從SQLite數據庫生成的Android ListView不在電話屏幕上顯示（但在模擬器上顯示）

Question

我是Android的新手，目前正在設計一個應用程序，在該應用程序中，我需要在某個時候顯示鳥類列表。 為此，我將數據存儲在SQLite數據庫中。

因此，在某個時候，我單擊一個ListView項，該項將啟動一個新活動，該活動應該顯示我需要的鳥的列表。 問題是，當我從Android Studio中的模擬器運行該應用程序時，顯示的鳥ListView很好，但是當我嘗試從手機運行它時，則不顯示ListView，僅顯示活動的標題，其余的屏幕保持空白。 我應該提到的是，在從模擬器運行應用程序之前，我使用ADB和Android設備監視器將數據庫放入模擬器的文件系統中，只是我不知道要在何時將數據庫傳輸到手機上我需要做什么。從手機上運行該應用程序 。

MenuOiseaux.java，我要在其中顯示鳥類列表的活動：

package com.example.ant.kits;

import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import java.util.ArrayList;
import java.util.HashMap;

public class MenuOiseaux extends AppCompatActivity
{

    ListView vue;
    private SQLiteDatabase db;
    DBOpenHelper dbOpenHelper;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.list_view);
        dbOpenHelper = new DBOpenHelper(this, DBOpenHelper.Constants.DATABASE_NAME, null,
                DBOpenHelper.Constants.DATABASE_VERSION);
        db = dbOpenHelper.getWritableDatabase();

        Cursor cursor = db.rawQuery("SELECT " + DBOpenHelper.Constants.KEY_COL_ID
                + " , " + DBOpenHelper.Constants.KEY_COL_MINIATURE
                + " , " + DBOpenHelper.Constants.KEY_COL_NOM
                + " FROM " + DBOpenHelper.Constants.MY_TABLE ,null);

        ArrayList<HashMap<String, Object>> liste = new ArrayList<>();
        HashMap<String, Object> element;
        while (cursor.moveToNext())
        {
            byte[] byteArray = cursor.getBlob(1);
            Bitmap bmp = BitmapFactory.decodeByteArray(byteArray,0,byteArray.length);
            if(bmp == null){db.close();}
            element = new HashMap<>();
            element.put("miniature", bmp);
            element.put("nom",cursor.getString(2)); 
            liste.add(element);
        }
        cursor.close();
        vue = (ListView) findViewById(R.id.listView);
        SimpleAdapter adapter = new SimpleAdapter(this,
                liste,
                R.layout.list_item,
                new String[] {"miniature","nom"},
                new int[] {R.id.img,R.id.txt});
        adapter.setViewBinder(new MyViewBinder());
        vue.setAdapter(adapter);

        vue.setOnItemClickListener(new ListView.OnItemClickListener()
        {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position, long id)
            {
                Cursor cursor = db.rawQuery("SELECT " + DBOpenHelper.Constants.KEY_COL_ID
                        + " , " + DBOpenHelper.Constants.KEY_COL_NOM
                        + " , " + DBOpenHelper.Constants.KEY_COL_PHOTO
                        + " , " + DBOpenHelper.Constants.KEY_COL_DESCRIPTION
                        + " FROM " + DBOpenHelper.Constants.MY_TABLE
                        + " WHERE " + DBOpenHelper.Constants.KEY_COL_ID + " = " + String.valueOf(position+1),null);

                cursor.moveToFirst();
                Intent intent = new Intent(MenuOiseaux.this, FicheBiodiv.class);
                intent.putExtra("Nom", cursor.getString(1));
                byte[] byteArray = cursor.getBlob(2);
                Bitmap bmp = BitmapFactory.decodeByteArray(byteArray, 0 ,byteArray.length);
                intent.putExtra("BitmapImage", bmp);
                intent.putExtra("Description", cursor.getString(3));
                startActivity(intent);
            }
        });
    }
}

DBOpenHelper.java，用於創建數據庫（？）：

package com.example.ant.kits;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.provider.BaseColumns;


public class DBOpenHelper extends SQLiteOpenHelper
{
    public static class Constants implements BaseColumns
    {
        public static final String DATABASE_NAME = "animaux.db";
        public static final int DATABASE_VERSION = 1;
        public static final String MY_TABLE = "Animaux";
        public static final String KEY_COL_ID = "_id";
        public static final String KEY_COL_MINIATURE = "miniature";
        public static final String KEY_COL_NOM = "nom";
        public static final String KEY_COL_DESCRIPTION = "description";
        public static final String KEY_COL_PHOTO = "photo";
        public static final int ID_COL = 1;
        public static final int NOM_COL = 2;
        public static final int DESCRIPTION_COL = 3;
        public static final int PHOTO_COL = 4;
    }

    private static final String DATABASE_CREATE = "CREATE TABLE " + Constants.MY_TABLE + " ( "
            + Constants.KEY_COL_ID + " integer primary key autoincrement, "
            + Constants.KEY_COL_MINIATURE + " BLOB , "
            + Constants.KEY_COL_NOM + " TEXT , "
            + Constants.KEY_COL_DESCRIPTION + " TEXT ,"
            + Constants.KEY_COL_PHOTO + " BLOB )";
    public static final String METIER_TABLE_DROP = " DROP TABLE IF EXISTS " + Constants.MY_TABLE + " ;";

    public DBOpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version)
    {
        super(context, name, factory, version);
    }

    @Override
    public void onCreate(SQLiteDatabase db)
    {
        db.execSQL(DATABASE_CREATE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
    {
        db.execSQL(METIER_TABLE_DROP);
        onCreate(db);
    }
}

抱歉，如果我不清楚，請先感謝您的幫助！

Answer 1

您沒有在設備上得到任何列表，因為您的數據庫為空。 嘗試通過代碼向表中添加一些條目。 它應該工作。

您應該閱讀以下答案以復制數據庫：

https://stackoverflow.com/a/29733700/5671534