帮我用java写一个安卓带有boolean参数的方法

好的，以下是一个带有boolean参数的Java方法的示例：

public void doSomething(boolean isTrue) {
    if (isTrue) {
        // 如果isTrue为真，则执行某些操作
        System.out.println("isTrue is true");
    } else {
        // 如果isTrue为假，则执行其他操作
        System.out.println("isTrue is false");
    }
}

这个方法名为`doSomething`，它接受一个`boolean`类型的参数`isTrue`。如果`isTrue`为`true`，则输出`isTrue is true`；如果`isTrue`为`false`，则输出`isTrue is false`。在方法内部，您可以根据`isTrue`的值来执行适当的操作。

相关问题

用Java写一个带有登录功能的app

好的，我可以提供一些指导。

首先，你需要了解 Android 应用开发的基础知识，比如 Activity、Intent、布局等等。

接下来，我们来讲一下登录功能的实现。

1. 创建登录界面的布局文件

在 res/layout 目录下创建一个名为 activity_login.xml 的布局文件，用于显示登录界面。可以使用 EditText、Button 等控件来实现。

2. 创建登录逻辑

在 Java 中创建一个名为 LoginActivity 的类，继承自 AppCompatActivity。在该类中实现登录逻辑，比如将用户名和密码发送到服务器进行验证，并根据验证结果跳转到不同的页面。

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: 发送用户名和密码到服务器进行验证
                // 如果验证通过，跳转到主页面
                Intent intent = new Intent(LoginActivity.this, MainActivity.class);
                startActivity(intent);
                // 如果验证不通过，给出提示信息
                Toast.makeText(LoginActivity.this, "用户名或密码错误", Toast.LENGTH_SHORT).show();
            }
        });
    }
}

3. 在 AndroidManifest.xml 中注册 LoginActivity

在 AndroidManifest.xml 中添加以下代码，将 LoginActivity 注册到应用中：

<activity android:name=".LoginActivity" />

4. 调用 LoginActivity

在启动应用时，首先跳转到 LoginActivity，如果验证通过就跳转到主页面。

public class SplashActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // 检查是否登录，如果已登录就跳转到主页面，否则跳转到登录页面
        if (checkLogin()) {
            Intent intent = new Intent(this, MainActivity.class);
            startActivity(intent);
            finish();
        } else {
            Intent intent = new Intent(this, LoginActivity.class);
            startActivity(intent);
            finish();
        }
    }

    private boolean checkLogin() {
        // TODO: 检查是否已登录
        return false;
    }
}

以上是一个基本的登录功能的实现步骤。当然，实际开发中还需要考虑很多细节，比如数据加密、记住密码、注销登录等等。希望能对你有所帮助。

用初学者的角度，用安卓写一个课表，可以添加课表、查看课表、修改课表，数据库用Sqlite，编程语言用java，带有注释

首先，在 Android Studio 中创建一个新项目，然后创建一个名为 "Course" 的 SQLite 数据库，其中包含一个名为 "courses" 的表，该表包含 "id"、"name"、"day"、"time" 和 "location" 列。接着编写以下代码：

创建一个名为 "Course" 的 Java 类，该类表示课程对象，其中包含以下属性：

public class Course {
    private int id;
    private String name;
    private String day;
    private String time;
    private String location;

    public Course(int id, String name, String day, String time, String location) {
        this.id = id;
        this.name = name;
        this.day = day;
        this.time = time;
        this.location = location;
    }

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getDay() {
        return day;
    }

    public String getTime() {
        return time;
    }

    public String getLocation() {
        return location;
    }
}

创建一个名为 "DatabaseHelper" 的 Java 类，该类扩展了 SQLiteOpenHelper 类，用于创建和管理数据库：

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

    private static final String COURSE_TABLE_NAME = "courses";
    private static final String COURSE_COLUMN_ID = "id";
    private static final String COURSE_COLUMN_NAME = "name";
    private static final String COURSE_COLUMN_DAY = "day";
    private static final String COURSE_COLUMN_TIME = "time";
    private static final String COURSE_COLUMN_LOCATION = "location";

