안드로이드 스튜디오 자바 문법

안드로이드 스튜디오 자바 문법

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좋아요

1) 형식 변환하기

Button button1, button2,button3, button4, button5; TextView tv1, tv2, tv3, tv4, tv5; Integer var1; float var2; double var3; char var4; String var1Str, var2Str, var3Str, var4Str, var5Str; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); button1 = (Button) findViewById(R.id.button1); button2 = (Button) findViewById(R.id.button2); button3 = (Button) findViewById(R.id.button3); button4 = (Button) findViewById(R.id.button4); button5 = (Button) findViewById(R.id.button5); tv1 = (TextView) findViewById(R.id.textView); tv2 = (TextView) findViewById(R.id.textView2); tv3 = (TextView) findViewById(R.id.textView3); tv4 = (TextView) findViewById(R.id.textView4); tv5 = (TextView) findViewById(R.id.textView5); button1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { var1 = 10; var1Str = var1.toString(); tv1.setText(var1Str); } }); button2.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { var2 = 10.1f; var2Str = Float.toString(var2); tv2.setText(var2Str); } }); button3.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { var3 = 10.2; var3Str = Double.toString(var3); tv3.setText(var3Str); } }); button4.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { var4 = '안'; var4Str = Character.toString(var4); tv4.setText(var4Str); } }); button5.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { var5Str = "안드로이드"; tv5.setText(var5Str); } }); } }

2) editText와 if 조건문 사용

Button button1, button2; EditText edit1; TextView tv1; Integer count; String num1Str; ImageView imageView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); button1 = (Button) findViewById(R.id.button1); edit1 = (EditText) findViewById(R.id.edit1); tv1 = (TextView) findViewById(R.id.textView); imageView = (ImageView) findViewById(R.id.image); button1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // int count = 85; num1Str = edit1.getText().toString(); // 에디트 텍스트에서 데이터 가져오기 count = Integer.parseInt(num1Str); // 문자열을 정수로 변환하기 if (count == -99) { tv1.setText("종료"); imageView.setImageResource(0); } else if (count >= 90) { tv1.setText("합격 (장학생)"); imageView.setImageResource(R.drawable.nnice); } else if (count >= 60) { tv1.setText("합격"); imageView.setImageResource(R.drawable.nice); } else { tv1.setText("불합격"); imageView.setImageResource(R.drawable.bad); } } }); } }

2-2) 위의 코드를 switch문으로 표현하기

button1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // int count = 85; num1Str = edit1.getText().toString(); // 에디트 텍스트에서 데이터 가져오기 count = Integer.parseInt(num1Str); // 문자열을 정수로 변환하기 if (count == -99) { tv1.setText("if-종료"); imageView.setImageResource(0); } else if (count >= 90) { tv1.setText("if-합격 (장학생)"); imageView.setImageResource(R.drawable.nnice); } else if (count >= 60) { tv1.setText("if-합격"); imageView.setImageResource(R.drawable.nice); } else { tv1.setText("if-불합격"); imageView.setImageResource(R.drawable.bad); } } }); button2.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { num1Str = edit1.getText().toString(); count = Integer.parseInt(num1Str); var1 = (count / 10) * 10; switch(var1){ case 100: case 90: tv2.setText("switch-합격(장학생)"); imageView.setImageResource(R.drawable.nnice); break; case 80: case 70: case 60: tv2.setText("switch-합격"); imageView.setImageResource(R.drawable.nice); break; default: tv2.setText("switch-불합격"); imageView.setImageResource(R.drawable.bad); } } }); } }

3) 반복문을 for문, while문으로 표현하기

Button button1, button2; TextView tv1, tv2; Integer var1, j; String intTotal, intTotal2; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); button1 = (Button) findViewById(R.id.button1); button2 = (Button) findViewById(R.id.button2); tv1 = (TextView) findViewById(R.id.textView); tv2 = (TextView) findViewById(R.id.textView2); button1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { int one[] = new int[3]; intTotal = ""; for (int i=0; i

" + one[i]; } tv1.setText("for문 수행 후 출력

"+intTotal); } }); button2.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { int one[] = new int[3]; intTotal2=""; int j=0; while (j

" + one[j]; j++; } tv2.setText("while문 수행 후 출력

" + intTotal2); } }); } }

4) 함수 이용하여 표현하기

public class MainActivity extends AppCompatActivity { Button button1, button2; TextView tv1, tv2; static Integer var = 100; String tempStr, tempStr2; static Integer addFOO(Integer num1, Integer num2) { //함수 Integer hap; hap = num1 + num2 + var; return hap; } static Integer subFOO(Integer num1, Integer num2) { //함수 Integer hap; hap = num1 - num2 + var; return hap; } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); button1 = (Button) findViewById(R.id.button1); button2 = (Button) findViewById(R.id.button2); tv1 = (TextView) findViewById(R.id.textView); tv2 = (TextView) findViewById(R.id.textView2); button1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Integer sum = addFOO(10, 20); tempStr = sum.toString(); tv1.setText("addFOO 출력

"+tempStr); } }); button2.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Integer sub = subFOO(10, 20); tempStr2 = sub.toString(); tv2.setText("subFOO 출력

"+tempStr2); } }); } }

from http://zoo-coding.tistory.com/3 by ccl(A) rewrite - 2021-12-30 04:02:25