个人中心
gpt4 book ai didi

java - 如何从 DbHandler 外部调用变量？

转载 作者：行者123 更新时间：2023-12-01 19:59:22 25 4
gpt4 key购买 nike

就我而言，我有 DbHandler.java 和 ActivityKategori.java。

我的问题是在DbHandler.java，我有查询条件

SELECT * FROM TBL_**** WHERE COLUMN1 = 'VARIABEL_FROM_ACT_KATEGORI' "

那就是变量值来自 bundle :D

我已经做了很多改变，但没有解决任何问题。

这是完整的代码

ActivityKategori.java

此 Activity 是从 bundle 中获取数据并将其值发送到 DBHandler 以获取 SQL CONDITION。

我知道有人会建议使用SharedPreference，但我对此感到困惑。

现在，我想学习使用Bundle或Intents传递

package ptacs.ekatalog.com.e_katalogproduk.activity;

import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

import ptacs.ekatalog.com.e_katalogproduk.R;
import ptacs.ekatalog.com.e_katalogproduk.adapter.KategoriAdapter;
import ptacs.ekatalog.com.e_katalogproduk.helper.Constant;
import ptacs.ekatalog.com.e_katalogproduk.helper.DBHandler;
import ptacs.ekatalog.com.e_katalogproduk.helper.RecyclerItemClickListener;
import ptacs.ekatalog.com.e_katalogproduk.model.Produk;

 public class ActivityKategori extends AppCompatActivity {

     private SwipeRefreshLayout swLayout2;
     private LinearLayout llayout2;
     private RecyclerView recyclerView;
     private LinearLayoutManager layoutManager;
     private KategoriAdapter adapter;
     private DBHandler dbHandler;
     private List<Produk> kategoriList = new ArrayList<>();
     private TextView tv1;
     String mMerkProduk;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_kategori);

        initRecyclerView();
        cekDataRecyclerView();


        if (getIntent().getExtras() != null) {
            Bundle bundle = getIntent().getExtras();
            mMerkProduk = bundle.getString(Constant.BUNDLE_MERK_PRODUK); //MERK kategori

        //Toolbar
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        setTitle(mMerkProduk);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        dbHandler = new DBHandler(this);
        }

        //dbHandler.getKategoryProduk(mMerkProduk);
        }
     private void initRecyclerView(){

         recyclerView = (RecyclerView) findViewById(R.id.rv_kategori);
         recyclerView.setHasFixedSize(true);
         layoutManager = new LinearLayoutManager(this);
         recyclerView.setLayoutManager(layoutManager);
         dbHandler = new DBHandler(ActivityKategori.this);
         kategoriList = dbHandler.getKategoryProduk(mMerkProduk); //GET VALUE STRING 
         //kategoriList = dbHandler.getKategoryProduk(); //OLD CODE to GET OBJECT
         adapter = new KategoriAdapter(kategoriList);
         recyclerView.setAdapter(adapter);
         adapter.notifyDataSetChanged();
        }




     private void cekDataRecyclerView() {

         if (adapter.getItemCount() == 0) {
             recyclerView.setVisibility(View.GONE);
         } else {
             recyclerView.setVisibility(View.VISIBLE);

             recyclerView.addOnItemTouchListener(
                     new RecyclerItemClickListener(getApplicationContext(), new RecyclerItemClickListener.OnItemClickListener() {
                         @Override
                         public void onItemClick(View view, int position) {
                             // TODO Handle item click

                             Bundle bundle = new Bundle();

                             //COMMIT MAS INDRA CS

                             bundle.putString(Constant.BUNDLE_JENIS_PRODUK, adapter.getItem(position).getJenis_produk());

                             Intent intent = new Intent(ActivityKategori.this, ActivityList.class);
                             intent.putExtras(bundle);
                             startActivity(intent);

                         }
                     })
             );
         }

         swLayout2 = (SwipeRefreshLayout) findViewById(R.id.sw_layout2);
         llayout2 = (LinearLayout) findViewById(R.id.ll_Layout);

         //Mengeset warna yang berputar
         swLayout2.setColorSchemeResources(R.color.colorAccent,R.color.colorPrimary);

         //Setting Listener yang akan dijalankan saat layar difresh
         swLayout2.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
             @Override
             public void onRefresh() {
                 refreshItem();
             }
             void refreshItem(){
                 initRecyclerView();
                 cekDataRecyclerView();
                 onItemLoad();
             }
             void onItemLoad(){
                 swLayout2.setRefreshing(false);
             }
         });
     }

     }

ActivityKategori.java

package ptacs.ekatalog.com.e_katalogproduk.helper;

