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Android如何在两个不同的活动中保存和显示数据

androidsqlite
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我正在进行一个Android项目，其中包含大学列表，点击该列表会显示大学详情。
以下是快照：
- 学校列表 - 学校详情 在学校详情的右上方工具栏中，我设置了一个小星形图标。单击该图标后，图标变为填充图标，并将该学校的名称保存到书签类中，以列表的形式显示。现在我希望也能存储详细信息。我的意思是，在单击已加书签的列表项时，我想存储并显示详细信息，就像SchoolDetails类一样。我想知道如何使用SQLite数据库来实现。请指导我如何做。
这是我的书签类。
public class Bookmark extends AppCompatActivity {
    private List<Bookmarkitem> ourBookmarkListItems = new ArrayList<Bookmarkitem>();
    private ListView listView;
    private BookmarkAdapter adapter;
    DatabaseHelper dbhelper;
    private Toolbar toolbar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_bookmark);
        dbhelper = new DatabaseHelper(this);

        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        toolbar.setPadding(0, getStatusBarHeight(), 0, 0);

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setTitle("Bookmark");

        List<Bookmarkitem> bookmarkedSchools = dbhelper.getAllSchoolBookmark();

        listView = (ListView) findViewById(R.id.list_bookmarked);
        if (bookmarkedSchools.size() != 0) {
            adapter = new BookmarkAdapter(this, bookmarkedSchools);
            listView.setAdapter(adapter);
        } else {
            Toast.makeText(this, "You have no bookmark yet.", Toast.LENGTH_SHORT).show();
        }

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                Intent i = new Intent(Bookmark.this, SchoolDetails.class);

                startActivity(i);

            }
        });


    }

这是我的数据库类，现在只存储学校的名称、标志和地址。

      package com.example.user.educationhunt.database;

import android.accessibilityservice.GestureDescription;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.view.MenuItem;

import com.example.user.educationhunt.listner.DatabaseUpdatedListener;
import com.example.user.educationhunt.pojos.Bookmarkitem;

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

/**
 * Created by user on 11/22/2016.
 */
public class DatabaseHelper extends SQLiteOpenHelper {

    public DatabaseUpdatedListener databaseUpdatedListener;
    static final String DATABASE_NAME = "BookmarkDatabase";
    private static final int DATABASE_VERSION = 1;
    private static final String TABLE_NAME_BOOKMARK = "bookmark";

    //    Contact table columns name
    private static final String ID = "Id";
    private static final String SID = "SId";
    private static final String NAME = "Name";
    private static final String LOGO = "Logo";
    private static final String LOCATION = "Location";

    String createTableBookmark = "Create table if not exists `Bookmark` ("
            + "`name`   TEXT," + "`location`    TEXT," + "`logo`    TEXT);";

    String CREATE_SCHOOL_BOOKMARK_TABLE = "CREATE TABLE " + TABLE_NAME_BOOKMARK + "("
            + ID + " INTEGER PRIMARY KEY, "
            + SID + " INTEGER, "
            + NAME + " TEXT, "
            + LOGO + " TEXT, "
            + LOCATION + " TEXT " + ")";

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    public void insertBookmarkData(Bookmarkitem bookmarkitem) {
        SQLiteDatabase db = getWritableDatabase();
        ContentValues content = new ContentValues();
        content.put("name", bookmarkitem.name);
        content.put("location", bookmarkitem.address);
        content.put("logo", bookmarkitem.logo);

        db.insert("Bookmark", null, content);
    }

    public ArrayList<Bookmarkitem> getBookmarkist() {
        String sql = "select * from Bookmark ";
        ArrayList<Bookmarkitem> bookmarklist = new ArrayList<Bookmarkitem>();

        Cursor c = getWritableDatabase().rawQuery(sql, null);
        while (c.moveToNext()) {
            Bookmarkitem info = new Bookmarkitem();
            info.name = c.getString(c.getColumnIndex("name"));
            info.address = c.getString(c.getColumnIndex("location"));
            info.logo = c.getString(c.getColumnIndex("logo"));
            bookmarklist.add(info);
        }
        c.close();
        return bookmarklist;
    }

    public Bookmarkitem getBookmarkData(String bookmarkName) {
        String sql = "select * from Bookmark  where id='" + bookmarkName + "'";

        Cursor c = getWritableDatabase().rawQuery(sql, null);
        while (c.moveToNext()) {
            Bookmarkitem info = new Bookmarkitem();
            info.name = c.getString(c.getColumnIndex("name"));
            info.address = c.getString(c.getColumnIndex("location"));
            info.logo = c.getString(c.getColumnIndex("logo"));
        }
        c.close();
        Bookmarkitem info = null;
        return info;
    }

