Question

我有一个问题。我创建了微调器，所有应用程序都运行而不会崩溃，但它不会改变int price的值，setText也不会工作

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

Button calculateBtn;
EditText userEcts;
TextView ectsPrice;
TextView summary;
Spinner courses;
String cors;
int price = 200;

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

    userEcts = (EditText) findViewById(R.id.ects_input);
    summary = (TextView) findViewById(R.id.text_summary);
    courses = (Spinner) findViewById(R.id.course_spinner);

    calculateBtn = (Button) findViewById(R.id.calculate);
    calculateBtn.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            //When the button is clicked, call the calculate method.
            calculate();
        }
    });

    final String[] courseArray = new String[4];
    {
        courseArray[0] = "Preddiplomski studij Menadžment";
        courseArray[1] = "Preddiplomski studij Promet";
        courseArray[2] = "Preddiplomski Upravni studij";
        courseArray[3] = "Specijalistički studij Menadžment";
    }

    ArrayAdapter courseAdapter = new ArrayAdapter(this,
            android.R.layout.simple_spinner_item, courseArray);
    courseAdapter.setDropDownViewResource(android.R.layout.select_dialog_singlechoice);
    courses.setAdapter(courseAdapter);

    courses.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener(){

        public void onItemSelected(AdapterView<?> parent,
                                   View view, int pos, long id) {

            //Get item from Spinner and store in string conductorSize........
            cors = parent.getItemAtPosition(pos).toString();
            if (cors.equals(0)) {
                ectsPrice.setText("200");
                price = 200;
            } else if (cors.equals(1)) {
                ectsPrice.setText("250");
                price = 250;
            } else if (cors.equals(2)) {
                ectsPrice.setText("300");
                price = 300;
            } else if (cors.equals(3)) {
                ectsPrice.setText("350");
                price = 350;
            } else {
                //Do nothing
            }
        }

        public void onNothingSelected(AdapterView parent) {
            // Do nothing.
        }
    });
}

public void calculate() {
    //gets entered text from the EditText,and convert to integers.
    if (!TextUtils.isEmpty(userEcts.getText().toString())) {
        Double ects = Double.parseDouble(userEcts.getText().toString());
        //do the calculation
        Double calculatedPrice = ects * price;
        //set the value to the TextView, to display on screen.
        summary.setText("Ukupno za platit: " + Double.toString(calculatedPrice) + "kn");
    } else {
        Toast.makeText(this, "Niste unijeli broj bodova", Toast.LENGTH_SHORT).show();
    }
}

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

}

因此，在选择位置0上的项目时，我想将文本设置为特定文本，并更改价格。有人可以帮忙吗？

Answer 1

使用位置编号检查条件。

String[] courseArray = new String[4];
    {
        courseArray[0] = "Preddiplomski studij Menadžment";
        courseArray[1] = "Preddiplomski studij Promet";
        courseArray[2] = "Preddiplomski Upravni studij";
        courseArray[3] = "Specijalistički studij Menadžment";
    }

    ArrayAdapter courseAdapter = new ArrayAdapter(this,
            android.R.layout.simple_spinner_item, courseArray);
    courseAdapter.setDropDownViewResource(android.R.layout.select_dialog_singlechoice);
    courses.setAdapter(courseAdapter);

    courses.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener(){

        public void onItemSelected(AdapterView<?> parent,
                                   View view, int pos, long id) {

            //Get item from Spinner and store in string conductorSize........
            cors = parent.getItemAtPosition(pos).toString();
            if (cors.equals(courseArray[0])) {
                ectsPrice.setText("200");
                price = 200;
            } else if (cors.equals(courseArray[1])) {
                ectsPrice.setText("250");
                price = 250;
            } else if (cors.equals(courseArray[2])) {
                ectsPrice.setText("300");
                price = 300;
            } else if (cors.equals(courseArray[3])) {
                ectsPrice.setText("350");
                price = 350;
            } else {
                //Do nothing
            }
        }

        public void onNothingSelected(AdapterView parent) {
            // Do nothing.
        }
    });
}

Answer 2

使用开关声明：

public void onItemSelected(AdapterView<?> parent,
                               View view, int pos, long id) {

        switch(pos){
            case 0:
              ectsPrice.setText("200");
              price = 200;
              break;
            case 1:
              ectsPrice.setText("250");
              price = 250;
              break;
            case 2:
              ectsPrice.setText("300");
              price = 300;
              break;
            case 3:
              ectsPrice.setText("350");
              price = 350;
              break;
        }
  }

有条件的微调器

2 个答案: