android spinner fire event when same item selection is made

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迷失自我
迷失自我 2020-12-10 12:25

I want to fire a event when the same item is selected in spinner. Method

@Override
    public void onItemSelected(AdapterView parent, View arg1, int         


        
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5条回答
  • 2020-12-10 12:33

    Since my reputation is not high enough to comment directly on @Suat 's answer, I tried that method, it works like charm, but I'm not clear what the side effects could be. Something I want to add is, additional constructors should be added to avoid errors.

    public SpinnerTrigger(Context context, AttributeSet attrs, int defStyle)
    { super(context, attrs, defStyle); }
    
    public SpinnerTrigger(Context context, AttributeSet attrs){
    super(context,attrs);
    

    }

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  • 2020-12-10 12:38

    You can add a method name on your item selected METHOD

    Spinner `Spinner1`=(Spinner)findViewById(R.id.`declareid`)
    

    oBject has been declared for spinner

     @Override
            public void onItemSelected(AdapterView<?> parent, View arg1, int position,
                    long arg3) 
        {
        ItemOnChange();
           }
    
    private void ItemOnChange() {
    
            if(Spinner1.getSelectedItemPosition()>0){
            pd=ProgressDialog.show(this,"","Loading, Please wait .. ",true);
    
                final int spinner=Spinner1.getSelectedItemPosition();
    
    
                final Handler ThreadCallback=new Handler();
                final Runnable runInCityThread=new Runnable(){
                    public void run(){
                        fnBindspimmer2();
                        pd.dismiss();
                    }
    
                };
    
                new Thread(){
                    @Override public void run(){
    
                    Spinner2values();
                    ThreadCallback.post(runInCityThread);
                    }
    
                }.start();
            }
    
    
    
    }
    
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  • 2020-12-10 12:50

    use click listener to fulfill your requirement. as direct click listener on spinner doesn't supported so make a class extend spinner and over ride on click method and in this method do what you want to do.

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  • 2020-12-10 12:50

    Hopefully this help. I tried and it works

    /** Spinner extension that calls onItemSelected even when the selection is the same as its previous value */
        public class NDSpinner extends Spinner {
    
          public NDSpinner(Context context)
          { super(context); }
    
          public NDSpinner(Context context, AttributeSet attrs)
          { super(context, attrs); }
    
          public NDSpinner(Context context, AttributeSet attrs, int defStyle)
          { super(context, attrs, defStyle); }
    
          @Override public void
          setSelection(int position, boolean animate)
          {
            boolean sameSelected = position == getSelectedItemPosition();
            super.setSelection(position, animate);
            if (sameSelected) {
              // Spinner does not call the OnItemSelectedListener if the same item is selected, so do it manually now
              getOnItemSelectedListener().onItemSelected(this, getSelectedView(), position, getSelectedItemId());
            }
          }
    
          @Override public void
          setSelection(int position)
          {
            boolean sameSelected = position == getSelectedItemPosition();
            super.setSelection(position);
            if (sameSelected) {
              // Spinner does not call the OnItemSelectedListener if the same item is selected, so do it manually now
              getOnItemSelectedListener().onItemSelected(this, getSelectedView(), position, getSelectedItemId());
            }
          }
        }
    
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  • 2020-12-10 12:51

    i have found that old selection is kept at variable called mOldSelectedPosition in the hierarcy of the spinner. Spinner is using this value to check if the same item selected or not , and if it is the same , it ignores. If we dont wanna ignore this What i did is some dirty code using reflection.

    package com.aradiom.amc.nativecomponents;
    
    import java.lang.reflect.Field;
    
    import android.content.Context;
    import android.util.Log;
    import android.widget.Spinner;
    
    public class SpinnerTrigger extends Spinner {
    
    public SpinnerTrigger(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
    }
    
    @Override
    public void setSelection(int position, boolean animate) {
        ignoreOldSelectionByReflection();
        super.setSelection(position, animate);
    }
    
    private void ignoreOldSelectionByReflection() {
        try {
            Class<?> c = this.getClass().getSuperclass().getSuperclass().getSuperclass();
            Field reqField = c.getDeclaredField("mOldSelectedPosition");
            reqField.setAccessible(true);
            reqField.setInt(this, -1);
        } catch (Exception e) {
            Log.d("Exception Private", "ex", e);
            // TODO: handle exception
        }
    }
    
    @Override
    public void setSelection(int position) {
        ignoreOldSelectionByReflection();
        super.setSelection(position);
    }
    
    }
    

    This class will always invalidate the oldselection value , so that every time on click event gets triggered. It may not be perfect solution. Use with caution. :)

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