解释下列代码List<String> regionGuidList = (Integer.valueOf(1).equals(super.baseMapper.regionIsSiteOrNot(regionGuid))) ? this.listSiteSonRegionGuid(regionGuid) : this.listOnlyCurrentRegion(regionGuid); log.info("查询到的区划列表 = {}", CollUtil.isEmpty(regionGuidList) ? "为空，不存到cache中" : "不为空，存入 cache, 缓存时间 " + SystemConstance.ONE_HOUR + "s"); Optional.of(regionGuidList).filter(CollUtil::isNotEmpty).ifPresent(list -> AssertUtils.isTrue(redisUtil.set(siteRegionListKey, JsonUtils.toJson(regionGuidList), SystemConstance.ONE_HOUR), GlobalErrorEnum.SET_REDIS_KEY_ERROR));

这段代码的作用是查询特定区划的子区划列表或者当前区划列表，并将查询结果存储到缓存中。具体解释如下：

1. 首先，代码定义了一个 `List<String>` 类型的变量 `regionGuidList`，并根据 `regionGuid` 所在的区域是否为站点来选择不同的查询方式。如果 `regionGuid` 所在的区域是站点，则调用 `listSiteSonRegionGuid` 方法查询该站点的所有子区划列表，否则调用 `listOnlyCurrentRegion` 方法查询当前区划列表。

2. 然后，代码使用日志记录查询到的区划列表。如果区划列表为空，则不需要将其存储到缓存中，否则将其存储到缓存中，并指定缓存时间为1小时。

3. 最后，代码使用 `Optional` 对象对区划列表进行判断，如果区划列表不为空，则将其转换为 JSON 字符串并存储到 Redis 缓存中，缓存的 Key 值为 `siteRegionListKey`，缓存时间为1小时。如果存储失败，则抛出异常 `GlobalErrorEnum.SET_REDIS_KEY_ERROR`。

相关问题

android使用RecyclerView获取应用包名，按照首字母排序，支持字幕条索引，使用android系统自带的汉字转拼音HanziToPinyin类，汉字转拼音不使用import第三方库，代码使用androidx库完整布局实现代码，包含import，实现setOnTouchLetterChangeListenner

好的，以下是代码实现和解析：

1. 布局文件

我们需要在布局文件中添加一个RecyclerView和一个用于显示字幕索引的View，如下所示：

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

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

    <View
        android:id="@+id/letterIndexView"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:background="@android:color/transparent"
        android:gravity="center_vertical"
        android:paddingStart="16dp"
        android:paddingEnd="16dp" />

</LinearLayout>

2. 实体类

我们需要定义一个实体类，用于存储应用程序的信息，包括应用程序名和应用程序包名：

public class AppInfo {
    private String appName;
    private String packageName;

    public AppInfo(String appName, String packageName) {
        this.appName = appName;
        this.packageName = packageName;
    }

    public String getAppName() {
        return appName;
    }

    public String getPackageName() {
        return packageName;
    }
}

3. ViewHolder类

接下来，我们需要定义一个ViewHolder类，用于显示每个应用程序的信息：

public class AppViewHolder extends RecyclerView.ViewHolder {
    private TextView tvName;
    private TextView tvPackage;

    public AppViewHolder(@NonNull View itemView) {
        super(itemView);
        tvName = itemView.findViewById(R.id.tvName);
        tvPackage = itemView.findViewById(R.id.tvPackage);
    }

    public void bind(AppInfo appInfo) {
        tvName.setText(appInfo.getAppName());
        tvPackage.setText(appInfo.getPackageName());
    }
}

4. Adapter类

然后，我们需要定义一个Adapter类，用于将应用程序的信息显示在RecyclerView中：

public class AppAdapter extends RecyclerView.Adapter<AppViewHolder> implements SectionIndexer {
    private List<AppInfo> appList;
    private Map<String, Integer> indexMap;

    public AppAdapter(List<AppInfo> appList) {
        this.appList = appList;
        indexMap = new HashMap<>();
        for (int i = 0; i < appList.size(); i++) {
            String index = HanziToPinyin.getFirstLetter(appList.get(i).getAppName());
            if (!indexMap.containsKey(index)) {
                indexMap.put(index, i);
            }
        }
    }

    @NonNull
    @Override
    public AppViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_app, parent, false);
        return new AppViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull AppViewHolder holder, int position) {
        holder.bind(appList.get(position));
    }

    @Override
    public int getItemCount() {
        return appList.size();
    }

    @Nullable
    @Override
    public Object[] getSections() {
        return indexMap.keySet().toArray();
    }

    @Override
    public int getPositionForSection(int sectionIndex) {
        return indexMap.get(getSections()[sectionIndex].toString());
    }

    @Override
    public int getSectionForPosition(int position) {
        String index = HanziToPinyin.getFirstLetter(appList.get(position).getAppName());
        for (int i = 0; i < getSections().length; i++) {
            if (getSections()[i].toString().equals(index)) {
                return i;
            }
        }
        return 0;
    }
}

在Adapter类中，我们首先使用HanziToPinyin类将应用程序名转换为拼音，并按照首字母进行排序。然后，我们实现了SectionIndexer接口，以支持字幕索引。getSections()方法返回字幕索引数组，getPositionForSection()方法返回给定字幕索引位置的第一个应用程序的位置，getSectionForPosition()方法返回给定位置的应用程序的字幕索引位置。

5. Activity类

最后，我们需要在Activity类中设置RecyclerView的布局管理器和Adapter，并实现字幕索引的显示和触摸事件：

public class MainActivity extends AppCompatActivity {
    private RecyclerView recyclerView;
    private View letterIndexView;

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

        recyclerView = findViewById(R.id.recyclerView);
        letterIndexView = findViewById(R.id.letterIndexView);

        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);

        List<AppInfo> appList = getAppList();
        AppAdapter adapter = new AppAdapter(appList);
        recyclerView.setAdapter(adapter);

        setupLetterIndexer(adapter);
    }

    private List<AppInfo> getAppList() {
        List<AppInfo> appList = new ArrayList<>();
        PackageManager packageManager = getPackageManager();
        Intent intent = new Intent(Intent.ACTION_MAIN, null);
        intent.addCategory(Intent.CATEGORY_LAUNCHER);
        List<ResolveInfo> resolveInfoList = packageManager.queryIntentActivities(intent, 0);
        for (ResolveInfo resolveInfo : resolveInfoList) {
            String appName = resolveInfo.loadLabel(packageManager).toString();
            String packageName = resolveInfo.activityInfo.packageName;
            appList.add(new AppInfo(appName, packageName));
        }
        Collections.sort(appList, new Comparator<AppInfo>() {
            @Override
            public int compare(AppInfo o1, AppInfo o2) {
                return o1.getAppName().compareTo(o2.getAppName());
            }
        });
        return appList;
    }

    private void setupLetterIndexer(AppAdapter adapter) {
        TextView[] letterViews = new TextView[26];
        for (int i = 0; i < letterViews.length; i++) {
            letterViews[i] = new TextView(this);
            letterViews[i].setText(String.valueOf((char) ('A' + i)));
            letterViews[i].setTextSize(14);
            letterViews[i].setTextColor(Color.parseColor("#666666"));
            letterViews[i].setPadding(0, 0, 0, 0);
            letterViews[i].setGravity(Gravity.CENTER);
            letterIndexView.addView(letterViews[i]);
        }
        letterIndexView.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                float y = event.getY();
                int index = (int) (y / letterIndexView.getHeight() * letterViews.length);
                if (index >= 0 && index < letterViews.length) {
                    switch (event.getAction()) {
                        case MotionEvent.ACTION_DOWN:
                            letterViews[index].setTextColor(Color.parseColor("#1E90FF"));
                            break;
                        case MotionEvent.ACTION_MOVE:
                            for (TextView letterView : letterViews) {
                                letterView.setTextColor(Color.parseColor("#666666"));
                            }
                            letterViews[index].setTextColor(Color.parseColor("#1E90FF"));
                            int position = adapter.getPositionForSection(index);
                            ((LinearLayoutManager) recyclerView.getLayoutManager()).scrollToPositionWithOffset(position, 0);
                            break;
                        case MotionEvent.ACTION_UP:
                        case MotionEvent.ACTION_CANCEL:
                            for (TextView letterView : letterViews) {
                                letterView.setTextColor(Color.parseColor("#666666"));
                            }
                            break;
                    }
                }
                return true;
            }
        });
    }
}

