2장. 뷰와 레이아웃

1. TextView 전송

1-1. activity_main.xml

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

    <RelativeLayout
        android:id="@+id/inputlayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/buttonLayout"
        android:layout_alignParentTop="true">

        <EditText
            android:id="@+id/inputMessage"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_above="@+id/inputCount"
            android:layout_marginLeft="10dp"
            android:layout_marginRight="10dp"
            android:cacheColorHint="#00000000"
            android:gravity="top"
            android:listSelector="#00000000"
            android:maxLength="80"
            android:textSize="48sp" />

        <!--  글자 수를 표시하는 TextView -->
        <TextView
            android:id="@+id/inputCount"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentEnd="true"
            android:layout_alignParentBottom="true"
            android:text="0 / 80 bytes" />
    </RelativeLayout>

    <!-- 여기에 전송, 닫기 버튼 포함하는 LinearLayout 작성 -->
    <LinearLayout
        android:id="@+id/buttonLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="21dp"
        android:orientation="horizontal">

        <Button
            android:id="@+id/sendButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="50dp"
            android:layout_weight="1"
            android:text="Send" />

        <Button
            android:id="@+id/closeButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="50dp"
            android:layout_weight="1"
            android:text="Close" />
    </LinearLayout>
</RelativeLayout>

 

1-2. MainActivity.java

public class MainActivity extends AppCompatActivity {
    EditText inputMessage;
    TextView inputCount;

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

        inputMessage = findViewById(R.id.inputMessage);
        inputCount = findViewById(R.id.inputCount);


        Button sendButton = findViewById(R.id.sendButton);
        sendButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                String message = inputMessage.getText().toString();
                Toast.makeText(getApplicationContext(), "전송할 메시지\n\n" + message, Toast.LENGTH_LONG).show();
            }
        });

        Button closeButton = findViewById(R.id.closeButton);
        closeButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                finish();
            }
        });

        TextWatcher watcher = new TextWatcher() {
            public void onTextChanged(CharSequence str, int start, int before, int count) {
                byte[] bytes = null;
                try {
                    bytes = str.toString().getBytes("KSC5601");
                    int strCount = bytes.length;
                    inputCount.setText(strCount + " / 80바이트");
                } catch(UnsupportedEncodingException ex) {
                    ex.printStackTrace();
                }
            }
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {}

            public void afterTextChanged(Editable strEditable) {
                String str = strEditable.toString();
                try {
                    byte[] strBytes = str.getBytes("KSC5601");
                    if(strBytes.length > 80) {
                        strEditable.delete(strEditable.length()-2, strEditable.length()-1);
                    }
                } catch(Exception ex) {
                    ex.printStackTrace();
                }
            }
        };

        inputMessage.addTextChangedListener(watcher);
    }
}