Activity

Activity新增了一個ActivityResultContracts，簡化一些寫法讓程式碼比較簡潔好理解。

registerForActivityResult(ActivityResultContracts):activity註冊將要執行甚麼功能。

ActivityResultContracts.RequestMultiplePermissions():訪問多個權限。
ActivityResultContracts.StartActivityForResult():跳轉頁面並回傳資料。

導入Library

implementation 'androidx.activity:activity-ktx:1.2.0-beta01'
implementation 'androidx.fragment:fragment:1.3.0-beta01'

詢問權限

//設置要訪問的權限的操作
private val multiplePermissions =
        registerForActivityResult(ActivityResultContracts.RequestMultiplePermissions()) { it ->
            it.entries.forEach {
                when (it.key) {
                    Manifest.permission.CAMERA -> {
                        Log.d("GG", "CAMERA ${it.value}")
                    }
                    Manifest.permission.READ_EXTERNAL_STORAGE -> {
                        Log.d("GG", "READ_EXTERNAL_STORAGE ${it.value}")
                    }
                    Manifest.permission.READ_CONTACTS -> {
                        Log.d("GG", "READ_CONTACTS ${it.value}")
                    }
                }
            }
        }
        
//調用launch
override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)

     multiplePermissions.launch(
         arrayOf(
                Manifest.permission.CAMERA,
                Manifest.permission.READ_EXTERNAL_STORAGE,
                Manifest.permission.READ_CONTACTS
            )
     )
}   

跳轉頁面

private val toMaMainActivity2 =
        registerForActivityResult(ActivityResultContracts.StartActivityForResult()) {
            if (it.resultCode == Activity.RESULT_OK) {
                Log.d("GG", "我正確的回來了")
            } else {
                Log.d("GG", "我不正確的回來了")
            }
        }

override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)

     toMaMainActivity2.launch(
         Intent(this, MainActivity2::class.java)
     )
}