    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        // TODO Auto-generated method stub
        sqLiteDatabase.execSQL(CREATE_SCHOOL_BOOKMARK_TABLE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int arg1, int arg2) {
        // TODO Auto-generated method stub
        sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME_BOOKMARK);
        onCreate(sqLiteDatabase);
    }

    public void addSchoolBookmark(Bookmarkitem bookmarkitem, MenuItem menuItem) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(SID, bookmarkitem.getBookmarkID());
        values.put(NAME, bookmarkitem.getName());
        values.put(LOGO, bookmarkitem.getLogo());
        values.put(LOCATION, bookmarkitem.getAddress());

        //inserting row
        if (db.insert(TABLE_NAME_BOOKMARK, null, values) != -1) {
            databaseUpdatedListener.setDatabaseSuccess(bookmarkitem.getName(), menuItem);
        } else {
            databaseUpdatedListener.setDatabaseError("Failed to insert");
        }
        db.close();
    }

    public List<Bookmarkitem> getAllSchoolBookmark() {
        SQLiteDatabase db = this.getWritableDatabase();
        String selectQuery = "SELECT * FROM " + TABLE_NAME_BOOKMARK;
        List<Bookmarkitem> bookmarkitems = new ArrayList<>();
        Cursor cursor = db.rawQuery(selectQuery, null);

        if (cursor.moveToFirst()) {
            do {
                Bookmarkitem bookmarkitem = new Bookmarkitem();
                bookmarkitem.setBookmarkID(Integer.parseInt(cursor.getString(0)));
                bookmarkitem.setName(cursor.getString(1));
                bookmarkitem.setLogo(cursor.getString(2));
                bookmarkitem.setAddress(cursor.getString(3));
                bookmarkitems.add(bookmarkitem);
            } while (cursor.moveToNext());
        }
        return bookmarkitems;
    }

    public void removeBookmarkItem(int sID) {
        SQLiteDatabase db = this.getWritableDatabase();
        db.execSQL("DELETE FROM " + TABLE_NAME_BOOKMARK + " WHERE " + SID+ "= '" + sID+ "'");
        db.close();


    }
}

这是我的SchoolDetails类

package com.example.user.educationhunt;

import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;

import com.example.user.educationhunt.database.DatabaseHelper;
import com.example.user.educationhunt.fragment.About;
import com.example.user.educationhunt.fragment.Admission;
import com.example.user.educationhunt.fragment.FeeStructure;
import com.example.user.educationhunt.listner.DatabaseUpdatedListener;
import com.example.user.educationhunt.pojos.Bookmarkitem;
import com.example.user.educationhunt.pojos.OurSchool;

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

public class SchoolDetails extends AppCompatActivity implements DatabaseUpdatedListener {

    private Toolbar toolbar;
    private TabLayout tabLayout;
    private ViewPager viewPager;
    Boolean isStarFilled = false;
    DatabaseHelper db;
    OurSchool ourSchool;
    private Menu menu;


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

        ourSchool = (OurSchool) getIntent().getSerializableExtra("school");

        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setTitle(ourSchool.getSchoolName());


        db = new DatabaseHelper(this);
        db.databaseUpdatedListener = this;

        Toast.makeText(this, ourSchool.getSchoolName(), Toast.LENGTH_SHORT).show();

        viewPager = (ViewPager) findViewById(R.id.viewpager);
        setupViewPager(viewPager);

        tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(viewPager);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.fav_school, menu);
        this.menu = menu;
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.star_School:
                Bookmarkitem bookmarkitem = new Bookmarkitem();
                bookmarkitem.setBookmarkID(ourSchool.getSchoolId());
                bookmarkitem.setName(ourSchool.getSchoolName());
                bookmarkitem.setLogo(ourSchool.getSchoolLogo());
                bookmarkitem.setAddress(ourSchool.getSchoolAddress());
                db.addSchoolBookmark(bookmarkitem, item);
                return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        List<Bookmarkitem> bookmarkitems = db.getAllSchoolBookmark();
        if (bookmarkitems.size() != 0) {
            for (Bookmarkitem bookmarkitem : bookmarkitems) {
                if (bookmarkitem.getBookmarkID() == ourSchool.getSchoolId()) {
                    isStarFilled = true;
                    break;
                }
                else isStarFilled=false;
            }
            if (isStarFilled) {
                menu.getItem(0).setIcon(getResources().getDrawable(R.mipmap.starfilled));
            }else if (isStarFilled.booleanValue()==true){
                delete();
                menu.getItem(0).setIcon(getResources().getDrawable(R.mipmap.star));
            }
        }
        return true;
    }

    public void delete(){
        List<Bookmarkitem> bookmarkitems = db.getAllSchoolBookmark();
        db.removeBookmarkItem(ourSchool.getSchoolId());    }

    private void setupViewPager(ViewPager viewPager) {
        ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
        adapter.addFragment(new About(), "ABOUT US");
        adapter.addFragment(new Admission(), "ADMISSION");
        adapter.addFragment(new FeeStructure(), "FEE");
        viewPager.setAdapter(adapter);
    }


