android - Android spinner 只听一次？

Question

我试图使用微调器在两个布局之间切换，我使用 setContentView 来做到这一点。但是，一旦我用微调器进行了选择，它似乎就像微调器停止“听”一样。

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_add_exercise);
    getSupportActionBar().setHomeButtonEnabled(true);
            initSpinnerType();}

    public void initSpinnerType()
{
    spinnerType = (Spinner) findViewById(R.id.spinner_type_of_training);
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
            R.array.trainingtype_array, android.R.layout.simple_spinner_item);

    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

    spinnerType.setAdapter(adapter);

    spinnerType = (Spinner) findViewById(R.id.spinner_type_of_training);
    spinnerType.setOnItemSelectedListener(this);

}
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
    if(items[position].equals("Static"))
    {
        setContentView(R.layout.add_exercise_static);
        spinnerType = (Spinner)findViewById(R.id.spinner_type_of_training);
        spinnerType.setSelection(1,true);
        System.out.println("static");

        //button.setVisibility(View.VISIBLE);
    }

    else if(items[position].equals("Dynamic"))
    {
        setContentView(R.layout.add_exercise_static);
        spinnerType = (Spinner)findViewById(R.id.spinner_type_of_training);
        spinnerType.setSelection(2,true);
        System.out.println("dynamic");
    }
    else
    {
        System.out.println("cardio");
        //button.setVisibility(view.VISIBLE);
        setContentView(R.layout.activity_add_exercise);

    }
 }