小编Jac*_*cci的帖子

我在android studio中构建了一个转换器,每次按下转换按钮时,距离部分(活动)都会崩溃.该应用程序表示特定活动已停止工作,应用程序将返回主要活动.它没有在android studio中显示任何错误,我认为我的问题可能是使用来自微调器的int pos但我不确定.这是我要完成的最后一个元素.请帮忙.下面是java后跟xml.

    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main4);

    spinnerFrom = (Spinner)findViewById(R.id.spinner1);
    ArrayAdapter<CharSequence> adapterFrom = ArrayAdapter.createFromResource(this, R.array.distance_array, android.R.layout.simple_spinner_item);
    adapterFrom.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinnerFrom.setAdapter(adapterFrom);
    spinnerFrom.setOnItemSelectedListener(this);

    spinnerTo = (Spinner)findViewById(R.id.spinner2);
    ArrayAdapter<CharSequence> adapterTo = ArrayAdapter.createFromResource(this, R.array.distance_array, android.R.layout.simple_spinner_item);
    adapterTo.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinnerTo.setAdapter(adapterTo);
    spinnerTo.setOnItemSelectedListener(this);

}   
public void convert(View view){
    double value = new Double(distance.getText().toString());
    from = spinnerFrom.getSelectedItemPosition();
    to = spinnerTo.getSelectedItemPosition();

    if(from == 0){
        if(to == 1)
            value = UnitConverter.feetToMiles(value);
        else if (to == 2)
            value = UnitConverter.feetToMeters(value);
        else if(to == 3)
            value = UnitConverter.feetToYards(value);
        else
            value = value;
    }else …