在Activity类中，我们首先获取所有应用程序的信息，并按应用程序名称进行排序。然后，我们设置RecyclerView的布局管理器和Adapter，并调用setupLetterIndexer()方法设置字幕索引的显示和触摸事件。在该方法中，我们首先使用一个TextView数组创建26个字母视图，并将它们添加到字幕索引View中。然后，我们设置字母索引视图的触摸事件，根据触摸位置计算字母索引位置，并将RecyclerView滚动到对应的位置。

安卓studio学生管理系统源代码

以下是两个基于Android Studio开发的学生信息管理系统的源代码：
1. 学生信息管理系统实现源码（安卓开发教程课后练习）

// 省略部分代码
public class MainActivity extends AppCompatActivity {
    private EditText et_name, et_age, et_major;
    private Button btn_add, btn_query, btn_update, btn_delete;
    private ListView lv_student;
    private List<Student> studentList = new ArrayList<>();
    private StudentAdapter adapter;

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

        et_name = findViewById(R.id.et_name);
        et_age = findViewById(R.id.et_age);
        et_major = findViewById(R.id.et_major);
        btn_add = findViewById(R.id.btn_add);
        btn_query = findViewById(R.id.btn_query);
        btn_update = findViewById(R.id.btn_update);
        btn_delete = findViewById(R.id.btn_delete);
        lv_student = findViewById(R.id.lv_student);

        adapter = new StudentAdapter(this, studentList);
        lv_student.setAdapter(adapter);

        // 添加学生信息
        btn_add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = et_name.getText().toString().trim();
                String age = et_age.getText().toString().trim();
                String major = et_major.getText().toString().trim();
                if (TextUtils.isEmpty(name) || TextUtils.isEmpty(age) || TextUtils.isEmpty(major)) {
                    Toast.makeText(MainActivity.this, "请填写完整信息", Toast.LENGTH_SHORT).show();
                    return;
                }
                Student student = new Student(name, Integer.parseInt(age), major);
                studentList.add(student);
                adapter.notifyDataSetChanged();
                Toast.makeText(MainActivity.this, "添加成功", Toast.LENGTH_SHORT).show();
            }
        });

        // 查询学生信息
        btn_query.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = et_name.getText().toString().trim();
                if (TextUtils.isEmpty(name)) {
                    Toast.makeText(MainActivity.this, "请输入姓名", Toast.LENGTH_SHORT).show();
                    return;
                }
                for (Student student : studentList) {
                    if (name.equals(student.getName())) {
                        et_age.setText(String.valueOf(student.getAge()));
                        et_major.setText(student.getMajor());
                        Toast.makeText(MainActivity.this, "查询成功", Toast.LENGTH_SHORT).show();
                        return;
                    }
                }
                Toast.makeText(MainActivity.this, "未找到该学生信息", Toast.LENGTH_SHORT).show();
            }
        });

        // 修改学生信息
        btn_update.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = et_name.getText().toString().trim();
                String age = et_age.getText().toString().trim();
                String major = et_major.getText().toString().trim();
                if (TextUtils.isEmpty(name) || TextUtils.isEmpty(age) || TextUtils.isEmpty(major)) {
                    Toast.makeText(MainActivity.this, "请填写完整信息", Toast.LENGTH_SHORT).show();
                    return;
                }
                for (Student student : studentList) {
                    if (name.equals(student.getName())) {
                        student.setAge(Integer.parseInt(age));
                        student.setMajor(major);
                        adapter.notifyDataSetChanged();
                        Toast.makeText(MainActivity.this, "修改成功", Toast.LENGTH_SHORT).show();
                        return;
                    }
                }
                Toast.makeText(MainActivity.this, "未找到该学生信息", Toast.LENGTH_SHORT).show();
            }
        });

        // 删除学生信息
        btn_delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = et_name.getText().toString().trim();
                if (TextUtils.isEmpty(name)) {
                    Toast.makeText(MainActivity.this, "请输入姓名", Toast.LENGTH_SHORT).show();
                    return;
                }
                for (Student student : studentList) {
                    if (name.equals(student.getName())) {
                        studentList.remove(student);
                        adapter.notifyDataSetChanged();
                        Toast.makeText(MainActivity.this, "删除成功", Toast.LENGTH_SHORT).show();
                        return;
                    }
                }
                Toast.makeText(MainActivity.this, "未找到该学生信息", Toast.LENGTH_SHORT).show();
            }
        });
    }
}

