如何将数据从 sqlite 数据库传递到另一个活动？

Question

我有一个包含列 {id,eng,kurd,ar} 的数据库，并从中填充了一个列表视图，该列表视图仅显示数据库中的 {eng}。当用户单击列表视图中的项目时，我想传递具有相同 {id} 的 {eng,kurd,ar}，但是当我单击一个项目时，我的应用程序崩溃，但其他一切正常，非其他类的[适配器，sqliteopenhelper]

MainActivity.class

package com.rawa.rawadict;

import android.content.Intent;
import android.database.Cursor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;

import java.io.IOException;
import java.sql.SQLException;
import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    Adapter adapter;
    ArrayList<Item> myList = new ArrayList<Item>();
    ListView myListView;
    Databasehelper myDbHelper = new Databasehelper(this);
    String engRes,kurdRes,arRes;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        try {
            myDbHelper.createDatabase();
            myDbHelper.openDatabase();
        } catch (IOException e) {

            throw new Error("Unable to create database");
        }
        Cursor cursor = myDbHelper.QueryData("select * from zankodict");
        if (cursor != null) {
            if (cursor.moveToFirst()) {
                do {
                    Item itemm = new Item();
                    itemm.setId(cursor.getString(0));
                    itemm.setEng(cursor.getString(1));
                    myList.add(itemm);
                } while (cursor.moveToNext());
            }
        }
        adapter = new Adapter(this, R.layout.single_row, myList);
        myListView = (ListView) findViewById(R.id.lView);
        myListView.setAdapter(adapter);
        adapter.notifyDataSetChanged();

    myListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            TextView text_id = (TextView) view.findViewById(R.id.tid);
            String sel_id = text_id.getText().toString();
            Cursor cursor = myDbHelper.QueryData("SELECT * FROM zankodict WHERE id =" + sel_id);
            if (cursor != null) {
                if (cursor.moveToFirst()) {
                    do {
                        engRes = cursor.getString(1);
                        kurdRes=cursor.getString(2);
                        arRes= cursor.getString(3);
                    } while (cursor.moveToNext());
                }
            }
            // create intent to start another activity
            Intent intent = new Intent(MainActivity.this, Result.class);
            // add the selected text item to our intent.
            Bundle extras = new Bundle();
            extras.putString("eng",engRes);
            extras.putString("kurd",kurdRes);
            extras.putString("ar",arRes);
            intent.putExtras(extras);
            startActivity(intent);
        }
    }) ;


    }
}

Result.class

package com.rawa.rawadict;


import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;

import java.io.IOException;
import java.util.ArrayList;

public class Result extends AppCompatActivity {
    TextView etView2,ktView2,atView2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.result_view);
        etView2 = (TextView) findViewById(R.id.etextView2);
        ktView2 = (TextView) findViewById(R.id.ktextView2);
        atView2 = (TextView) findViewById(R.id.atextView2);

        Intent intent = getIntent();
        Bundle extras = intent.getExtras();
        String enG = extras.getString("eng");
        String kurD = extras.getString("kurd");
        String aR = extras.getString("ar");
        etView2.setText(enG);
        etView2.setText(kurD);
        etView2.setText(aR);
        }
    }

我想将 Bundle 传递给 Result.class

Answer 1

将数据从活动传递到活动，特别是从您的数据库传递数据的最佳方法是传递一个 (id) 作为额外的意图，然后当您到达目标活动时，提取它并使用它来查询您的数据库身份证。

这将减少您必须通过您的意图实例的数据量。

但是，如果您只想传递 3 个项目，则可以使用 Intent Extras 而不是这样的 Bundle：

Intent intent = new Intent(MainActivity.this, Result.class);
intent.putExtra("eng",engRes);
intent.putExtra"kurd",kurdRes);
intent.putExtra("ar",arRes);

startActivity(intent);

在您的结果活动中提取它；

Intent intent = getIntent();
String enG = intent.getExtras().getString("eng");
String kurD = intent.getExtras().getString("kurd");
String aR = intent.getExtras().getString("ar");

我希望这会有所帮助，祝你好运！