收藏时会判断失误，然后出现重复收藏的情况

首次点击收藏时运行良好，再次点击时也能判断出已收藏。但是在上下页翻动后，判断是否收藏的机制出现异常。之后任意一篇点击收藏后再次点击收藏也能再次收藏，甚至是同篇的多次收藏。

MainActivity.java package com.example.self_application_homework.activity; import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.ImageView;相关截图： import android.widget.TextView; import android.widget.Toast; import com.example.self_application_homework.R; import com.example.self_application_homework.bean.Article; import com.example.self_application_homework.biz.ArticleBiz; import com.example.self_application_homework.dao.ArticleDao; import com.example.self_application_homework.dao.ArticleDbHelper; import com.example.self_application_homework.utils.ImageLoader; import java.io.Serializable; import java.util.ArrayList; import java.util.List; public class MainActivity extends AppCompatActivity {  private Button mBtnDeleteDb;  private Button mBtnLastOne, mBtnCollect, mBtnNextOne;  private TextView mTvMyfavourites, mTvTitle, mTvAuthor, mTvContent;  private ImageView mIvAdvertise; 

// for advertisement bitmap<br>    private ImageLoader imageLoader;<br><br>    // for current page article<br>    int currentPage = 1;<br>    private ArticleBiz mArticleBiz = new ArticleBiz();<br>    private ArticleDao mArticleDao = new ArticleDao();<br>    private Article article = new Article();<br><br>    // for MyFavourites<br>    Intent itToMyFavourites = null;<br>    List<Article> articleList = new ArrayList<>();<br><br>    private static final String TAG = "MainActivity -app";<br><br>    @Override<br>    protected void onCreate(Bundle savedInstanceState) {<br>        super.onCreate(savedInstanceState);<br>        setContentView(R.layout.activity_main);<br><br>        initViewsNDatas();<br><br>        loadAdvertisement();<br><br>        loadDatas(currentPage, false);<br>    }<br><br>    private void initViewsNDatas() {<br>        mBtnLastOne = findViewById(R.id.id_btn_lastOne);<br>        mBtnCollect = findViewById(R.id.id_btn_collect);<br>        mBtnNextOne = findViewById(R.id.id_btn_nextOne);<br>        mTvMyfavourites = findViewById(R.id.id_tv_myFavourites);<br>        mTvTitle = findViewById(R.id.id_tv_title);<br>        mTvAuthor = findViewById(R.id.id_tv_author);<br>        mTvContent = findViewById(R.id.id_tv_content);<br>        mIvAdvertise = findViewById(R.id.id_iv_advertise);<br><br>        itToMyFavourites = new Intent(MainActivity.this, MyFavouritesActivity.class);<br><br>        mBtnDeleteDb = findViewById(R.id.id_btn_deleteDb);<br>    }<br><br>    public void initEvenets(View v) {<br>        switch (v.getId()) {<br>            case R.id.id_tv_myFavourites:<br>                // 打开收藏页面<br>                if (mArticleDao.loadFromDb(this).isEmpty())<br>                    Toast.makeText(this, "还没收藏任何内容", Toast.LENGTH_SHORT).show();<br>                else<br>                    startActivity(itToMyFavourites);<br>                break;<br>            case R.id.id_btn_lastOne:<br>                // 打开上一页<br>                Log.d(TAG, "currentPage: " + currentPage);<br>                loadDatas(loadPage(false), true);<br>                break;<br>            case R.id.id_btn_collect:<br>                // 点击收藏按钮<br>                List<Article> articleList = mArticleDao.loadFromDb(this);<br><br>                // 先判断收藏里（数据库）是否为空，为空直接添加数据，不为空则进一步判断<br>                if (articleList.isEmpty() || articleList == null) {<br>                    mArticleDao.insertToDb(this, article);<br>                    Toast.makeText(this, "收藏成功", Toast.LENGTH_SHORT).show();<br>                    Log.d(TAG, "articleList.isEmpty(): " + articleList.isEmpty());<br>                } else {<br>                    // 收藏中有相同的文章则跳过，否则添加巾数据库<br>                    for (Article articleInLoop : articleList) {<br>                        Log.d(TAG, "article.getTitle().equals(articleInLoop.getTitle()): " + article.getTitle().equals(articleInLoop.getTitle()));<br>                        if (article.getTitle().equals(articleInLoop.getTitle())) {<br>                            Toast.makeText(this, "此文章已收藏", Toast.LENGTH_SHORT).show();<br>                        } else {<br>                            mArticleDao.insertToDb(this, article);<br>                            Toast.makeText(this, "收藏成功", Toast.LENGTH_SHORT).show();<br>                        }<br>                    }<br>                }<br>                break;<br>            case R.id.id_btn_nextOne:<br>                // 打开下一页<br>                loadDatas(loadPage(true), true);<br>                break;<br>            case R.id.id_btn_deleteDb:<br>                // 删库<br>                mArticleDao.deleteDb(this);<br>                Toast.makeText(this, "数据库已清空", Toast.LENGTH_SHORT).show();<br>                break;<br>        }<br>    }<br><br>    private void loadAdvertisement() {<br>        imageLoader = new ImageLoader();<br>        int random = (int) (3 * Math.random() + 1);<br>        imageLoader.loadImageByAsynTask(mIvAdvertise, "http://www.imooc.com/api/teacher?type=1", random);<br>    }<br><br>    private void loadDatas(int page, boolean isUseCache) {<br>        mArticleBiz.loadDatas(new ArticleBiz.Callback() {<br>            @Override<br>            public void onSuccess(Article resultArticle) {<br>                article = resultArticle;<br>                mTvTitle.setText(article.getTitle());<br>                mTvAuthor.setText(article.getAuthor());<br>                mTvContent.setText(article.getContent());<br>            }<br><br>            @Override<br>            public void onFailure(Exception ex) {<br>                ex.printStackTrace();<br>            }<br>        }, page, isUseCache);<br>    }<br><br>    private int loadPage(boolean nextPage) {<br>        if (nextPage == true)<br>            currentPage++;<br>        else<br>            currentPage--;<br><br>        if (currentPage < 1)<br>            currentPage = 30;<br>        if (currentPage > 30)<br>            currentPage = 1;<br><br>        return currentPage;<br>    }<br><br>}<br>

