Android studio通讯录制作代码

好的，下面是一个简单的 Android Studio 通讯录制作代码示例，使用 SQLite 数据库来存储联系人信息：

1. 创建一个名为 "Contact" 的 Java 类，用于存储联系人信息。

public class Contact {
    private int id;
    private String name;
    private String phoneNumber;

    public Contact() {}

    public Contact(int id, String name, String phoneNumber) {
        this.id = id;
        this.name = name;
        this.phoneNumber = phoneNumber;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPhoneNumber() {
        return phoneNumber;
    }

    public void setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }
}

2. 创建一个名为 "DatabaseHelper" 的 Java 类，用于管理 SQLite 数据库。

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

    private static final String TABLE_CONTACTS = "contacts";
    private static final String COLUMN_ID = "id";
    private static final String COLUMN_NAME = "name";
    private static final String COLUMN_PHONE = "phone_number";

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

    @Override
    public void onCreate(SQLiteDatabase db) {
        String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS +
                "(" + COLUMN_ID + " INTEGER PRIMARY KEY," +
                COLUMN_NAME + " TEXT," +
                COLUMN_PHONE + " TEXT" + ")";
        db.execSQL(CREATE_CONTACTS_TABLE);
    }

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

    public void addContact(Contact contact) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(COLUMN_NAME, contact.getName());
        values.put(COLUMN_PHONE, contact.getPhoneNumber());
        db.insert(TABLE_CONTACTS, null, values);
        db.close();
    }

    public List<Contact> getAllContacts() {
        List<Contact> contactList = new ArrayList<>();
        String selectQuery = "SELECT * FROM " + TABLE_CONTACTS;
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);
        if (cursor.moveToFirst()) {
            do {
                Contact contact = new Contact();
                contact.setId(Integer.parseInt(cursor.getString(0)));
                contact.setName(cursor.getString(1));
                contact.setPhoneNumber(cursor.getString(2));
                contactList.add(contact);
            } while (cursor.moveToNext());
        }
        cursor.close();
        db.close();
        return contactList;
    }

    public void updateContact(Contact contact) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(COLUMN_NAME, contact.getName());
        values.put(COLUMN_PHONE, contact.getPhoneNumber());
        db.update(TABLE_CONTACTS, values, COLUMN_ID + " = ?",
                new String[] { String.valueOf(contact.getId()) });
        db.close();
    }

    public void deleteContact(Contact contact) {
        SQLiteDatabase db = this.getWritableDatabase();
        db.delete(TABLE_CONTACTS, COLUMN_ID + " = ?",
                new String[] { String.valueOf(contact.getId()) });
        db.close();
    }
}

3. 在布局文件中添加一个 RecyclerView 和一个 FloatingActionButton。

<android.support.v7.widget.RecyclerView
    android:id="@+id/recycler_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    android:layout_margin="16dp"
    android:src="@android:drawable/ic_input_add"/>

4. 在 MainActivity 类中实现 RecyclerView 和 FloatingActionButton 的逻辑。

public class MainActivity extends AppCompatActivity {
    private List<Contact> contactList = new ArrayList<>();
    private RecyclerView recyclerView;
    private ContactAdapter adapter;
    private DatabaseHelper db;

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

        recyclerView = findViewById(R.id.recycler_view);
        adapter = new ContactAdapter(contactList);
        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setAdapter(adapter);

        db = new DatabaseHelper(this);
        contactList.addAll(db.getAllContacts());
        adapter.notifyDataSetChanged();

        FloatingActionButton fab = findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this, AddContactActivity.class);
                startActivityForResult(intent, 1);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == 1) {
            if (resultCode == RESULT_OK) {
                Contact contact = (Contact) data.getSerializableExtra("contact");
                db.addContact(contact);
                contactList.clear();
                contactList.addAll(db.getAllContacts());
                adapter.notifyDataSetChanged();
            }
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

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

5. 在 AddContactActivity 类中实现添加联系人的逻辑。

public class AddContactActivity extends AppCompatActivity {
    private EditText inputName;
    private EditText inputPhoneNumber;

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

        inputName = findViewById(R.id.input_name);
        inputPhoneNumber = findViewById(R.id.input_phone_number);

        Button btnSave = findViewById(R.id.btn_save);
        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String name = inputName.getText().toString();
                String phoneNumber = inputPhoneNumber.getText().toString();
                if (!name.isEmpty() && !phoneNumber.isEmpty()) {
                    Contact contact = new Contact();
                    contact.setName(name);
                    contact.setPhoneNumber(phoneNumber);
                    Intent intent = new Intent();
                    intent.putExtra("contact", contact);
                    setResult(RESULT_OK, intent);
                    finish();
                }
            }
        });
    }
}

这样一个简单的 Android Studio 通讯录制作代码就完成了。当用户点击 FloatingActionButton 时，将跳转到 AddContactActivity 界面，用户可以输入联系人的姓名和电话号码，并保存到 SQLite 数据库中。在 MainActivity 中使用 RecyclerView 显示所有保存的联系人信息。