코딩도상국

안녕하세요. 

빠르게 Estimote의 Beacon 세 개를 이용해 안드로이드 폰으로 삼변측량을 구현하기 위해 AltBeacon Library를 사용했습니다. (Beacon 구현)

간단하기 때문에 쉽게 구현할 수 있습니다. 중요한 부분만 집어 이야기 하겠습니다.

altbeacon.github.io/android-beacon-library/index.html

1. Configure (build.gradle)

2. Permissions (AndroidManifest.xml)

안드로이드 버전 별 이슈는 위 사이트 참고

3. Implements (MainActivity.java)

altbeacon.github.io/android-beacon-library/samples.html

Ranging Example Code를 사용하여 Distance를 구할 수 있다. ( getDistance() 메소드 사용 )

하지만 getDistance 메소드 대신 아래 메소드를 추천합니다. ( 실제 실험 환경의 곡선을 가진 방정식 )

protected static double calculateDistance(int measuredPower, double rssi) {
  if (rssi == 0) {
    return -1.0; // if we cannot determine distance, return -1.
  }
  double ratio = rssi*1.0/measuredPower;
  if (ratio < 1.0) {
    return Math.pow(ratio,10);
  }
  else {
    double distance =  (0.89976)*Math.pow(ratio,7.7095) + 0.111;
    return distance;
  }
}

4. Error (AltBeacon 종속성 추가)

오류

Caused by: java.lang.ClassNotFoundException: Didn't find class "androidx.localbroadcastmanager.content.LocalBroadcastManager"

해결 (build.gradle에 추가)

 implementation 'androidx.localbroadcastmanager:localbroadcastmanager:1.0.0'

5. 응용 (Beacon Parser)

Beacon은 대표적으로 Estimote(Apple)와 EddyStone(Google)이 있으므로, Beacon Scan 하기 위한 Beacon을 parsing 해야 한다. 

위 오픈소스 설명이 굉장히 잘 돼있기 때문에 자세한 설명은 하지 않고, 큰 틀로 이야기를 진행했습니다.

iBeacon이 Eddystone보다 약 2년 정도 일찍 출시되어, Beacon 하면 iBeacon을 많이 이야기합니다. 

후속작인 Eddystone은 URL을 Broadcasting 하여 주변 기기에게 전송할 수 있고, TLM을 통해 비콘의 상태를 확인할 수 있습니다. 

www.youtube.com/watch?v=HRP1tfXHiVg&t=67s

passkit.com/blog/what-is-eddystone-and-is-it-the-future-of-beacon-tech/

cf) 삼변측량 Library

github.com/lemmingapex/trilateration

Explicit Intent는인텐트를 충족하는 애플리케이션이 무엇인지 지정합니다. 이를 위해 대상 앱의 패키지 이름 또는 완전히 자격을 갖춘 구성 요소 클래스 이름을 제공.

ex) Page1에서 Page2로 넘어갈 때, 사용되는 노드 같은 것

0. AndroidManifest.xml ( SecondActivty를 manifest에 추가 )

        <activity android:name=".SecondActivity">

        </activity>

1. first_layout.xml

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

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Button"
        android:onClick="ClickButton"
        android:id="@+id/btn">

    </Button>

</LinearLayout>

2. MainActivity.java (Activity A)

package com.example.project8_intent;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.first_layout);
		
        // Button Event
        Button btn = (Button)findViewById(R.id.btn);
        btn.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view)
            {
                // intent ( Start Point : Main -> End Point : SecondActivity )
                Intent intent = new Intent(getApplicationContext(), SecondActivity.class);
                startActivity(intent);
            }
        });
    }
}

 Button Click했을 때( Start Point : MainActivity ---> End Point : SecondActivity )

3. second_layout.xml

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

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Second Button"
        android:id="@+id/btn2"
        >

    </Button>

</LinearLayout>

4. SecondActivity.java

package com.example.project8_intent;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

public class SecondActivity extends AppCompatActivity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.second_layout);

