Question

我试图找出如何将两个微调器的值相乘并在TextView中显示答案。但是，代码会编译，应用程序在运行时会关闭。下面的代码是我目前使用的，但是，它不起作用。感谢。

    spinnerStep1 =(Spinner) findViewById(R.id.step_1_spinner);
    Integer[] step1 = new Integer[]{0,1,2,3,4,5};
    ArrayAdapter<Integer> adapter1 = new ArrayAdapter<Integer>   (this,R.layout.spinner_item, step1);
    spinnerStep1.setAdapter(adapter1);
    spinnerStep1.setOnItemSelectedListener(this);


    spinnerStep2 =(Spinner) findViewById(R.id.step_2_spinner);
    Integer[] step2 = new Integer[]{0,1,2,3,4,5};
    ArrayAdapter<Integer> adapter2 = new ArrayAdapter<Integer>(this,R.layout.spinner_item, step2);
    spinnerStep2.setAdapter(adapter2);
    spinnerStep2.setOnItemSelectedListener(this);

    drakeAnswer = (TextView) findViewById(R.id.drake_answer);

}


@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {

    String myStr1 = spinnerStep1.getSelectedItem().toString();
    String myStr2 = spinnerStep2.getSelectedItem().toString();
    int myAnswer = 0;
    try {
        myAnswer = Integer.parseInt(myStr1) * Integer.parseInt(myStr2);
    }catch(NumberFormatException nfe) {

    }
    drakeAnswer.setText(myAnswer);


}

Answer 1

最佳做法是从onItemSelected方法中再次获取两个微调器和文本视图，您还需要确保在setText方法中设置字符串值：

@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
    Spinner spinnerStep1 = (Spinner)findViewById(R.id.step_1_spinner);
    Spinner spinnerStep2 = (Spinner)findViewById(R.id.step_2_spinner);
    String myStr1 = spinnerStep1.getSelectedItem().toString();
    String myStr2 = spinnerStep2.getSelectedItem().toString();
    int myAnswer = 0;
    try {
        myAnswer = Integer.parseInt(myStr1) * Integer.parseInt(myStr2);
    } catch(NumberFormatException nfe) {
        Log.e("Error", "Failed to multiply invalid non-numbers");
    }
    TextView drakeAnswer = (TextView)findViewById(R.id.drake_answer); 
    drakeAnswer.setText("" + myAnswer);
}

Answer 2

问题可能出在这一行

drakeAnswer.setText(myAnswer);

TextView的setText方法被重载，其中之一是：

setText(int resid)

您正在调用的是哪一个，并且可能没有像您传递的那样的resId。如果您想在 TextView 中编写 myAnswer ，请将其作为字符串传递：

drakeAnswer.setText(myAnswer);

如何在Android中乘以微调器的值

2 个答案: