訓練50日目（Android7-3)

さて午後。
＃「onActivityResult()」は後で調べよう。

★ページ遷移＋計算
出来たには出来たけど、普通すぎる、、、
[MainActivity.java]

public class MainActivity extends Activity {
  EditText et1;
  EditText et2;
  Button btn1;
  Button btn2;
  Button btn3;
  Button btn4;

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

  private void findView() {
    et1 = (EditText)findViewById(R.id.editText1);
    et2 = (EditText)findViewById(R.id.editText2);
    btn1 = (Button)findViewById(R.id.button1);
    btn2 = (Button)findViewById(R.id.button2);
    btn3 = (Button)findViewById(R.id.button3);
    btn4 = (Button)findViewById(R.id.button4);
  }

  private void addEvent() {
    btn1.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) { a(1); }
    });
    btn2.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) { a(2); }
    });
    btn3.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) { a(3); }
    });
    btn4.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) { a(4); }
    });    
  }

  public void a(int mathMarkNum){
    //数値を取得
    int num1 = Integer.parseInt(et1.getText().toString());
    int num2 = Integer.parseInt(et2.getText().toString());
    int sum = 0;
    switch(mathMarkNum){
      case 1:
        sum = num1+num2;
        break;
      case 2:
        sum = num1-num2;
        break;
      case 3:
        sum = num1*num2;
        break;
      case 4:
        sum = num1/num2;
        break;
    }
    Intent i = new Intent(MainActivity.this, ResultActivity.class);
    i.putExtra("NUM", sum+"");
    startActivity(i);
  }
}

[ResultActivity.java]

public class ResultActivity extends Activity {

  TextView tv;
  Button bt;

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

    findView();
    addEvent();
  }

  private void findView() {
    tv = (TextView)findViewById(R.id.textView1);
    bt = (Button)findViewById(R.id.button1);
    Intent i= this.getIntent();
    String num = i.getStringExtra("NUM");
    tv.setText(num);
  }

  private void addEvent() {
    bt.setOnClickListener(new OnClickListener() {

      @Override
      public void onClick(View v) {
        finish();
      }
    });
  }
}

あれ、ボタンを1まとめに出来るんだ・・・

public class MainActivity extends Activity implements OnClickListener{
  EditText et1;
  EditText et2;
  Button btAdd;
  Button btSub;
  Button btMul;
  Button btDiv;
  int ans;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    findView();
  }

  private void findView() {
    et1=(EditText)findViewById(R.id.editText1);
    et2=(EditText)findViewById(R.id.editText2);
    btAdd=(Button)findViewById(R.id.button1);
    btAdd.setOnClickListener(this);
    btSub=(Button)findViewById(R.id.button2);
    btSub.setOnClickListener(this);
    btMul=(Button)findViewById(R.id.button3);
    btMul.setOnClickListener(this);
    btDiv=(Button)findViewById(R.id.button4);
    btDiv.setOnClickListener(this);
  }

  @Override
  public void onClick(View v) {
    
    int a=Integer.parseInt(et1.getText().toString());
    int b=Integer.parseInt(et2.getText().toString());
    switch(v.getId()){
    case R.id.button1:
      ans=a+b;
      break;
    case R.id.button2:
      ans=a-b;
      break;
    case R.id.button3:
      ans=a*b;
      break;
    case R.id.button4:
      ans=a/b;
      break;
    }
    
    Intent i=new Intent(MainActivity.this,ResultActivity.class);
    i.putExtra("ans", ans);
    startActivity(i);
  }

}