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

    @Override
    public void onCreate(SQLiteDatabase db) {
        String createCourseTable = "CREATE TABLE " + COURSE_TABLE_NAME + " (" +
                COURSE_COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                COURSE_COLUMN_NAME + " TEXT, " +
                COURSE_COLUMN_DAY + " TEXT, " +
                COURSE_COLUMN_TIME + " TEXT, " +
                COURSE_COLUMN_LOCATION + " TEXT)";
        db.execSQL(createCourseTable);
    }

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

    public boolean insertCourse(String name, String day, String time, String location) {
        SQLiteDatabase db = getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COURSE_COLUMN_NAME, name);
        contentValues.put(COURSE_COLUMN_DAY, day);
        contentValues.put(COURSE_COLUMN_TIME, time);
        contentValues.put(COURSE_COLUMN_LOCATION, location);
        long result = db.insert(COURSE_TABLE_NAME, null, contentValues);
        return result != -1;
    }

    public Cursor getAllCourses() {
        SQLiteDatabase db = getReadableDatabase();
        return db.rawQuery("SELECT * FROM " + COURSE_TABLE_NAME, null);
    }

    public boolean updateCourse(int id, String name, String day, String time, String location) {
        SQLiteDatabase db = getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COURSE_COLUMN_NAME, name);
        contentValues.put(COURSE_COLUMN_DAY, day);
        contentValues.put(COURSE_COLUMN_TIME, time);
        contentValues.put(COURSE_COLUMN_LOCATION, location);
        int result = db.update(COURSE_TABLE_NAME, contentValues, COURSE_COLUMN_ID + " = ?", new String[]{Integer.toString(id)});
        return result != 0;
    }

    public boolean deleteCourse(int id) {
        SQLiteDatabase db = getWritableDatabase();
        int result = db.delete(COURSE_TABLE_NAME, COURSE_COLUMN_ID + " = ?", new String[]{Integer.toString(id)});
        return result != 0;
    }
}

在主活动（MainActivity）中，实例化数据库助手和适配器，然后使用 ListView 显示所有课程。添加、编辑和删除课程的操作可以通过对话框完成。

public class MainActivity extends AppCompatActivity {
    private DatabaseHelper databaseHelper;
    private CursorAdapter cursorAdapter;

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

        databaseHelper = new DatabaseHelper(this);

        ListView listView = findViewById(R.id.list_view);
        cursorAdapter = new SimpleCursorAdapter(
                this,
                android.R.layout.simple_list_item_2,
                databaseHelper.getAllCourses(),
                new String[]{DatabaseHelper.COURSE_COLUMN_NAME, DatabaseHelper.COURSE_COLUMN_DAY},
                new int[]{android.R.id.text1, android.R.id.text2},
                0
        );
        listView.setAdapter(cursorAdapter);

        listView.setOnItemClickListener((parent, view, position, id) -> {
            Cursor cursor = (Cursor) parent.getItemAtPosition(position);
            int courseId = cursor.getInt(cursor.getColumnIndex(DatabaseHelper.COURSE_COLUMN_ID));
            String name = cursor.getString(cursor.getColumnIndex(DatabaseHelper.COURSE_COLUMN_NAME));
            String day = cursor.getString(cursor.getColumnIndex(DatabaseHelper.COURSE_COLUMN_DAY));
            String time = cursor.getString(cursor.getColumnIndex(DatabaseHelper.COURSE_COLUMN_TIME));
            String location = cursor.getString(cursor.getColumnIndex(DatabaseHelper.COURSE_COLUMN_LOCATION));
            showEditDialog(courseId, name, day, time, location);
        });

        FloatingActionButton fab = findViewById(R.id.fab);
        fab.setOnClickListener(view -> showAddDialog());
    }

    private void showAddDialog() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Add Course");

