在service中，无法修改activity代码怎么获得onActivityResult

如果你在服务(Service)中需要获得`onActivityResult`的回调，可以通过以下步骤实现：

1. 定义一个接口`OnActivityResultListener`，其中包含一个方法`onActivityResult(int requestCode, int resultCode, Intent data)`。

2. 在你的Activity中实现该接口，并在`onActivityResult`方法中调用该接口的`onActivityResult`方法。

3. 在你的Service中持有该接口的实例，并在需要获得`onActivityResult`回调的地方调用该接口的方法。

这样，当你的Activity收到`onActivityResult`回调时，就会通知到你的Service。

相关问题

无法修改activity中onActivityResult()方法，在service中怎么使用getMediaProjection

在Service中使用getMediaProjection方法，你需要先获取到MediaProjectionManager的实例，然后通过调用MediaProjectionManager的createScreenCaptureIntent方法来启动一个Activity，让用户授权应用程序访问屏幕内容。在用户授权后，Activity会返回一个MediaProjection对象，可以在Service中使用该对象进行屏幕录制或截屏。下面是一个示例代码：

public class MyService extends Service {
    private MediaProjectionManager mMediaProjectionManager;
    private MediaProjection mMediaProjection;

    @Override
    public void onCreate() {
        super.onCreate();
        mMediaProjectionManager = (MediaProjectionManager) getSystemService(MEDIA_PROJECTION_SERVICE);
    }

    private void startCapture() {
        Intent captureIntent = mMediaProjectionManager.createScreenCaptureIntent();
        startActivityForResult(captureIntent, REQUEST_CODE_SCREEN_CAPTURE);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == REQUEST_CODE_SCREEN_CAPTURE) {
            if (resultCode == RESULT_OK) {
                mMediaProjection = mMediaProjectionManager.getMediaProjection(resultCode, data);
                // 在这里可以使用mMediaProjection对象进行屏幕录制或截屏
            } else {
                // 用户取消了授权
            }
        }
    }
}

需要注意的是，在Service中使用getMediaProjection方法会启动一个Activity，因此需要在Activity的onActivityResult方法中获取MediaProjection对象，并在Service中使用该对象进行屏幕录制或截屏。

我要设计一个安卓记事本app,要求有登录界面，登录成功后跳转主界面，主界面上方包含搜索框，和类别下拉框，然后有两个按钮，一个按钮为计事，一个按钮为代办，点击两个按钮会进行切换，下方有加号，点击进入编辑界面进行添加，修改，并且能够选择是记事或者代办，代办要求有定时功能，并且添加会修改后主界面能够显示，长按主界面的记录可以删除，你能帮我用代码实现吗，数据库用SQLlite

好的，我可以帮你实现这个安卓记事本app。首先，我们需要创建一个新项目，然后在布局文件中创建登录界面和主界面的布局。在MainActivity中，我们可以设置登录界面和主界面的跳转逻辑，以及按钮的监听器。

在创建SQLite数据库之前，我们需要定义数据模型。为了实现记事和代办的区分，我们可以创建两个表来存储它们的数据。分别是Note和Task。它们的字段如下：

Note表：

- id（主键，自增）
- title（标题）
- content（内容）
- created_time（创建时间）

Task表：

- id（主键，自增）
- title（标题）
- content（内容）
- created_time（创建时间）
- deadline（截止时间）

接下来，我们可以创建一个DatabaseHelper类来管理数据库。在该类中，我们需要实现onCreate和onUpgrade方法，分别用于创建和升级数据库。

在MainActivity中，我们可以通过调用DatabaseHelper实例来进行数据库的操作。例如，当用户点击添加按钮时，我们可以通过调用insertNote或insertTask方法来将数据插入到Note或Task表中。当用户在主界面长按某条记录时，我们可以通过调用deleteNote或deleteTask方法来删除对应的数据。

最后，我们需要实现定时提醒的功能。我们可以使用AlarmManager来实现定时提醒。当用户设置了一个代办任务的截止时间时，我们可以通过调用setExact方法来设置一个定时提醒，该提醒将在截止时间到达时触发。

这就是实现该安卓记事本app的基本思路。以下是一些关键代码片段供你参考：

LoginActivity.java

public class LoginActivity extends AppCompatActivity {
    private EditText mUsernameEditText;
    private EditText mPasswordEditText;
    private Button mLoginButton;

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

        mUsernameEditText = findViewById(R.id.username_edit_text);
        mPasswordEditText = findViewById(R.id.password_edit_text);
        mLoginButton = findViewById(R.id.login_button);

        mLoginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String username = mUsernameEditText.getText().toString();
                String password = mPasswordEditText.getText().toString();

