android - 当我尝试使用 onItemClickListener 将数据传递给另一个 Activity 时，没有从 sqlite 获取数据

Question

我试图在 OnItemClickListener 的 RecyclerView 中将 ID 从 SQLite 从一个 Activity 传递到另一个 Activity ，但我没有在接收 Activity 中获取数据。

这是我发送数据的 Activity (已编辑):

    public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    public final static String KEY_EXTRA_BIRTHDAY_ID = "KEY_EXTRA_BIRTHDAY_ID";

    RecyclerView mRecyclerView;
    RecyclerView.LayoutManager mLayoutManager;
    GridAdapter mGridAdapter;
    DBHelper dbh;
    String firstName;
    Animation shakeAnimation;
    ImageView deleteImage;
    List<Birthday> birthdays;
    int birthdayId;

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

        initAddImage();
        dbh = new DBHelper(this);

        initRecyclerView();
        initDeleteImage();

    }

    public List<Birthday> getData() {
        birthdays = new ArrayList<>();
        Birthday birthday = null;
        Cursor c = dbh.getBirthdayData();
        if (c != null) {
            while (c.moveToNext()) {
                int nameIndex = c.getColumnIndex(dbh.BIRTHDAY_NAME);
                String nameText = c.getString(nameIndex);
                this.firstName = nameText;

                int lastNameIndex = c.getColumnIndex(dbh.BIRTHDAY_LAST_NAME);
                String lastNameText = c.getString(lastNameIndex);

                int birthdayIdIndex = c.getColumnIndex(dbh.BIRTHDAY_ID);
                birthdayId = c.getInt(birthdayIdIndex);

                birthday = new Birthday();
                birthday.setBIRTHDAY_ID(birthdayId);
                birthday.setNAME(nameText);
                birthday.setLAST_NAME(lastNameText);
                birthdays.add(birthday);

            }
        }
        return birthdays;
    }

    private void initRecyclerView(){
        mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        mRecyclerView.setItemAnimator(new ScaleInAnimator());

        // The number of Columns
        mRecyclerView.setHasFixedSize(true);
        mLayoutManager = new GridLayoutManager(this, 3);
        mRecyclerView.setLayoutManager(mLayoutManager);

        mGridAdapter = new GridAdapter(getData());

        mRecyclerView.setAdapter(mGridAdapter);
        mGridAdapter.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {
                Toast.makeText(MainActivity.this, "It works!", Toast.LENGTH_SHORT).show();
//                Cursor cursorItem = dbh.getBirthdayId(position);
//                if( cursorItem != null && cursorItem.moveToFirst() ){
//                    birthdayId = cursorItem.getInt(cursorItem.getColumnIndex(DBHelper.BIRTHDAY_ID));
//                    cursorItem.close();
//                }
                Intent intent = new Intent(MainActivity.this, EditBirthdayActivity.class);
                intent.putExtra(KEY_EXTRA_BIRTHDAY_ID, birthdayId);
                startActivity(intent);
            }
        });
    }

    private void initAddImage(){
        ImageView addImage = (ImageView) findViewById(R.id.add_image);
        addImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, AddBirthday.class);
                startActivity(intent);
            }
        });
    }

    private void initDeleteImage(){
        deleteImage = (ImageView) findViewById(R.id.delete_image);
        shakeAnimation = AnimationUtils.loadAnimation(MainActivity.this, R.anim.shake_animation);
        deleteImage.setOnClickListener(this);
    }

    @Override
    protected void onResume() {
        super.onResume();
        initRecyclerView();
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.delete_image:
                mRecyclerView.startAnimation(shakeAnimation);
                if (v.equals(deleteImage)) {
                    mGridAdapter.setOnItemClickListener(new OnItemClickListener() {
                        @Override
                        public void onItemClick(View view, int position) {
                            dbh.deleteBirthday(position);
                            mGridAdapter.removeItem(position);
                            mRecyclerView.clearAnimation();
                        }
                    });
                }
        }
    }
} super.onResume();
            initRecyclerView();
        }

        @Override
        public void onClick(View v) {
            switch (v.getId()){
                case R.id.delete_image:
                    mRecyclerView.startAnimation(shakeAnimation);
                    if (v.equals(deleteImage)) {
                        mGridAdapter.setOnItemClickListener(new OnItemClickListener() {
                            @Override
                            public void onItemClick(View view, int position) {
                                dbh.deleteBirthday(position);
                                mGridAdapter.removeItem(position);
                                mRecyclerView.clearAnimation();
                            }
                        });
                    }
            }
        }
    }

