我的数据库处理程序有一个删除方法，用于删除数据库中的单行。但它没有正常工作。我的数据通过cardview显示在RecyclerView上。当我点击删除按钮时，它将被删除。但当我按意图去另一个活动并回到回收商的集装箱活动时，删除的数据又回来了！这意味着没有删除单行。
我的RecyclerViewAdapter：
package ir.qadamgahi.ramzdar;
import android.content.ClipData;
import android.content.ClipboardManager;
import android.content.Context;
import android.content.DialogInterface;
import android.os.Build;
import android.support.v7.app.AlertDialog;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;
import java.util.List;
import java.util.Objects;
import ir.qadamgahi.ramzdar.database.model.DatabaseHandler;
import ir.qadamgahi.ramzdar.database.model.Ramz;
/**
* Created by SMQ on 6/17/2017.
Qadamgahi.ir
@qadamgahiii instagram
*/
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.MyViewHolder> {
private List<Ramz> ramzList;
private ClipboardManager myClipboard;
private ClipData myClip;
private AlertDialog.Builder removeBuilder;
private AlertDialog removeAlert;
private DatabaseHandler dbHelper;
Ramz ramz = new Ramz();
Ramz ramzObj = new Ramz();
public class MyViewHolder extends RecyclerView.ViewHolder {
public TextView ramzTxtView, goalTxtView, usernameTxtView, usernameTxt;
public LinearLayout ramzUserLayout;
private ImageView copyImageBtn, deleteImgBtn, editImageBtn;
public MyViewHolder(View view) {
super(view);
ramzTxtView = (TextView) view.findViewById(R.id.ramzTxtView);
goalTxtView = (TextView) view.findViewById(R.id.goalTxtView);
usernameTxtView = (TextView) view.findViewById(R.id.usernameTxtView);
copyImageBtn = (ImageView) view.findViewById(R.id.copyImgbutton);
deleteImgBtn = (ImageView) view.findViewById(R.id.deleteImgBtn);
//editImageBtn = (ImageView) view.findViewById(R.id.editImageBtn);
usernameTxt = (TextView) view.findViewById(R.id.passUser);
ramzUserLayout = (LinearLayout) view.findViewById(R.id.pass_user_l);
}
}
public RecyclerViewAdapter(List<Ramz> ramzList) {
this.ramzList = ramzList;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.card_row, parent, false);
return new MyViewHolder(itemView);
}
@Override
public void onBindViewHolder(final MyViewHolder holder, final int position) {
ramz = ramzList.get(position);
holder.ramzTxtView.setText(ramz.get_ramz());
holder.goalTxtView.setText(ramz.get_goal());
holder.usernameTxtView.setText(ramz.get_username());
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
if (Objects.equals(ramz.get_username(), "")) {
holder.usernameTxtView.setVisibility(View.INVISIBLE);
holder.ramzUserLayout.setVisibility(View.INVISIBLE);
holder.usernameTxt.setVisibility(View.INVISIBLE);
}
}
holder.copyImageBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
myClipboard = (ClipboardManager) view.getContext().getSystemService(Context.CLIPBOARD_SERVICE);
myClip = ClipData.newPlainText("RAMZ", holder.ramzTxtView.getText().toString());
myClipboard.setPrimaryClip(myClip);
Toast.makeText(view.getContext(), R.string.makeSafe , Toast.LENGTH_LONG ).show();
Log.i("COPY", myClip.toString());
}
});
holder.deleteImgBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(final View view) {
//Alert dialog///////////////////////////////////////////////
removeBuilder = new AlertDialog.Builder(view.getContext());
removeBuilder.setMessage(R.string.areusure);
removeBuilder.setCancelable(true);
removeBuilder.setPositiveButton(
R.string.are,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dbHelper = new DatabaseHandler(view.getContext());
dbHelper.deleteRamz(ramz.get_id());
ramzList.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position,getItemCount());
Log.i("item deleted", String.valueOf(ramzList.size()));
}
}).setNegativeButton(
R.string.bikh,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
removeAlert = removeBuilder.create();
///////////////////////////////////////////////////////
removeAlert.show();
}
});
}
@Override
public int getItemCount() {
return ramzList.size();
}
}
我的DatabaseHandler：
package ir.qadamgahi.ramzdar.database.model;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import java.util.ArrayList;
import java.util.List;
/**
* Created by SMQ on 6/17/2017.
*/
public class DatabaseHandler extends SQLiteOpenHelper{
// All Static variables
private static final int DATABASE_VERSION = 4;
private static final String DATABASE_NAME = "ramzDB";
private static final String TABLE_RAMZ = "ramz";
private static final String KEY_ID = "id";
private static final String KEY_RAMZ = "ramz";
private static final String KEY_GOAL = "goal";
private static final String KEY_USERNAME= "username";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_RAMZ + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_RAMZ + " TEXT,"
+ KEY_GOAL + " TEXT," + KEY_USERNAME + " TEXT" + ")";
sqLiteDatabase.execSQL(CREATE_CONTACTS_TABLE);
}
// Adding new password
public void addRamz(Ramz ramz) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_RAMZ, ramz.get_ramz());
values.put(KEY_GOAL, ramz.get_goal());
values.put(KEY_USERNAME, ramz.get_username());
// Inserting Row
db.insert(TABLE_RAMZ, null, values);
db.close(); // Closing database connection
}
// Getting All passwords
public List<Ramz> getAllRamz() {
List<Ramz> ramzList = new ArrayList<Ramz>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_RAMZ;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Ramz ramz = new Ramz();
ramz.set_id(Integer.parseInt(cursor.getString(0)));
ramz.set_ramz(cursor.getString(1));
ramz.set_goal(cursor.getString(2));
ramz.set_username(cursor.getString(3));
// Adding password to list
ramzList.add(ramz);
} while (cursor.moveToNext());
}
// return password list
return ramzList;
}
// Getting single contact
Ramz getRamz(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_RAMZ, new String[] { KEY_ID,
KEY_RAMZ, KEY_GOAL, KEY_USERNAME }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Ramz ramz = new Ramz(Integer.parseInt(cursor.getString(0)),cursor.getString(1),
cursor.getString(2), cursor.getString(3));
// return contact
return ramz;
}
// Deleting single password
public void deleteRamz(int id) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_RAMZ, KEY_ID + " = ?",
new String[] { String.valueOf(id) });
db.close();
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
// Drop older table if existed
sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLE_RAMZ);
// Create tables again
onCreate(sqLiteDatabase);
}
}
如果您想要更多描述，请告诉我为您描述更多内容。
答案 0 :(得分：0)
你应该传递对象的KEY_ID以删除该对象而不是它在列表上的位置
Ramz ramz = new Ramz();
更新：
正如@Selvin所说，在你的适配器属性中删除这一行
onBindViewHolder并将final Ramz ramz = ramzList.get(position);
中的这一行更改为：
transform