使用Activity、Intent、事件处理等开发记单词app的代码

以下是一个使用Activity、Intent、事件处理等开发记单词app的基本代码示例：

MainActivity.java：

public class MainActivity extends AppCompatActivity {
    private EditText wordInput;
    private Button addWordButton;

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

        wordInput = findViewById(R.id.word_input);
        addWordButton = findViewById(R.id.add_word_button);

        addWordButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String word = wordInput.getText().toString();
                if (!TextUtils.isEmpty(word)) {
                    addWordToList(word);
                    wordInput.setText("");
                }
            }
        });
    }

    private void addWordToList(String word) {
        WordDatabaseHelper dbHelper = new WordDatabaseHelper(this);
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(WordDatabaseHelper.COLUMN_NAME_WORD, word);
        db.insert(WordDatabaseHelper.TABLE_NAME, null, values);
        db.close();

        Toast.makeText(this, "Word added to list.", Toast.LENGTH_SHORT).show();
    }

    public void openWordList(View view) {
        Intent intent = new Intent(this, WordListActivity.class);
        startActivity(intent);
    }
}

WordListActivity.java：

public class WordListActivity extends AppCompatActivity {
    private RecyclerView recyclerView;
    private WordListAdapter adapter;

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

        recyclerView = findViewById(R.id.word_list_recycler_view);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        adapter = new WordListAdapter(this);
        recyclerView.setAdapter(adapter);
    }
}

WordListAdapter.java：

public class WordListAdapter extends RecyclerView.Adapter<WordListAdapter.ViewHolder> {
    private List<String> wordList;
    private Context context;

    public WordListAdapter(Context context) {
        this.context = context;
        wordList = getWordList();
    }

    private List<String> getWordList() {
        List<String> list = new ArrayList<>();
        WordDatabaseHelper dbHelper = new WordDatabaseHelper(context);
        SQLiteDatabase db = dbHelper.getReadableDatabase();
        String[] projection = {WordDatabaseHelper.COLUMN_NAME_WORD};
        Cursor cursor = db.query(WordDatabaseHelper.TABLE_NAME, projection, null, null, null, null, null);
        while (cursor.moveToNext()) {
            String word = cursor.getString(cursor.getColumnIndexOrThrow(WordDatabaseHelper.COLUMN_NAME_WORD));
            list.add(word);
        }
        cursor.close();
        db.close();
        return list;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.word_list_item, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        final String word = wordList.get(position);
        holder.wordTextView.setText(word);
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(context, WordDetailActivity.class);
                intent.putExtra(WordDetailActivity.EXTRA_WORD, word);
                context.startActivity(intent);
            }
        });
    }

    @Override
    public int getItemCount() {
        return wordList.size();
    }

    public static class ViewHolder extends RecyclerView.ViewHolder {
        public TextView wordTextView;

        public ViewHolder(View itemView) {
            super(itemView);
            wordTextView = itemView.findViewById(R.id.word_text_view);
        }
    }
}

WordDetailActivity.java：

public class WordDetailActivity extends AppCompatActivity {
    public static final String EXTRA_WORD = "com.example.myapp.WORD";
    private TextView wordTextView;
    private EditText definitionEditText;
    private Button saveButton;

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

        wordTextView = findViewById(R.id.word_text_view);
        definitionEditText = findViewById(R.id.definition_edit_text);
        saveButton = findViewById(R.id.save_button);

        String word = getIntent().getStringExtra(EXTRA_WORD);
        wordTextView.setText(word);

        saveButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String definition = definitionEditText.getText().toString();
                if (!TextUtils.isEmpty(definition)) {
                    saveDefinition(wordTextView.getText().toString(), definition);
                    Toast.makeText(WordDetailActivity.this, "Definition saved.", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }

    private void saveDefinition(String word, String definition) {
        WordDatabaseHelper dbHelper = new WordDatabaseHelper(this);
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(WordDatabaseHelper.COLUMN_NAME_DEFINITION, definition);
        String selection = WordDatabaseHelper.COLUMN_NAME_WORD + " LIKE ?";
        String[] selectionArgs = { word };
        db.update(WordDatabaseHelper.TABLE_NAME, values, selection, selectionArgs);
        db.close();
    }
}

WordDatabaseHelper.java：

public class WordDatabaseHelper extends SQLiteOpenHelper {
    public static final int DATABASE_VERSION = 1;
    public static final String DATABASE_NAME = "WordList.db";
    public static final String TABLE_NAME = "word";
    public static final String COLUMN_NAME_WORD = "word";
    public static final String COLUMN_NAME_DEFINITION = "definition";
    public static final String SQL_CREATE_ENTRIES =
            "CREATE TABLE " + TABLE_NAME + " (" +
                    COLUMN_NAME_WORD + " TEXT PRIMARY KEY," +
                    COLUMN_NAME_DEFINITION + " TEXT)";
    public static final String SQL_DELETE_ENTRIES =
            "DROP TABLE IF EXISTS " + TABLE_NAME;

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

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

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

注意：这只是一个简单的代码示例，你可以根据你的实际需求和技术水平进行修改和优化。