        Button btn = (Button)findViewById(R.id.btn2);
		
        // SecondActivity 종료
        btn.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view){
                finish();

            }
        });
    }
}

 Button Click했을 때( SecondActivity 종료)

developer.android.com/guide/components/intents-filters?hl=ko#java

1. Create Option menu 

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">

</menu>

2. Create Menu Item 

test_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/test_1"
        android:title="Test1">
    </item>

    <item
        android:id="@+id/test_2"
        android:title="Test2">
    </item>

    <item
        android:id="@+id/test_3"
        android:title="Test3">
    </item>
</menu>

MainActivity.java

onCreate OptionsMenu method 생성  ( 직접 작성해도 됨 )

ackage com.example.project7_optionmenu;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.Menu;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
	
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        return super.onCreateOptionsMenu(menu);
    }
}

코드 추가 ( xml, java 연결 )

...
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
		
        // 코드 추가
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.test_menu, menu);
		//
        return super.onCreateOptionsMenu(menu);
    }
...

2. Event 

...
    // option menu event method
    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        switch(item.getItemId())
        {
            case R.id.test_1:
                Toast.makeText(getApplicationContext(), "Test1", Toast.LENGTH_LONG).show();
            case R.id.test_2:
                Toast.makeText(getApplicationContext(), "Test2", Toast.LENGTH_LONG).show();
            case R.id.test_3:
                Toast.makeText(getApplicationContext(), "Test3", Toast.LENGTH_LONG).show();
        }

        return super.onOptionsItemSelected(item);
    }
    ...

full main java code 

package com.example.project7_optionmenu;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

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

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.test_menu, menu);

        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        switch(item.getItemId())
        {
            case R.id.test_1:
                Toast.makeText(getApplicationContext(), "Test1", Toast.LENGTH_LONG).show();
            case R.id.test_2:
                Toast.makeText(getApplicationContext(), "Test2", Toast.LENGTH_LONG).show();
            case R.id.test_3:
                Toast.makeText(getApplicationContext(), "Test3", Toast.LENGTH_LONG).show();
        }

        return super.onOptionsItemSelected(item);
    }
}

developer.android.com/guide/topics/ui/menus?hl=ko

xml

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

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <EditText
            android:id="@+id/Edit1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:hint="숫자1">
        </EditText>

        <EditText
            android:id="@+id/Edit2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:hint="숫자2">
        </EditText>

        <Button
            android:id="@+id/BtnAdd"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:text="더하기"
            android:onClick="AddClick">

        </Button>

        <Button
            android:id="@+id/BtnSub"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:text="뺴기"
            android:onClick="SubClick">

        </Button>

        <Button
            android:id="@+id/BtnMulti"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:text="곱하기"
            android:onClick="MultiClick">

        </Button>

        <Button
            android:id="@+id/BtnDiv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:text="나누기"
            android:onClick="DivClick">

        </Button>

        <TextView
            android:id="@+id/TextResult"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="30dp"
            android:textColor="#FF0000"
            android:text="계산 결과 : "
            >
        </TextView>


    </LinearLayout>


</LinearLayout>

java

package com.example.homework2;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    EditText edit1, edit2;
    TextView textResult;
    String num1, num2, tmp;
    Integer result;


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


        edit1 = (EditText)findViewById(R.id.Edit1);
        edit2 = (EditText)findViewById(R.id.Edit2);

        textResult = (TextView)findViewById(R.id.TextResult);

    }

    // 덧셈 method
    public void AddClick(View target)
    {
        num1 = edit1.getText().toString();
        num2 = edit2.getText().toString();

        if ((isInteger(num1) & isInteger(num2))==1)
        {
            result = Integer.parseInt(num1) + Integer.parseInt(num2);
            tmp = "계산 결과 : " + result.toString();
            textResult.setText(tmp);
        }
        else
        {
            Toast.makeText(getApplicationContext(), "No Number", Toast.LENGTH_LONG).show();
        }

    }

    // 뺄셈 method
    public void SubClick(View target)
    {
        num1 = edit1.getText().toString();
        num2 = edit2.getText().toString();

        if ((isInteger(num1) & isInteger(num2))==1)
        {
            result = Integer.parseInt(num1) - Integer.parseInt(num2);
            tmp = "계산 결과 : " + result.toString();
            textResult.setText(tmp);
        }
        else
        {
            Toast.makeText(getApplicationContext(), "No Number", Toast.LENGTH_LONG).show();
        }
    }

    // 곱셈 method
    public void MultiClick(View target)
    {
        num1 = edit1.getText().toString();
        num2 = edit2.getText().toString();

        if ((isInteger(num1) & isInteger(num2))==1)
        {
            result = Integer.parseInt(num1) * Integer.parseInt(num2);
            tmp = "계산 결과 : " + result.toString();
            textResult.setText(tmp);
        }
        else
        {
            Toast.makeText(getApplicationContext(), "No Number", Toast.LENGTH_LONG).show();
        }
    }

    // 나눗셈 method
    public void DivClick(View target)
    {
        num1 = edit1.getText().toString();
        num2 = edit2.getText().toString();

        if ((isInteger(num1) & isInteger(num2))==1)
        {
            result = Integer.parseInt(num1) / Integer.parseInt(num2);
            tmp = "계산 결과 : " + result.toString();
            textResult.setText(tmp);
        }
        else
        {
            Toast.makeText(getApplicationContext(), "No Number", Toast.LENGTH_LONG).show();
        }
    }

    // integer type method
    static int isInteger(String s) {
        try {
            Integer.parseInt(s);
            return 1;
        } catch(NumberFormatException e) {
            return 0;
        }
    }

}

EditText

// EditText
EditText edit = (EditText)findViewById(R.id.Edit);

// return string 
edit.getText().toString();

TextView

// TextView
text = (TextView)findViewById(R.id.Text);

text.setText(edittext.getText());

developer.android.com/reference/android/widget/EditText

developer.android.com/reference/android/widget/TextView

LinearLayout 을 잘만 사용해도 어느 정도 디자인을 꾸밀 수 있다.

1. LinearLayout xml 생성

<LinearLayout xmlns : android = "http://schemas.android.com/apk/res/android"
   android : layout_width = "match_parent"
   android : layout_height = "match_parent"
   android : paddingLeft = "16dp"
   android : paddingRight = "16dp"
   android : orientation = "horizontal"
   android : gravity = "center">

   <!-여기에 다른 위젯 또는 레이아웃 태그를 포함합니다. 이것들은 고려됩니다
           선형 레이아웃의 "자식보기"또는 "자식"->

 </ LinearLayout>

XML attributes

2. LinearLayout 안에 LinearLayout 넣기

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

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:orientation="horizontal"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:layout_marginTop="20dp"
        >
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:background="#FF0000">
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:background="#0000FF">
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:background="#008000">
        </LinearLayout>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="300dp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:orientation="vertical">
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="3"
            android:background="#FFFF00"
            >
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="2"
            android:background="#0000FF"
            >
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="3"
            android:background="#008000"
            >
        </LinearLayout>

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:orientation="horizontal">

        <Button
            android:id="@+id/button1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:paddingTop="5dp"
            android:paddingBottom="5dp"
            android:paddingLeft="5dp"
            android:paddingRight="5dp"
            android:text="Button1"
            />

        <ImageView
            android:layout_weight="1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:src="@drawable/img">
        </ImageView>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/txt1"
            android:layout_width="126dp"
            android:layout_height="match_parent"
            android:text="Hello"
            android:textColor="#FF0000"
            android:textSize="45dp">

        </TextView>

        <TextView
            android:id="@+id/txt2"
            android:layout_width="150dp"
            android:layout_height="match_parent"
            android:text="World"
            android:textColor="#0000FF"
            android:textSize="40dp">

        </TextView>

    </LinearLayout>
</LinearLayout>

developer.android.com/guide/topics/ui/layout/linear?hl=ko