                // TODO: 校验用户名和密码是否正确
                // 如果正确，则跳转到MainActivity
                Intent intent = new Intent(LoginActivity.this, MainActivity.class);
                startActivity(intent);
                finish();
            }
        });
    }
}

MainActivity.java

public class MainActivity extends AppCompatActivity {
    private Spinner mCategorySpinner;
    private EditText mSearchEditText;
    private Button mNoteButton;
    private Button mTaskButton;
    private RecyclerView mRecyclerView;
    private FloatingActionButton mAddFab;

    private DatabaseHelper mDbHelper;

    private List<Note> mNoteList;
    private List<Task> mTaskList;
    private boolean mIsNoteMode = true;

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

        mCategorySpinner = findViewById(R.id.category_spinner);
        mSearchEditText = findViewById(R.id.search_edit_text);
        mNoteButton = findViewById(R.id.note_button);
        mTaskButton = findViewById(R.id.task_button);
        mRecyclerView = findViewById(R.id.recycler_view);
        mAddFab = findViewById(R.id.add_fab);

        mDbHelper = new DatabaseHelper(this);

        // 初始化RecyclerView
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
        mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL));

        // 初始化Spinner
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.category_array, android.R.layout.simple_spinner_item);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        mCategorySpinner.setAdapter(adapter);

        // 设置按钮监听器
        mNoteButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mIsNoteMode = true;
                updateRecyclerView();
            }
        });

        mTaskButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mIsNoteMode = false;
                updateRecyclerView();
            }
        });

        mAddFab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, EditActivity.class);
                intent.putExtra(EditActivity.EXTRA_IS_NOTE_MODE, mIsNoteMode);
                startActivityForResult(intent, EditActivity.REQUEST_CODE_ADD);
            }
        });

        // 更新RecyclerView
        updateRecyclerView();
    }

    @Override
    protected void onDestroy() {
        mDbHelper.close();
        super.onDestroy();
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        if (resultCode == RESULT_OK) {
            updateRecyclerView();
        }
        super.onActivityResult(requestCode, resultCode, data);
    }

    private void updateRecyclerView() {
        if (mIsNoteMode) {
            mNoteList = mDbHelper.queryAllNotes();
            NoteAdapter adapter = new NoteAdapter(mNoteList);
            mRecyclerView.setAdapter(adapter);
        } else {
            mTaskList = mDbHelper.queryAllTasks();
            TaskAdapter adapter = new TaskAdapter(mTaskList);
            mRecyclerView.setAdapter(adapter);
        }
    }

    private class NoteAdapter extends RecyclerView.Adapter<NoteViewHolder> {
        private List<Note> mNoteList;

        public NoteAdapter(List<Note> noteList) {
            mNoteList = noteList;
        }

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

        @Override
        public void onBindViewHolder(@NonNull NoteViewHolder holder, int position) {
            final Note note = mNoteList.get(position);
            holder.mTitleTextView.setText(note.getTitle());
            holder.mContentTextView.setText(note.getContent());
            holder.mCreatedTimeTextView.setText(note.getCreatedTime());

            holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    mDbHelper.deleteNoteById(note.getId());
                    updateRecyclerView();
                    return true;
                }
            });
        }

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

    private class NoteViewHolder extends RecyclerView.ViewHolder {
        private TextView mTitleTextView;
        private TextView mContentTextView;
        private TextView mCreatedTimeTextView;

        public NoteViewHolder(@NonNull View itemView) {
            super(itemView);
            mTitleTextView = itemView.findViewById(R.id.title_text_view);
            mContentTextView = itemView.findViewById(R.id.content_text_view);
            mCreatedTimeTextView = itemView.findViewById(R.id.created_time_text_view);
        }
    }

    private class TaskAdapter extends RecyclerView.Adapter<TaskViewHolder> {
        private List<Task> mTaskList;

        public TaskAdapter(List<Task> taskList) {
            mTaskList = taskList;
        }

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

        @Override
        public void onBindViewHolder(@NonNull TaskViewHolder holder, int position) {
            final Task task = mTaskList.get(position);
            holder.mTitleTextView.setText(task.getTitle());
            holder.mContentTextView.setText(task.getContent());
            holder.mCreatedTimeTextView.setText(task.getCreatedTime());
            holder.mDeadlineTextView.setText(task.getDeadline());

            holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    mDbHelper.deleteTaskById(task.getId());
                    updateRecyclerView();
                    return true;
                }
            });
        }