    @Override
    public void setDatabaseSuccess(String schoolName, MenuItem item) {
        Toast.makeText(this, schoolName + "successfully added as bookmark", Toast.LENGTH_SHORT).show();
        item.setIcon(R.mipmap.starfilled);
    }

    @Override
    public void setDatabaseError(String failureMessage) {
        Toast.makeText(this, failureMessage, Toast.LENGTH_SHORT).show();
    }

    class ViewPagerAdapter extends FragmentPagerAdapter {
        private final List<Fragment> mFragmentList = new ArrayList<>();
        private final List<String> mFragmentTitleList = new ArrayList<>();

        public ViewPagerAdapter(FragmentManager manager) {
            super(manager);
        }

        @Override
        public Fragment getItem(int position) {
            return mFragmentList.get(position);
        }

        @Override
        public int getCount() {
            return mFragmentList.size();
        }

        public void addFragment(Fragment fragment, String title) {
            mFragmentList.add(fragment);
            mFragmentTitleList.add(title);
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return mFragmentTitleList.get(position);
        }
    }
}

任何建议都将受到热烈欢迎。
在你的SQLite数据库中，使用相同的ID保存学校详细信息。然后再次获取相同ID的数据并显示它。 - Divyesh Patel
我需要创建一个不同的数据库还是可以在同一个数据库中添加详细信息字段？ - Edward Mintus
只需在同一数据库中创建新表即可。 - Divyesh Patel
Divyesh兄弟，感谢您的建议，您能帮我删除已加书签的项目吗？我的意思是当我点击书签图标时，应该从书签列表中删除已加书签的项目。 - Edward Mintus
当您单击书签图标时，获取您的项目位置，并从该位置获取学校ID。现在，在您的收藏夹列表中检查该ID并将其从列表中删除。 - Divyesh Patel
显示剩余5条评论
1个回答
1
private static final int ID = "Id";
private static final int SID = "SId";
private static final String NAME = "Name";
private static final String LOGO = "Logo";
private static final String LOCATION = "Location";

更改创建表的代码：

  String CREATE_SCHOOL_BOOKMARK_TABLE = "CREATE TABLE " + TABLE_NAME_BOOKMARK + "("
                + ID + " INTEGER PRIMARY KEY, "
                + SID + " INTEGER, "
                + NAME + " TEXT, "
                + LOGO + " TEXT, "
                + LOCATION + " TEXT " + ")";

同时更改此处：

public void addSchoolBookmark(Bookmarkitem bookmarkitem, MenuItem menuItem) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(SID, bookmarkitem.getBookmarkID());
        values.put(NAME, bookmarkitem.getName());
        values.put(LOGO, bookmarkitem.getLogo());
        values.put(LOCATION, bookmarkitem.getAddress());

        //inserting row
        if (db.insert(TABLE_NAME_BOOKMARK, null, values) != -1) {
            databaseUpdatedListener.setDatabaseSuccess(bookmarkitem.getName(), menuItem);
        } else {
            databaseUpdatedListener.setDatabaseError("Failed to insert");
        }
        db.close();
    }

首先在SCHOOL类中创建一个方法，用于从书签表中删除条目：

            db.removeBookmarkItem(ourSchool.getSchoolId(), item);

现在，在数据库类中：实现上述方法以删除记录：
public void removeBookmarkItem(int sID) {
    SQLiteDatabase db = this.getWritableDatabase();



   database.execSQL("DELETE FROM " + TABLE_NAME + " WHERE " + SID+ "= '" + sID+ "'");
db.close();


}

在这两种情况下都使用相同的方法，您需要检查项目是否已被标记为书签，然后将该ID发送到删除方法中，即可删除数据。

当您从该ID中删除记录时会发生什么？ - Divyesh Patel
没有任何更改，你检查了我上面的代码吗？我可能搞砸了。请看一下。 - Edward Mintus
你的书签表中没有插入学校ID，请将删除方法更改为我上面更新的内容。 - Divyesh Patel
亲爱的先生，在数据库类中的removeBookmarkItem方法中，您只包含了一个参数，但在School类中的函数调用期间，您包含了2个参数。这会导致我的第二个参数“item”出现错误。当我从代码中删除该项时，它不显示任何错误，但在运行应用程序时没有任何更改，就像上面一样。 - Edward Mintus
兄弟，按照你的建议，结果变得更糟了，现在我甚至无法将我的数据保存到列表中。 - Edward Mintus
显示剩余3条评论
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