ArticleDao.java package com.example.self_application_homework.dao; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import androidx.annotation.NonNull; import com.example.self_application_homework.bean.Article; import java.util.ArrayList; import java.util.List; public class ArticleDao {  public List<Article> loadFromDb(@NonNull

Context context) {<br><br>        ArticleDbHelper dbHelper = ArticleDbHelper.getInstance(context);<br>        SQLiteDatabase db = dbHelper.getWritableDatabase();<br><br>        List<Article> articleList =

new ArrayList<>(); Cursor cursor = db.rawQuery("SELECT * FROM " + Article.TABLE_NAME, null); Article article = null;  while (cursor.moveToNext()) {  int

id = cursor.getInt(cursor.getColumnIndex(Article.COL_ID));<br>            String title = cursor.getString(cursor.getColumnIndex(Article.COL_TITLE));<br>            String author = cursor.getString(cursor.getColumnIndex(Article.COL_AUTHOR));<br>            String content = cursor.getString(cursor.getColumnIndex(Article.COL_CONTENT));<br>            article =

new

Article(title, author, content);<br>            articleList.add(article);<br>        }<br>        cursor.close();<br><br>

return articleList; }  public void insertToDb(@NonNull Context context, Article article) {  if (article == null) {  return

;<br>        }<br><br>        ArticleDbHelper dbHelper = ArticleDbHelper.getInstance(context);<br>        SQLiteDatabase db = dbHelper.getWritableDatabase();<br><br>        db.beginTransaction();<br><br>        ContentValues contentValues =

null; contentValues = new

ContentValues();<br>        contentValues.put(Article.COL_TITLE, article.getTitle());<br>        contentValues.put(Article.COL_AUTHOR, article.getContent());<br>        contentValues.put(Article.COL_CONTENT, article.getAuthor());<br>        db.insertWithOnConflict(Article.TABLE_NAME,

null

, contentValues, SQLiteDatabase.CONFLICT_REPLACE);<br><br>        db.setTransactionSuccessful();<br>        db.endTransaction();<br>    }<br><br>

public void deleteDb(@NonNull

Context context) {<br>        ArticleDbHelper dbHelper = ArticleDbHelper.getInstance(context);<br>        SQLiteDatabase db = dbHelper.getWritableDatabase();<br>        db.execSQL(

"DELETE FROM " + Article.TABLE_NAME); } } 