        View view = LayoutInflater.from(this).inflate(R.layout.dialog_edit_course, null);
        EditText nameEditText = view.findViewById(R.id.edit_text_name);
        Spinner daySpinner = view.findViewById(R.id.spinner_day);
        ArrayAdapter<String> dayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, getResources().getStringArray(R.array.days));
        dayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        daySpinner.setAdapter(dayAdapter);
        EditText timeEditText = view.findViewById(R.id.edit_text_time);
        EditText locationEditText = view.findViewById(R.id.edit_text_location);

        builder.setView(view);

        builder.setPositiveButton("Add", (dialog, which) -> {
            String name = nameEditText.getText().toString();
            String day = daySpinner.getSelectedItem().toString();
            String time = timeEditText.getText().toString();
            String location = locationEditText.getText().toString();

            boolean success = databaseHelper.insertCourse(name, day, time, location);
            if (success) {
                cursorAdapter.changeCursor(databaseHelper.getAllCourses());
            } else {
                Toast.makeText(this, "Failed to add course", Toast.LENGTH_SHORT).show();
            }
        });

        builder.setNegativeButton("Cancel", null);

        builder.show();
    }

    private void showEditDialog(int id, String name, String day, String time, String location) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Edit Course");

        View view = LayoutInflater.from(this).inflate(R.layout.dialog_edit_course, null);
        EditText nameEditText = view.findViewById(R.id.edit_text_name);
        nameEditText.setText(name);
        Spinner daySpinner = view.findViewById(R.id.spinner_day);
        ArrayAdapter<String> dayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, getResources().getStringArray(R.array.days));
        dayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        daySpinner.setAdapter(dayAdapter);
        daySpinner.setSelection(Arrays.asList(getResources().getStringArray(R.array.days)).indexOf(day));
        EditText timeEditText = view.findViewById(R.id.edit_text_time);
        timeEditText.setText(time);
        EditText locationEditText = view.findViewById(R.id.edit_text_location);
        locationEditText.setText(location);

        builder.setView(view);

        builder.setPositiveButton("Save", (dialog, which) -> {
            String newName = nameEditText.getText().toString();
            String newDay = daySpinner.getSelectedItem().toString();
            String newTime = timeEditText.getText().toString();
            String newLocation = locationEditText.getText().toString();

            boolean success = databaseHelper.updateCourse(id, newName, newDay, newTime, newLocation);
            if (success) {
                cursorAdapter.changeCursor(databaseHelper.getAllCourses());
            } else {
                Toast.makeText(this, "Failed to update course", Toast.LENGTH_SHORT).show();
            }
        });

        builder.setNegativeButton("Delete", (dialog, which) -> {
            boolean success = databaseHelper.deleteCourse(id);
            if (success) {
                cursorAdapter.changeCursor(databaseHelper.getAllCourses());
            } else {
                Toast.makeText(this, "Failed to delete course", Toast.LENGTH_SHORT).show();
            }
        });

        builder.setNeutralButton("Cancel", null);

        builder.show();
    }
}

在 res 文件夹中创建一个名为 "arrays.xml" 的文件，其中包含一组字符串数组，表示每周的某一天：

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="days">
        <item>Sunday</item>
        <item>Monday</item>
        <item>Tuesday</item>
        <item>Wednesday</item>
        <item>Thursday</item>
        <item>Friday</item>
        <item>Saturday</item>
    </string-array>
</resources>

在 res 文件夹中创建一个名为 "dialog_edit_course.xml" 的布局文件，其中包含用于添加和编辑课程的文本框和下拉列表。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="16dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Name" />

    <EditText
        android:id="@+id/edit_text_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Day" />

    <Spinner
        android:id="@+id/spinner_day"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Time" />

    <EditText
        android:id="@+id/edit_text_time"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Location" />

    <EditText
        android:id="@+id/edit_text_location"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

现在可以运行应用程序，添加、编辑和删除课程了！