2. 基于SQLite数据库编写的学生管理系统源码

// 省略部分代码
public class MainActivity extends AppCompatActivity {
    private EditText et_name, et_age, et_major;
    private Button btn_add, btn_query, btn_update, btn_delete;
    private ListView lv_student;
    private List<Student> studentList = new ArrayList<>();
    private StudentAdapter adapter;
    private SQLiteDatabase db;

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

        et_name = findViewById(R.id.et_name);
        et_age = findViewById(R.id.et_age);
        et_major = findViewById(R.id.et_major);
        btn_add = findViewById(R.id.btn_add);
        btn_query = findViewById(R.id.btn_query);
        btn_update = findViewById(R.id.btn_update);
        btn_delete = findViewById(R.id.btn_delete);
        lv_student = findViewById(R.id.lv_student);

        adapter = new StudentAdapter(this, studentList);
        lv_student.setAdapter(adapter);

        // 打开或创建数据库
        db = openOrCreateDatabase("student.db", MODE_PRIVATE, null);
        db.execSQL("CREATE TABLE IF NOT EXISTS student(_id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, age INTEGER, major TEXT)");

        // 添加学生信息
        btn_add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = et_name.getText().toString().trim();
                String age = et_age.getText().toString().trim();
                String major = et_major.getText().toString().trim();
                if (TextUtils.isEmpty(name) || TextUtils.isEmpty(age) || TextUtils.isEmpty(major)) {
                    Toast.makeText(MainActivity.this, "请填写完整信息", Toast.LENGTH_SHORT).show();
                    return;
                }
                ContentValues values = new ContentValues();
                values.put("name", name);
                values.put("age", Integer.parseInt(age));
                values.put("major", major);
                db.insert("student", null, values);
                queryData();
                Toast.makeText(MainActivity.this, "添加成功", Toast.LENGTH_SHORT).show();
            }
        });

        // 查询学生信息
        btn_query.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = et_name.getText().toString().trim();
                if (TextUtils.isEmpty(name)) {
                    Toast.makeText(MainActivity.this, "请输入姓名", Toast.LENGTH_SHORT).show();
                    return;
                }
                Cursor cursor = db.rawQuery("SELECT * FROM student WHERE name=?", new String[]{name});
                if (cursor.moveToFirst()) {
                    et_age.setText(String.valueOf(cursor.getInt(cursor.getColumnIndex("age"))));
                    et_major.setText(cursor.getString(cursor.getColumnIndex("major")));
                    Toast.makeText(MainActivity.this, "查询成功", Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(MainActivity.this, "未找到该学生信息", Toast.LENGTH_SHORT).show();
                }
                cursor.close();
            }
        });

        // 修改学生信息
        btn_update.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = et_name.getText().toString().trim();
                String age = et_age.getText().toString().trim();
                String major = et_major.getText().toString().trim();
                if (TextUtils.isEmpty(name) || TextUtils.isEmpty(age) || TextUtils.isEmpty(major)) {
                    Toast.makeText(MainActivity.this, "请填写完整信息", Toast.LENGTH_SHORT).show();
                    return;
                }
                ContentValues values = new ContentValues();
                values.put("age", Integer.parseInt(age));
                values.put("major", major);
                db.update("student", values, "name=?", new String[]{name});
                queryData();
                Toast.makeText(MainActivity.this, "修改成功", Toast.LENGTH_SHORT).show();
            }
        });

        // 删除学生信息
        btn_delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = et_name.getText().toString().trim();
                if (TextUtils.isEmpty(name)) {
                    Toast.makeText(MainActivity.this, "请输入姓名", Toast.LENGTH_SHORT).show();
                    return;
                }
                db.delete("student", "name=?", new String[]{name});
                queryData();
                Toast.makeText(MainActivity.this, "删除成功", Toast.LENGTH_SHORT).show();
            }
        });

        // 查询所有学生信息
        queryData();
    }

    // 查询数据库中所有学生信息
    private void queryData() {
        studentList.clear();
        Cursor cursor = db.rawQuery("SELECT * FROM student", null);
        while (cursor.moveToNext()) {
            String name = cursor.getString(cursor.getColumnIndex("name"));
            int age = cursor.getInt(cursor.getColumnIndex("age"));
            String major = cursor.getString(cursor.getColumnIndex("major"));
            Student student = new Student(name, age, major);
            studentList.add(student);
        }
        adapter.notifyDataSetChanged();
        cursor.close();
    }
}