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AndroidManifest.xml에 아래와 같이 권한을 추가 한다

    <uses-feature
        android:name="android.hardware.telephony"
        android:required="false" />

    <uses-feature android:name="android.permission.CALL_PHONE" />
    <uses-permission android:name="android.permission.CALL_PHONE" />

 MainActivity안에 아래와 같이 버튼에 이벤트를 연결한다.

    private fun init() {
        val callButton : Button = findViewById(R.id.callButton)
        callButton.setOnClickListener( View.OnClickListener { _ -> runCall() })
    }

    private fun runCall() {
        val intent = Intent(Intent.ACTION_CALL, Uri.parse("tel:01234561492"))
        val status = ActivityCompat.checkSelfPermission(this, 
            android.Manifest.permission.CALL_PHONE) == PackageManager.PERMISSION_GRANTED
        if (status) {
            startActivity(intent)
        } else {
            Log.i("TAG", "Unable to launch call");
            ActivityCompat.requestPermissions(this, 
                arrayOf<String>(android.Manifest.permission.CALL_PHONE), CALL_REQUEST)
        }
    }

아래와 같이 onRequestPermissionsReseult()를 오버라이딩 해주면, 권한 컨펌 즉시 콜이 걸리게 된다.

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        when (requestCode) {
            CALL_REQUEST -> {
                if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    Toast.makeText(this, "통화가 가능 합니다", Toast.LENGTH_LONG).show()
                    runCall()
                } else {
                    Toast.makeText(this, "통화가 거절 되었습니다", Toast.LENGTH_LONG).show()
                }
            }
        }
    }

■  HTTP 1.0 RFC
https://datatracker.ietf.org/doc/html/rfc1945

■  HTTP 1.1 RFC
https://datatracker.ietf.org/doc/html/rfc2616

■ 메시지 포멧
□ Request
Request-Line = Method SP Request-URI SP HTTP-Version CRLF

□ 예시1
GET /user/chobocho27 HTTP/1.1

□ 예시2
GET / HTTP/1.1
Host: 127.0.0.1:5000
Connection: keep-alive
Cache-Control: max-age=0
Sec-Ch-Ua: "Not/A)Brand";v="99", "Google Chrome";v="115", "Chromium";v="115"
Sec-Ch-Ua-Mobile: ?0
Sec-Ch-Ua-Platform: "Windows"
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Sec-Fetch-Site: none
Sec-Fetch-Mode: navigate
Sec-Fetch-User: ?1
Sec-Fetch-Dest: document
Accept-Encoding: gzip, deflate, br
Accept-Language: ko-KR,ko;q=0.9,en-US;q=0.8,en;q=0.7

□ Response
HTTP/1.1 200 OK