remove和delete和empty

`remove` 和 `delete` 是两个不同的操作。`remove` 通常用于从容器中删除某个特定值的元素，而 `delete` 通常用于释放动态分配的内存。例如，在 C++ 中，可以使用 `delete` 释放通过 `new` 动态分配的内存。

`empty` 是一个成员函数，用于检查容器是否为空。如果容器为空，返回 `true`，否则返回 `false`。例如，在 C++ 中，可以使用 `empty` 检查一个 `vector` 是否为空，如下所示：

std::vector<int> myVector;

if (myVector.empty()) {
    std::cout << "The vector is empty" << std::endl;
}

如果 `myVector` 是空的，将输出 "The vector is empty"。

相关问题

Directory not empty

"Directory not empty" is an error message that indicates that a directory cannot be deleted because it still contains files or subdirectories. In order to delete a directory that is not empty, you must first remove or move all the files and subdirectories within it. Alternatively, you can use a command such as "rm -rf directory_name" to forcefully delete the directory and all its contents without confirmation. However, be careful when using the "rm" command, as it can permanently delete files and folders without any way to recover them.

根据你的回答给出布局文件和相关类

好的，下面是一个简单的电话簿应用程序的布局文件和相关类。这里使用了 Android Studio 自带的模板和默认布局，你可以根据自己的需要进行修改和完善。

activity_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="16dp"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/title_textview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/title_text"
        android:textAlignment="center"
        android:textSize="24sp"
        android:textStyle="bold" />

    <ListView
        android:id="@+id/contact_listview"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:divider="@null"
        android:dividerHeight="0dp" />

    <Button
        android:id="@+id/add_button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="@string/add_button_text" />

</LinearLayout>

contact_item.xml：

<?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:layout_margin="8dp"
    android:background="@color/colorPrimaryLight"
    android:orientation="vertical"
    android:padding="8dp">

    <TextView
        android:id="@+id/name_textview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="18sp" />

    <TextView
        android:id="@+id/phone_textview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="14sp" />

    <TextView
        android:id="@+id/other_info_textview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="14sp" />

</LinearLayout>

Contact.java：

public class Contact {
    private String name;
    private String phone;
    private String otherInfo;

    public Contact(String name, String phone, String otherInfo) {
        this.name = name;
        this.phone = phone;
        this.otherInfo = otherInfo;
    }

    public String getName() {
        return name;
    }

    public String getPhone() {
        return phone;
    }

    public String getOtherInfo() {
        return otherInfo;
    }
}

ContactAdapter.java：

public class ContactAdapter extends ArrayAdapter<Contact> {
    private int resourceId;

    public ContactAdapter(Context context, int resourceId, List<Contact> contacts) {
        super(context, resourceId, contacts);
        this.resourceId = resourceId;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        Contact contact = getItem(position);
        View view;
        ViewHolder viewHolder;
        if (convertView == null) {
            view = LayoutInflater.from(getContext()).inflate(resourceId, parent, false);
            viewHolder = new ViewHolder();
            viewHolder.nameTextView = (TextView) view.findViewById(R.id.name_textview);
            viewHolder.phoneTextView = (TextView) view.findViewById(R.id.phone_textview);
            viewHolder.otherInfoTextView = (TextView) view.findViewById(R.id.other_info_textview);
            view.setTag(viewHolder);
        } else {
            view = convertView;
            viewHolder = (ViewHolder) view.getTag();
        }
        viewHolder.nameTextView.setText(contact.getName());
        viewHolder.phoneTextView.setText(contact.getPhone());
        viewHolder.otherInfoTextView.setText(contact.getOtherInfo());
        return view;
    }

    class ViewHolder {
        TextView nameTextView;
        TextView phoneTextView;
        TextView otherInfoTextView;
    }
}

MainActivity.java：

public class MainActivity extends AppCompatActivity {
    private List<Contact> contactList = new ArrayList<>();
    private ContactAdapter contactAdapter;

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

        initView();
    }

    private void initView() {
        setTitle(R.string.app_name);

        ListView contactListView = (ListView) findViewById(R.id.contact_listview);

        contactAdapter = new ContactAdapter(this, R.layout.contact_item, contactList);
        contactListView.setAdapter(contactAdapter);

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

        contactListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Contact contact = contactList.get(position);
                AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
                builder.setTitle(R.string.delete_contact_title)
                        .setMessage(getString(R.string.delete_contact_message, contact.getName()))
                        .setPositiveButton(R.string.delete_button_text, new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                contactList.remove(position);
                                contactAdapter.notifyDataSetChanged();
                            }
                        })
                        .setNegativeButton(R.string.cancel_button_text, null)
                        .show();
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == RESULT_OK && requestCode == 1) {
            String name = data.getStringExtra("name");
            String phone = data.getStringExtra("phone");
            String otherInfo = data.getStringExtra("other_info");
            Contact contact = new Contact(name, phone, otherInfo);
            contactList.add(contact);
            contactAdapter.notifyDataSetChanged();
        }
    }
}

AddContactActivity.java：

public class AddContactActivity extends AppCompatActivity {
    private EditText nameEditText;
    private EditText phoneEditText;
    private EditText otherInfoEditText;

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

        initView();
    }

    private void initView() {
        setTitle(R.string.add_contact_title);

        nameEditText = (EditText) findViewById(R.id.name_edittext);
        phoneEditText = (EditText) findViewById(R.id.phone_edittext);
        otherInfoEditText = (EditText) findViewById(R.id.other_info_edittext);

        Button saveButton = (Button) findViewById(R.id.save_button);
        saveButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = nameEditText.getText().toString().trim();
                String phone = phoneEditText.getText().toString().trim();
                String otherInfo = otherInfoEditText.getText().toString().trim();
                if (TextUtils.isEmpty(name) || TextUtils.isEmpty(phone)) {
                    Toast.makeText(AddContactActivity.this, R.string.empty_input_tip, Toast.LENGTH_SHORT).show();
                } else {
                    Intent intent = new Intent();
                    intent.putExtra("name", name);
                    intent.putExtra("phone", phone);
                    intent.putExtra("other_info", otherInfo);
                    setResult(RESULT_OK, intent);
                    finish();
                }
            }
        });
    }
}

这些代码可以实现一个基本的电话簿应用程序，你可以根据自己的需求进行修改和扩展。