这是接收者 Activity :

    public class EditBirthdayActivity extends AppCompatActivity implements View.OnClickListener {

    private DBHelper dbh;
    EditText inputFirstName;
    EditText inputLastName;

    Button saveButton;
    Button editButton, deleteButton;

    int birthdayId;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        birthdayId = getIntent().getIntExtra(MainActivity.KEY_EXTRA_BIRTHDAY_ID, 0);

        setContentView(R.layout.edit_birthday);

        dbh = new DBHelper(this);
        init();

        if (birthdayId > 0) {

            saveButton.setVisibility(View.GONE);
            editButton.setVisibility(View.VISIBLE);
            deleteButton.setVisibility(View.VISIBLE);

            Cursor rs = dbh.getBirthdayId(birthdayId);
            rs.moveToFirst();

            String getName = rs.getString(rs.getColumnIndex(DBHelper.BIRTHDAY_NAME));
            String getLastName = rs.getString(rs.getColumnIndex(DBHelper.BIRTHDAY_LAST_NAME));

            if (!rs.isClosed()) {
                rs.close();
            }

            inputFirstName.setText(getName);
            inputFirstName.setFocusable(false);
            inputFirstName.setClickable(false);
            inputLastName.setText(getLastName);
            inputLastName.setFocusable(false);
            inputLastName.setClickable(false);

        }
    }

    private void init(){
        inputFirstName = (EditText) findViewById(R.id.input_first_name);
        inputLastName = (EditText) findViewById(R.id.input_last_name);

        saveButton = (Button) findViewById(R.id.save_button);
        editButton = (Button) findViewById(R.id.edit_button);
        deleteButton = (Button) findViewById(R.id.delete_button);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.save_button:
                saveBirthday();
                return;
            case R.id.edit_button:
                saveButton.setVisibility(View.VISIBLE);
                editButton.setVisibility(View.GONE);
                deleteButton.setVisibility(View.GONE);
                inputFirstName.setEnabled(true);
                inputFirstName.setFocusableInTouchMode(true);
                inputFirstName.setClickable(true);

                inputLastName.setEnabled(true);
                inputLastName.setFocusableInTouchMode(true);
                inputLastName.setClickable(true);
                return;
            case R.id.delete_button:
                AlertDialog.Builder builder = new AlertDialog.Builder(EditBirthdayActivity.this);
                builder.setMessage(R.string.delete_message)
                        .setPositiveButton(R.string.yes, new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                dbh.deleteBirthday(birthdayId);
                                Toast.makeText(EditBirthdayActivity.this, "Deleted Successfully", Toast.LENGTH_SHORT).show();
                                Intent intent = new Intent(EditBirthdayActivity.this, MainActivity.class);
                                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                                startActivity(intent);
                            }
                        })
                        .setNegativeButton(R.string.no, new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                // User cancelled the dialog..
                            }
                        });
                AlertDialog d = builder.create();
                d.setTitle(R.string.delete_title);
                d.show();
                return;
        }
    }

    public void saveBirthday(){
        String getName, getLastName;
        getName = inputFirstName.getText().toString();
        getLastName = inputLastName.getText().toString();
        if (birthdayId > 0) {
            if (dbh.updateBirthday(birthdayId, inputFirstName.getText().toString(),
                    inputLastName.getText().toString())) {
                Toast.makeText(EditBirthdayActivity.this, "Updated Successfully", Toast.LENGTH_SHORT).show();
                Intent intent = new Intent(EditBirthdayActivity.this, MainActivity.class);
                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(intent);
            } else {
                Toast.makeText(EditBirthdayActivity.this, "Update Failed", Toast.LENGTH_SHORT).show();
            }
        } else {
            if (dbh.insertBirthday(getName, getLastName)){
                Toast.makeText(EditBirthdayActivity.this, "Birthday Inserted!", Toast.LENGTH_SHORT).show();
            } else  {
                Toast.makeText(EditBirthdayActivity.this, "Couldn't insert Birthday!", Toast.LENGTH_SHORT).show();
            }
            Intent intent = new Intent(EditBirthdayActivity.this, MainActivity.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(intent);
        }
    }
}