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

    private class TaskViewHolder extends RecyclerView.ViewHolder {
        private TextView mTitleTextView;
        private TextView mContentTextView;
        private TextView mCreatedTimeTextView;
        private TextView mDeadlineTextView;

        public TaskViewHolder(@NonNull View itemView) {
            super(itemView);
            mTitleTextView = itemView.findViewById(R.id.title_text_view);
            mContentTextView = itemView.findViewById(R.id.content_text_view);
            mCreatedTimeTextView = itemView.findViewById(R.id.created_time_text_view);
            mDeadlineTextView = itemView.findViewById(R.id.deadline_text_view);
        }
    }
}

DatabaseHelper.java

public class DatabaseHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "notes.db";
    private static final int DATABASE_VERSION = 1;

    private static final String CREATE_NOTE_TABLE_SQL = "CREATE TABLE " + Note.TABLE_NAME + " (" +
            Note.COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
            Note.COLUMN_TITLE + " TEXT," +
            Note.COLUMN_CONTENT + " TEXT," +
            Note.COLUMN_CREATED_TIME + " TEXT" +
            ");";

    private static final String CREATE_TASK_TABLE_SQL = "CREATE TABLE " + Task.TABLE_NAME + " (" +
            Task.COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
            Task.COLUMN_TITLE + " TEXT," +
            Task.COLUMN_CONTENT + " TEXT," +
            Task.COLUMN_CREATED_TIME + " TEXT," +
            Task.COLUMN_DEADLINE + " TEXT" +
            ");";

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

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

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

    public void insertNote(Note note) {
        SQLiteDatabase db = getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(Note.COLUMN_TITLE, note.getTitle());
        values.put(Note.COLUMN_CONTENT, note.getContent());
        values.put(Note.COLUMN_CREATED_TIME, note.getCreatedTime());
        db.insert(Note.TABLE_NAME, null, values);
        db.close();
    }

    public void insertTask(Task task) {
        SQLiteDatabase db = getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(Task.COLUMN_TITLE, task.getTitle());
        values.put(Task.COLUMN_CONTENT, task.getContent());
        values.put(Task.COLUMN_CREATED_TIME, task.getCreatedTime());
        values.put(Task.COLUMN_DEADLINE, task.getDeadline());
        db.insert(Task.TABLE_NAME, null, values);
        db.close();
    }

    public List<Note> queryAllNotes() {
        List<Note> noteList = new ArrayList<>();
        SQLiteDatabase db = getReadableDatabase();
        Cursor cursor = db.query(Note.TABLE_NAME, null, null, null, null, null, null);
        while (cursor.moveToNext()) {
            int id = cursor.getInt(cursor.getColumnIndex(Note.COLUMN_ID));
            String title = cursor.getString(cursor.getColumnIndex(Note.COLUMN_TITLE));
            String content = cursor.getString(cursor.getColumnIndex(Note.COLUMN_CONTENT));
            String createdTime = cursor.getString(cursor.getColumnIndex(Note.COLUMN_CREATED_TIME));
            noteList.add(new Note(id, title, content, createdTime));
        }
        cursor.close();
        db.close();
        return noteList;
    }

    public List<Task> queryAllTasks() {
        List<Task> taskList = new ArrayList<>();
        SQLiteDatabase db = getReadableDatabase();
        Cursor cursor = db.query(Task.TABLE_NAME, null, null, null, null, null, null);
        while (cursor.moveToNext()) {
            int id = cursor.getInt(cursor.getColumnIndex(Task.COLUMN_ID));
            String title = cursor.getString(cursor.getColumnIndex(Task.COLUMN_TITLE));
            String content = cursor.getString(cursor.getColumnIndex(Task.COLUMN_CONTENT));
            String createdTime = cursor.getString(cursor.getColumnIndex(Task.COLUMN_CREATED_TIME));
            String deadline = cursor.getString(cursor.getColumnIndex(Task.COLUMN_DEADLINE));
            taskList.add(new Task(id, title, content, createdTime, deadline));
        }
        cursor.close();
        db.close();
        return taskList;
    }

    public void deleteNoteById(int id) {
        SQLiteDatabase db = getWritableDatabase();
        db.delete(Note.TABLE_NAME, Note.COLUMN_ID + "=?", new String[]{String.valueOf(id)});
        db.close();
    }

    public void deleteTaskById(int id) {
        SQLiteDatabase db = getWritableDatabase();
        db.delete(Task.TABLE_NAME, Task.COLUMN_ID + "=?", new String[]{String.valueOf(id)});
        db.close();
    }
}

