使用androidstudio实现签到功能。布局有一个按钮， 点击按钮数据库记录时间并显示在页面上。用Sqlite建立数据库，字段：用户、签到时间，每次调用这个页面的时候判断数据库里有没有今天该用户的签到记录，首页点击签到按钮，进入签到界面，判断逻辑先查询数据中是否有今日签到数据，如果有直接显示签到成功界面。否则显示签到按钮，点击签到按钮，将数据存入数据库，显示签到成功。

好的，首先需要创建一个布局文件，包含一个按钮和一个文本框用于显示签到时间。例如：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/sign_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="签到"
        android:layout_centerInParent="true"/>

    <TextView
        android:id="@+id/sign_time_textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="上次签到时间："
        android:layout_below="@id/sign_button"
        android:layout_centerHorizontal="true"/>

</RelativeLayout>

接着，在Java代码中，需要定义一个SQLiteOpenHelper类来创建和管理数据库。例如：

public class SignRecordDatabaseHelper extends SQLiteOpenHelper {

    private static final String DB_NAME = "sign_record.db";
    private static final int DB_VERSION = 1;

    public static final String TABLE_NAME = "sign_record";
    public static final String COL_USER = "user";
    public static final String COL_TIME = "time";

    public SignRecordDatabaseHelper(Context context) {
        super(context, DB_NAME, null, DB_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table " + TABLE_NAME + " ("
                + "_id integer primary key autoincrement, "
                + COL_USER + " text, "
                + COL_TIME + " text)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // no upgrade needed for now
    }

}

然后，在Activity中，需要实现按钮的点击事件，查询数据库中是否有今天该用户的签到记录，并根据查询结果显示不同的界面。例如：

public class MainActivity extends AppCompatActivity {

    private Button mSignButton;
    private TextView mSignTimeTextView;

    private SignRecordDatabaseHelper mDbHelper;

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

        mSignButton = findViewById(R.id.sign_button);
        mSignTimeTextView = findViewById(R.id.sign_time_textview);

        mDbHelper = new SignRecordDatabaseHelper(this);

        mSignButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String user = "John"; // replace with actual user name
                String today = new SimpleDateFormat("yyyy-MM-dd", Locale.getDefault()).format(new Date());
                SQLiteDatabase db = mDbHelper.getReadableDatabase();
                Cursor cursor = db.query(SignRecordDatabaseHelper.TABLE_NAME,
                        new String[]{SignRecordDatabaseHelper.COL_TIME},
                        SignRecordDatabaseHelper.COL_USER + "=? and " + SignRecordDatabaseHelper.COL_TIME + "=?",
                        new String[]{user, today},
                        null, null, null);
                if (cursor.moveToFirst()) {
                    // already signed in today
                    String time = cursor.getString(cursor.getColumnIndex(SignRecordDatabaseHelper.COL_TIME));
                    mSignButton.setVisibility(View.GONE);
                    mSignTimeTextView.setText("上次签到时间：" + time);
                    mSignTimeTextView.setVisibility(View.VISIBLE);
                } else {
                    // not signed in yet today
                    ContentValues values = new ContentValues();
                    values.put(SignRecordDatabaseHelper.COL_USER, user);
                    values.put(SignRecordDatabaseHelper.COL_TIME, today);
                    db.insert(SignRecordDatabaseHelper.TABLE_NAME, null, values);
                    mSignButton.setVisibility(View.GONE);
                    mSignTimeTextView.setText("签到成功，时间：" + today);
                    mSignTimeTextView.setVisibility(View.VISIBLE);
                }
                cursor.close();
                db.close();
            }
        });
    }

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

这样就实现了签到功能，每次点击按钮会根据数据库中是否有今天该用户的签到记录来显示不同的界面。