Android Studio の 自定義代碼塊摺疊

0x00 前言

最近在整理項目中的代碼，由於項目的代碼比較久遠，某些類的代碼量相對比較龐大，新人在接手維護這個類的時候熟悉起來比較困難，僅僅依靠文檔和註釋理解起來也比較喫力。後來想起IntelliJ IDEA中有Custom code folding regions的操作方式，可以將代碼塊歸納摺疊爲標籤的形式，讓代碼看起來規整了很多。

形成類似如下的效果：

在Structure導航中看起來也比較清晰

0x01 操作實現

class MainActivity : AppCompatActivity() {

    //<editor-fold desc="* 1. 這種成員變量">
    private lateinit var appBarConfiguration: AppBarConfiguration
    //</editor-fold>

    //<editor-fold desc="* 2. 主要的函數方法">
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val toolbar: Toolbar = findViewById(R.id.toolbar)
        setSupportActionBar(toolbar)

        val fab: FloatingActionButton = findViewById(R.id.fab)
        fab.setOnClickListener { view ->
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show()
        }
        val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
        val navView: NavigationView = findViewById(R.id.nav_view)
        val navController = findNavController(R.id.nav_host_fragment)
        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        appBarConfiguration = AppBarConfiguration(setOf(
                R.id.nav_home, R.id.nav_gallery, R.id.nav_slideshow), drawerLayout)
        setupActionBarWithNavController(navController, appBarConfiguration)
        navView.setupWithNavController(navController)
    }

    override fun onCreateOptionsMenu(menu: Menu): Boolean {
        // Inflate the menu; this adds items to the action bar if it is present.
        menuInflater.inflate(R.menu.main, menu)
        return true
    }
    //</editor-fold>

    //<editor-fold desc="* 3. 輔助的函數方法">
    override fun onSupportNavigateUp(): Boolean {
        val navController = findNavController(R.id.nav_host_fragment)
        return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
    }
    //</editor-fold>
}

選擇好需要摺疊的代碼片段，然後使用快捷鍵或者在菜單欄中選擇如下action

在彈出的菜單中選擇，<editor-fold..>或者region..endregion中的任意一個都可以。

對於以上兩者的區別，官方給出的解釋是

As you can see there are two custom folding items: “<editor-fold…>” for NetBeans-like style and “region…endregion” for VisualStudio style

添加好對應的摺疊註釋

就可以實現像摺疊展開studio的其他代碼塊一樣的效果，進行展開收納