Note.java

public class Note {
    public static final String TABLE_NAME = "note";
    public static final String COLUMN_ID = "id";
    public static final String COLUMN_TITLE = "title";
    public static final String COLUMN_CONTENT = "content";
    public static final String COLUMN_CREATED_TIME = "created_time";

    private int mId;
    private String mTitle;
    private String mContent;
    private String mCreatedTime;

    public Note(int id, String title, String content, String createdTime) {
        mId = id;
        mTitle = title;
        mContent = content;
        mCreatedTime = createdTime;
    }

    public int getId() {
        return mId;
    }

    public String getTitle() {
        return mTitle;
    }

    public void setTitle(String title) {
        mTitle = title;
    }

    public String getContent() {
        return mContent;
    }

    public void setContent(String content) {
        mContent = content;
    }

    public String getCreatedTime() {
        return mCreatedTime;
    }

    public void setCreatedTime(String createdTime) {
        mCreatedTime = createdTime;
    }
}

Task.java

public class Task {
    public static final String TABLE_NAME = "task";
    public static final String COLUMN_ID = "id";
    public static final String COLUMN_TITLE = "title";
    public static final String COLUMN_CONTENT = "content";
    public static final String COLUMN_CREATED_TIME = "created_time";
    public static final String COLUMN_DEADLINE = "deadline";

    private int mId;
    private String mTitle;
    private String mContent;
    private String mCreatedTime;
    private String mDeadline;

    public Task(int id, String title, String content, String createdTime, String deadline) {
        mId = id;
        mTitle = title;
        mContent = content;
        mCreatedTime = createdTime;
        mDeadline = deadline;
    }

    public int getId() {
        return mId;
    }

    public String getTitle() {
        return mTitle;
    }

    public void setTitle(String title) {
        mTitle = title;
    }

    public String getContent() {
        return mContent;
    }

    public void setContent(String content) {
        mContent = content;
    }

    public String getCreatedTime() {
        return mCreatedTime;
    }

    public void setCreatedTime(String createdTime) {
        mCreatedTime = createdTime;
    }

    public String getDeadline() {
        return mDeadline;
    }

    public void setDeadline(String deadline) {
        mDeadline = deadline;
    }
}

EditActivity.java

public class EditActivity extends AppCompatActivity {
    public static final String EXTRA_IS_NOTE_MODE = "extra_is_note_mode";
    public static final int REQUEST_CODE_ADD = 1;
    public static final int REQUEST_CODE_EDIT = 2;

    private EditText mTitleEditText;
    private EditText mContentEditText;
    private EditText mDeadlineEditText;
    private Button mSaveButton;

    private DatabaseHelper mDbHelper;
    private boolean mIsNoteMode = true;
    private int mId = -1;

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

        mTitleEditText = findViewById(R.id.title_edit_text);
        mContentEditText = findViewById(R.id.content_edit_text);
        mDeadlineEditText = findViewById(R.id.deadline_edit_text);
        mSaveButton = findViewById(R.id.save_button);

        mDbHelper = new DatabaseHelper(this);

        mIsNoteMode = getIntent().getBooleanExtra(EXTRA_IS_NOTE_MODE, true);

        if (mIsNoteMode) {
            setTitle(getString(R.string.add_note));
        } else {
            setTitle(getString(R.string.add_task));
            mDeadlineEditText.setVisibility(View.VISIBLE);
        }

        mSaveButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String title = mTitleEditText.getText().toString();
                String content = mContentEditText.getText().toString();
                String createdTime = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault()).format(new Date());

                if (TextUtils.isEmpty(title)) {
                    Toast.makeText(EditActivity.this, getString(R.string.title_cannot_be_empty), Toast.LENGTH_SHORT).show();
                    return;
                }

                if (mIsNoteMode) {
                    Note note = new Note(-1, title, content, createdTime);
                    mDbHelper.insertNote(note);
                } else {
                    String deadline = mDeadlineEditText.getText().toString();
                    if (TextUtils.isEmpty(deadline)) {
                        Toast.makeText(EditActivity.this, getString(R.string.deadline_cannot_be_empty), Toast.LENGTH_SHORT).show();
                        return;
                    }

                    Task task = new Task(-1, title, content, createdTime, deadline);
                    mDbHelper.insertTask(task);

                    // 设置定时提醒
                    try {
                        Date date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault()).parse(deadline);
                        long timestamp = date.getTime();
                        Intent intent = new Intent(EditActivity.this, NotificationReceiver.class);
                        intent.putExtra(NotificationReceiver.EXTRA_TITLE, title);
                        PendingIntent pendingIntent = PendingIntent.getBroadcast(EditActivity.this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
                        AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                            alarmManager.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, timestamp, pendingIntent);
                        } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {