基于android studio的记事簿设计代码

以下是基于Android Studio的记事簿设计的代码示例，包括布局文件和Java代码：

1. 布局文件activity_main.xml：

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

    <EditText
        android:id="@+id/noteEditText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入笔记内容"/>

    <Button
        android:id="@+id/saveButton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="保存"/>

    <ListView
        android:id="@+id/noteListView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</LinearLayout>

2. Java代码MainActivity.java：

public class MainActivity extends AppCompatActivity {

    private EditText noteEditText;
    private Button saveButton;
    private ListView noteListView;
    private List<String> noteList;
    private ArrayAdapter<String> noteAdapter;

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

        noteEditText = findViewById(R.id.noteEditText);
        saveButton = findViewById(R.id.saveButton);
        noteListView = findViewById(R.id.noteListView);

        noteList = new ArrayList<>();
        noteAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, noteList);
        noteListView.setAdapter(noteAdapter);

        // 保存按钮点击事件
        saveButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 获取用户输入的笔记内容
                String note = noteEditText.getText().toString();

                // 将笔记内容保存到本地存储中
                SharedPreferences sharedPreferences = getSharedPreferences("note", MODE_PRIVATE);
                SharedPreferences.Editor editor = sharedPreferences.edit();
                editor.putString("note_" + System.currentTimeMillis(), note);
                editor.apply();

                // 将笔记内容添加到笔记列表中
                noteList.add(note);
                noteAdapter.notifyDataSetChanged();

                // 清空输入框
                noteEditText.setText("");
            }
        });

        // 笔记列表长按事件
        noteListView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
                // 获取用户长按的笔记内容
                String note = noteList.get(position);

                // 弹出对话框询问用户是否要删除该笔记
                AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
                builder.setTitle("提示");
                builder.setMessage("确定要删除该笔记吗？");
                builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // 从本地存储中删除该笔记
                        SharedPreferences sharedPreferences = getSharedPreferences("note", MODE_PRIVATE);
                        SharedPreferences.Editor editor = sharedPreferences.edit();
                        for (Map.Entry<String, ?> entry : sharedPreferences.getAll().entrySet()) {
                            if (entry.getValue().equals(note)) {
                                editor.remove(entry.getKey());
                                editor.apply();
                                break;
                            }
                        }

                        // 从笔记列表中删除该笔记
                        noteList.remove(position);
                        noteAdapter.notifyDataSetChanged();
                    }
                });
                builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });
                builder.show();

                return true;
            }
        });

        // 加载本地存储中已保存的笔记列表
        SharedPreferences sharedPreferences = getSharedPreferences("note", MODE_PRIVATE);
        for (Map.Entry<String, ?> entry : sharedPreferences.getAll().entrySet()) {
            noteList.add(entry.getValue().toString());
        }
        noteAdapter.notifyDataSetChanged();
    }
}

以上代码示例中，实现了笔记的保存、编辑和删除功能，并通过SharedPreferences来实现笔记的本地存储。