我想过一些不那么优雅的方法来解决这个问题,但我知道我一定遗漏了什么。

我的onItemSelected立即启动,没有与用户进行任何交互,这是不希望的行为。我希望UI能够等到用户选择某样东西后再执行任何操作。

我甚至尝试在onResume()中设置监听器,希望能有所帮助,但它没有。

我怎样才能阻止它在用户可以触摸控件之前发射?

public class CMSHome extends Activity { 

private Spinner spinner;

@Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    // Heres my spinner ///////////////////////////////////////////
    spinner = (Spinner) findViewById(R.id.spinner);
    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
            this, R.array.pm_list, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(adapter);
    };

public void onResume() {
    super.onResume();
    spinner.setOnItemSelectedListener(new MyOnItemSelectedListener());
}

    public class MyOnItemSelectedListener implements OnItemSelectedListener {

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

     Intent i = new Intent(CMSHome.this, ListProjects.class);
     i.putExtra("bEmpID", parent.getItemAtPosition(pos).toString());
        startActivity(i);

        Toast.makeText(parent.getContext(), "The pm is " +
          parent.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show();
    }

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

当前回答

布尔标志或计数器的解决方案没有帮助我,因为在方向变化onItemSelected()调用“飞越”标志或计数器。

我子类化了android.widget.Spinner,并做了一些小的补充。相关部分如下。这个解决方案对我很有效。

private void setHandleOnItemSelected()
{
  final StackTraceElement [] elements = Thread.currentThread().getStackTrace();

  for (int index = 1; index < elements.length; index++)
  {
     handleOnItemSelected = elements[index].toString().indexOf("PerformClick") != -1; //$NON-NLS-1$

     if (handleOnItemSelected)
     {
        break;
     }
  }
}

@Override
public void setSelection(int position, boolean animate)
{
  super.setSelection(position, animate);

  setHandleOnItemSelected();
}

@Override
public void setSelection(int position)
{
  super.setSelection(position);

  setHandleOnItemSelected();
}

public boolean shouldHandleOnItemSelected()
{
  return handleOnItemSelected;
}

其他回答

mYear.setOnItemSelectedListener(new OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View arg1, int item, long arg3) {
                if (mYearSpinnerAdapter.isEnabled(item)) {

                }
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
            }
        });

只是为了补充使用onTouchListener来区分对setOnItemSelectedListener的自动调用(这是Activity初始化的一部分,等等)与实际用户交互触发的对它的调用之间的提示,在尝试了其他一些建议后,我做了以下工作,并发现它用最少的代码行就能很好地工作。

只需要为你的Activity/Fragment设置一个布尔字段:

private Boolean spinnerTouched = false;

然后在你设置你的旋转器的setOnItemSelectedListener之前,设置一个onTouchListener:

    spinner.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            System.out.println("Real touch felt.");
            spinnerTouched = true;
            return false;
        }
    });

    spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
    ...
         if (spinnerTouched){
         //Do the stuff you only want triggered by real user interaction.
        }
        spinnerTouched = false;

我创建了一个小工具方法来改变Spinner选择而不通知用户:

private void setSpinnerSelectionWithoutCallingListener(final Spinner spinner, final int selection) {
    final OnItemSelectedListener l = spinner.getOnItemSelectedListener();
    spinner.setOnItemSelectedListener(null);
    spinner.post(new Runnable() {
        @Override
        public void run() {
            spinner.setSelection(selection);
            spinner.post(new Runnable() {
                @Override
                public void run() {
                    spinner.setOnItemSelectedListener(l);
                }
            });
        }
    });
}

它禁用侦听器,更改选择,然后重新启用侦听器。

诀窍是调用对UI线程是异步的,所以必须在连续的处理程序中执行。

我用最简单的方法做到了:

private AdapterView.OnItemSelectedListener listener;
private Spinner spinner;

onCreate ();

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

listener = new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> adapterView, View view, int position, long l) {

            Log.i("H - Spinner selected position", position);
        }

        @Override
        public void onNothingSelected(AdapterView<?> adapterView) {

        }
    };

 spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
            spinner.setOnItemSelectedListener(listener);
        }

        @Override
        public void onNothingSelected(AdapterView<?> adapterView) {

        }
    });

Done

如果你需要在飞行中重新创建活动,例如:改变主题,一个简单的标志/计数器不会工作

使用onUserInteraction()函数检测用户活动,

参考资料:https://stackoverflow.com/a/25070696/4772917