().toString());
}
});
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
builder.show();
}
});
holder.tv1.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
final android.app.AlertDialog.Builder builder = new android.app.AlertDialog.Builder(context);
builder.setTitle("Delete");
builder.setMessage("Are you sure you want to delete it?");
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
users_names_list.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position, users_names_list.size());
final SQLiteDatabase db = MyDatabase.getInstance(context).getWritableDatabase();
UserTable.deleteByStudentName(db, holder.tv1.getText().toString());
}
});
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
builder.show();
return true;
}
});
}
public void updateData(ArrayList<String> viewModels) {
student_list.clear();
student_list.addAll(viewModels);
notifyDataSetChanged();
}
private String hola (int position) {
return student_list.get(position);
}
View.OnClickListener clickListener = new View.OnClickListener() {
@Override
public void onClick(View v) {
RecyclerUser.RecyclerViewHolderz hola = (RecyclerUser.RecyclerViewHolderz) v.getTag();
int position = hola.getPosition();
Toast.makeText(context, "This is position " + position, Toast.LENGTH_LONG).show();
}
};
@Override
public int getItemCount() {
return users_names_list.size();
}
public String getIteId(int position) {
return users_names_list.get(position);
}
public void modifyItem() {
notifyDataSetChanged();
}
private void notifyDataSetChanged(int position) {
notifyDataSetChanged();
}
public class RecyclerViewHolderz extends RecyclerView.ViewHolder {
TextView tv1;
ImageView imageView;
public RecyclerViewHolderz(View itemView) {
super(itemView);
imageView = (ImageView) itemView.findViewById(R.id.list_avatar);
tv1 = (TextView) itemView.findViewById(R.id.student_name_text_view);
}
}
}