/**
 * Created by Maxoto on 1/15/2018.
 */

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;

import ptacs.ekatalog.com.e_katalogproduk.model.Produk;

public class DBHandler extends SQLiteOpenHelper {

    private static final int DATABASE_VERSION = 2;
    private static final String DATABASE_NAME = "db_ekatalog"; // NAMA DATABASE
    private static final String TABLE_PRODUK = "tb_produk"; // NAMA TABEL
    private static final String COLUMN_ID = "id_produk"; // NAMA KOLOM ID
    private static final String COLUMN_KD = "kd_produk"; // KODE PRODUK
    private static final String COLUMN_NAMA = "nama_produk"; // NAMA KOLOM NAMA
    private static final String COLUMN_MERK = "merk_produk"; //MERK PRODUK
    private static final String COLUMN_JENIS = "jenis_produk"; //JENIS PRODUK
    private static final String COLUMN_VARIASI = "variasi_produk"; //VARIASI PRODUK
    private static final String COLUMN_FOTO = "foto_produk"; // FOTO PRODUK

    public DBHandler(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }
    // TODO : LANJUT SECTION 2
    // FUNGSI UNTUK MEMBUAT DATABASENYA
    @Override
    public void onCreate(SQLiteDatabase db) {
        String CREATE_USER_TABLE = "CREATE TABLE "
                + TABLE_PRODUK +
                "(" + COLUMN_ID + " INTEGER PRIMARY KEY,"
                + COLUMN_KD + " TEXT,"
                + COLUMN_NAMA + " TEXT, "
                + COLUMN_MERK + " TEXT, "
                + COLUMN_JENIS + " TEXT, "
                + COLUMN_VARIASI + " TEXT, "
                + COLUMN_FOTO + " TEXT" + ")";
        db.execSQL(CREATE_USER_TABLE);
    }

    // FUNGSI UNTUK MENGECEK DATABASE ADA ATAU TIDAK.
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_PRODUK);
        onCreate(db);
    }

    // FUNGSI UNTUK TAMBAH DATA PRODUK
    public void tambahProduk(Produk produk){
        SQLiteDatabase db = this.getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(COLUMN_KD, produk.getKd_produk());
        values.put(COLUMN_NAMA, produk.getNama_produk());
        values.put(COLUMN_MERK, produk.getMerk_produk());
        values.put(COLUMN_JENIS, produk.getJenis_produk());
        values.put(COLUMN_VARIASI, produk.getVariasi_produk());
        values.put(COLUMN_FOTO, produk.getFoto_produk());

        db.insert(TABLE_PRODUK, null, values);
        db.close();
    }

    // FUNGSI UNTUK AMBIL 1 DATA PRODUK
    public Produk getProduk(int id_produk){
        SQLiteDatabase db = this.getReadableDatabase();

        Cursor cursor = db.query(TABLE_PRODUK, new String[]{COLUMN_ID, COLUMN_KD ,COLUMN_NAMA, COLUMN_MERK
                ,COLUMN_JENIS, COLUMN_VARIASI , COLUMN_FOTO },
                COLUMN_ID + "=?", new String[]{String.valueOf(id_produk)}, null, null,null, null);
        if (cursor != null)
            cursor.moveToFirst();

        Produk produk = new Produk(cursor.getString(1), cursor.getString(2),cursor.getString(3),
                cursor.getString(4),cursor.getString(5),cursor.getString(6));
        return produk;
    }

    // FUNGSI UNTUK AMBIL SEMUA DATA PRODUK
    public List<Produk> getSemuaProduk(){
        List<Produk> produkList = new ArrayList<>();
        String selectQuery = " SELECT * FROM " + TABLE_PRODUK ;

        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);

        if (cursor.moveToFirst()){
            do {
                Produk produk = new Produk(cursor.getString(1), cursor.getString(2),cursor.getString(3),
                        cursor.getString(4),cursor.getString(5),cursor.getString(6));
                produkList.add(produk);
            } while (cursor.moveToNext());
        }
        return produkList;
    }

    // FUNGSI MENGHITUNG ADA BEBERAPA DATA
    public int getProdukCount(){
        String countQuery = "SELECT * FROM " + TABLE_PRODUK;
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(countQuery, null);
        cursor.close();
        return cursor.getCount();
    }

    // FUNGSI UPDATE DATA PRODUK
    public int updateDataProduk(Produk produk) {
        SQLiteDatabase db = this.getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(COLUMN_KD, produk.getKd_produk());
        values.put(COLUMN_NAMA, produk.getNama_produk());
        values.put(COLUMN_MERK, produk.getMerk_produk());
        values.put(COLUMN_JENIS, produk.getJenis_produk());
        values.put(COLUMN_VARIASI, produk.getVariasi_produk());
        values.put(COLUMN_FOTO, produk.getFoto_produk());

        return db.update(TABLE_PRODUK, values, COLUMN_ID + " = ?",
                new String[]{String.valueOf(produk.getId())});
    }

    // FUNGSI HAPUS DATA 1 PRODUK
    public void hapusDataProduk(Produk produk) {
        SQLiteDatabase db = this.getWritableDatabase();
        db.delete(TABLE_PRODUK, COLUMN_ID + " = ?",
                new String[]{String.valueOf(produk.getId())});
        db.close();
    }

