Android NullPointerException - Spinner onItemSelected `view` parameter is null after rotating

Question

Note: A limiting workaround from another, similar SO question\'s answer worked for me, but I am interested in finding a true solution. The workaround was to

Answer 1

you can use override method onSaveInstanceState() and onRestoreInstanceState(). or to stop calling onCreate() on screen rotation just add this line in your manifest xml android:configChanges="keyboardHidden|orientation"

note: your custom class must implements Parcelable example below.

@Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putParcelable("obj", myClass);
    }

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
 // TODO Auto-generated method stub
 super.onRestoreInstanceState(savedInstanceState);
 myClass=savedInstanceState.getParcelable("obj"));
}

public class MyClass implements Parcelable {
     private int mData;

 public int describeContents() {
     return 0;
 }

 /** save object in parcel */
 public void writeToParcel(Parcel out, int flags) {
     out.writeInt(mData);
 }

 public static final Parcelable.Creator<MyParcelable> CREATOR
         = new Parcelable.Creator<MyParcelable>() {
     public MyParcelable createFromParcel(Parcel in) {
         return new MyParcelable(in);
     }

     public MyParcelable[] newArray(int size) {
         return new MyParcelable[size];
     }
 };

 /** recreate object from parcel */
 private MyParcelable(Parcel in) {
     mData = in.readInt();
 }


}

Answer 2

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

adapterView is referenced to Spinner, not the item you clicked, you should cast the "view" parameter instead.

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@Rock Lee After rotated the layout would be refresh, you should resetup the spinner in some callback function like onConfigurationChanged(Configuration newConfig), Android listview disappears after screen rotation