编辑:(数据库类)

public class DBHelper extends SQLiteOpenHelper {

private static final int DATABASE_VERSION = 2;
private static final String DATABASE_NAME = "_database";

private static final String BIRTHDAY_TABLE_NAME = "birthday_table";
public static final String BIRTHDAY_ID = "birthday_id";
public static final String BIRTHDAY_NAME = "birthday_name";
public static final String BIRTHDAY_LAST_NAME = "birthday_last_name";

private static final String CREATE_TABLE = "CREATE TABLE " + BIRTHDAY_TABLE_NAME + " ( "
        + BIRTHDAY_ID + " INTEGER PRIMARY KEY,"
        + BIRTHDAY_NAME + " TEXT,"
        + BIRTHDAY_LAST_NAME + " TEXT );";

SQLiteDatabase database;

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

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

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS " + BIRTHDAY_TABLE_NAME);
    onCreate(db);
}

public void setBirthdayData(String birthdayName, String birthdayLastName) {
    database = getWritableDatabase();
    ContentValues cv = new ContentValues();
    cv.put(BIRTHDAY_NAME, birthdayName);
    cv.put(BIRTHDAY_LAST_NAME, birthdayLastName);
    database.insert(BIRTHDAY_TABLE_NAME, null, cv);
}

public boolean insertBirthday(String birthdayName, String birthdayLastName) {
    SQLiteDatabase db = getWritableDatabase();
    ContentValues contentValues = new ContentValues();
    contentValues.put(BIRTHDAY_NAME, birthdayName);
    contentValues.put(BIRTHDAY_LAST_NAME, birthdayLastName);
    db.insert(BIRTHDAY_TABLE_NAME, null, contentValues);
    return true;
}

public Cursor getBirthdayId(int id){
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor res = db.rawQuery("SELECT * FROM " + BIRTHDAY_TABLE_NAME + " WHERE " +
            BIRTHDAY_ID + "=?", new String[] { Integer.toString(id) } );
    return res;
}

public Cursor getBirthdayData() {
    database = getReadableDatabase();
    String[] columns = {BIRTHDAY_ID, BIRTHDAY_NAME, BIRTHDAY_LAST_NAME};
    Cursor c = database.query(BIRTHDAY_TABLE_NAME, columns, null, null, null, null, BIRTHDAY_ID + " DESC");
    return c;
}

public Cursor getBirthdayName(String[] args) {
    database = getReadableDatabase();
    String query = "SELECT " + BIRTHDAY_NAME + " FROM " + BIRTHDAY_TABLE_NAME + " WHERE " + BIRTHDAY_NAME + " =?";
    Cursor c = database.rawQuery(query, args);
    return c;
}

public boolean updateBirthday(Integer id, String birthdayName, String birthdayLastName) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues cv = new ContentValues();
    cv.put(BIRTHDAY_NAME, birthdayName);
    cv.put(BIRTHDAY_LAST_NAME, birthdayLastName);
    db.update(BIRTHDAY_TABLE_NAME, cv, BIRTHDAY_ID + " = ? ", new String[] {Integer.toString(id)} );
    return true;
}

public boolean deleteItem(long birthdayId) {
    SQLiteDatabase db = this.getWritableDatabase();
    return db.delete(BIRTHDAY_TABLE_NAME, BIRTHDAY_ID + "=" + birthdayId, null) > 0;
}

public Integer deleteBirthday(Integer id) {
    SQLiteDatabase db = this.getWritableDatabase();
    return db.delete(BIRTHDAY_TABLE_NAME,
            BIRTHDAY_ID + " = ? ",
            new String[] { Integer.toString(id) });
}
}

Answer 1

您的数据库实现可能存在错误。我不明白您如何使用 getBirthdayId 方法将 GridView 位置映射到数据库 ID。您可能希望将 DBHelper 的代码添加到您的帖子中。

一个快速的解决方案可能是向您的 Birthday 类添加一个 ID 属性，并在第一个 Activity 的 getData() 函数中设置该属性。然后，在 onItemClick 回调中，您可以从适配器的列表中获取您的 ID，而不是访问数据库，这可能对您的 UI 线程的性能不利。

这是您可以在 onItemClick 中执行的操作:

Birthday clickedBday = birthdays.get(position);
int birthdayId = clickedBday.getBIRTHDAY_ID()
Intent intent = new Intent(MainActivity.this, EditBirthdayActivity.class);
intent.putExtra(KEY_EXTRA_BIRTHDAY_ID, birthdayId);
startActivity(intent);