    // FUNGSI UNTUK MENGHAPUS SEMUA DATA PRODUK
    public void hapusSemuaDataProduk(){
        SQLiteDatabase db = this.getWritableDatabase();

        db.execSQL("DELETE FROM " + TABLE_PRODUK);
    }

    //FUNGSI MENGAMBIL DATA WHERE DI ACTIVITY KATEGORY
    public List<Produk> getKategoryProduk(String mMerkProduk) {

        List<Produk> kategoriList = new ArrayList<>();
        String selectQuery = "SELECT * FROM " + TABLE_PRODUK + " WHERE " + COLUMN_MERK + " =? " ;
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery(selectQuery,new String[]{ mMerkProduk } );

        if (cursor.moveToFirst()) {
            do {
                Produk kategori = new Produk(cursor.getString(1), cursor.getString(2), cursor.getString(3),
                        cursor.getString(4), cursor.getString(5), cursor.getString(6));
                kategoriList.add(kategori);
            } while (cursor.moveToNext());
        }
        return kategoriList;
    }
}

错误如下:

01-29 14:10:25.342 370-370/ptacs.ekatalog.com.e_katalogproduk E/AndroidRuntime: FATAL EXCEPTION: main
   Process: ptacs.ekatalog.com.e_katalogproduk, PID: 370
   java.lang.RuntimeException: Unable to start activity ComponentInfo{ptacs.ekatalog.com.e_katalogproduk/ptacs.ekatalog.com.e_katalogproduk.activity.ActivityKategori}: java.lang.IllegalArgumentException: the bind value at index 1 is null
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2308)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2368)
       at android.app.ActivityThread.access$800(ActivityThread.java:144)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1285)
       at android.os.Handler.dispatchMessage(Handler.java:102)
       at android.os.Looper.loop(Looper.java:135)
       at android.app.ActivityThread.main(ActivityThread.java:5235)
       at java.lang.reflect.Method.invoke(Native Method)
       at java.lang.reflect.Method.invoke(Method.java:372)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:898)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)
    Caused by: java.lang.IllegalArgumentException: the bind value at index 1 is null
       at android.database.sqlite.SQLiteProgram.bindString(SQLiteProgram.java:164)
       at android.database.sqlite.SQLiteProgram.bindAllArgsAsStrings(SQLiteProgram.java:200)
       at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:47)
       at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1316)
       at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1255)
       at ptacs.ekatalog.com.e_katalogproduk.helper.DBHandler.getKategoryProduk(DBHandler.java:152)
       at ptacs.ekatalog.com.e_katalogproduk.activity.ActivityKategori.initRecyclerView(ActivityKategori.java:68)
       at ptacs.ekatalog.com.e_katalogproduk.activity.ActivityKategori.onCreate(ActivityKategori.java:43)
       at android.app.Activity.performCreate(Activity.java:6001)
       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2261)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2368) 
       at android.app.ActivityThread.access$800(ActivityThread.java:144) 
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1285) 
       at android.os.Handler.dispatchMessage(Handler.java:102) 
       at android.os.Looper.loop(Looper.java:135) 
       at android.app.ActivityThread.main(ActivityThread.java:5235) 
       at java.lang.reflect.Method.invoke(Native Method) 
       at java.lang.reflect.Method.invoke(Method.java:372) 
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:898) 
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693) 
01-29 14:10:25.364 370-370/? I/Process: Sending signal. PID: 370 SIG: 9

ACTIVITY_MENU

ACTIVITY_KATEGORI

最佳答案

您在初始化 mMerkProduk 之前调用 initRecyclerView();。因此，只需在 if (getIntent().getExtras() != null) {....} block 之后调用 initRecyclerView(); 即可。就像这样

    if (getIntent().getExtras() != null) {
        Bundle bundle = getIntent().getExtras();
        mMerkProduk = bundle.getString(Constant.BUNDLE_MERK_PRODUK); //MERK kategori

    //Toolbar
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    setTitle(mMerkProduk);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    dbHandler = new DBHandler(this);
    }

    initRecyclerView();
    cekDataRecyclerView();

关于java - 如何从 DbHandler 外部调用变量？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/48495941/

25 4 0
文章推荐： asp.net-mvc - ASP.NET MVC 的 Piranha CMS 路由问题
文章推荐： java - 安卓应用程序 :Overwriting file instead of appending
文章推荐： java - 下面的程序中c1和c2有什么区别，两者的声明相同吗？
文章推荐： java - 如何检查变量是否存在于sql表中，如果不存在则条件并将其插入到anylogic中的表中
行者123
个人简介

我是一名优秀的程序员,十分优秀！

滴滴打车优惠券免费领取
滴滴打车优惠券
Copyright 2021 - 2024 cfsdn All Rights Reserved 蜀ICP备2022000587号
广告合作:1813099741@qq.com 6ren.com