Question

在微调器中选择任何类型时，微调器有一个乐队类型的数组列表，它将显示一个吐司，当点击微调器时，toast没有显示，代码没有显示任何错误？任何想法为什么？

    String spinnerSelection = null;
    Spinner spinner = null;

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



       ArrayAdapter<String> adapter = new ArrayAdapter<>(
                this, android.R.layout.simple_spinner_item, spinnerContent);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);


        spinner = (Spinner) findViewById(R.id.spinner);
        spinner.setAdapter(adapter);



        Button button = (Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {



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

            Toast.makeText( getBaseContext(),"Hell Yeah", Toast.LENGTH_SHORT).show();
        }
    }
    public void onNothingSelected(AdapterView<?> arg0) {
    }
}

Answer 1

不要忘记在微调器中添加点击侦听器

    spinner.setOnItemClickListener(this);

Answer 2

您正在按钮上添加setOnClickListener（）。将setOnItemClickListener（）添加到您的微调器。

Answer 3

您需要为@Override和onItemSelected(...)函数添加onNothingSelected(...)。

确保在微调器上设置一个侦听器： spinner.setOnItemClickListener(this);

修改

public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {
    MediaPlayer myMusic;
    int paused;


    public void play(View view) {
        if (myMusic == null) {
            myMusic = MediaPlayer.create( this, R.raw.fast_and_cold );
            myMusic.start();


        }
    }


    public void stop(View view) {
        myMusic.reset();
        myMusic = null;
    }



    String spinnerSelection = null;
    Spinner spinner = null;

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



        final List<String> spinnerContent = new ArrayList<>();
        spinnerContent.add("Black Metal");
        spinnerContent.add("Death Metal");
        spinnerContent.add("Thrash Metal");
        spinnerContent.add("Heavy Metal");



        ArrayAdapter<String> adapter = new ArrayAdapter<>(
            this, android.R.layout.simple_spinner_item, spinnerContent);

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


        spinner = (Spinner) findViewById(R.id.spinner);
        spinner.setAdapter(adapter);
        spinner.setOnItemSelectedListener(this); // add this line



        Button button = (Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {





    }

    @Override // add this line
    public void onItemSelected(AdapterView<?>parent, View v, int position, long id) {


            Toast.makeText( getBaseContext(),"Show your Devil Horns !!", Toast.LENGTH_SHORT).show();

    }

    @Override // add this line
    public void onNothingSelected(AdapterView<?> arg0) {

    } 

}

旋转器的吐司没有显示

3 个答案: