Adapter for a spinner makes NullPointerException

问题

I made an array list in one of my value's folder, now when i want to adapt it to the spinner by retrieving it from the source folder it says NullPointerException:

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

    ArrayAdapter adapter = ArrayAdapter.createFromResource(this,R.array.worker,android.R.layout.simple_list_item_1);
    spinner.setAdapter(adapter);
    spinner.setOnItemSelectedListener(this);

Messages in LogCat:

 Caused by: android.content.res.Resources$NotFoundException: String array resource ID #0x7f090001 at android.content.res.Resources.getStringArray(Resources.java:527) at com.example.hay.myapplication.UserCreatingActivity.onCreate(UserCreatingActivity‌.java:46) at android.app.Activity.performCreate(Activity.java:5990) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:227

回答1:

Try giving the ArrayAdapter a type:

ArrayAdapter<String> adapter = ArrayAdapter.createFromResource(this, R.array.worker, android.R.layout.simple_spinner_item);

回答2:

since you have the exception:

 `Caused by: android.content.res.Resources$NotFoundException: String array resource ID #0x7f090001 at

I see that your problem is the last value inside the createFromResource() method:

 ArrayAdapter adapter = ArrayAdapter.createFromResource(this,R.array.worker,android.R.layout.simple_list_item_1);

the last value must be the array:

 ArrayAdapter adapter = ArrayAdapter.createFromResource(this,android.R.layout.simple_list_item_1,R.array.worker);

回答3:

Try to flip the two last parameters in createFromRessource:

Replace:

ArrayAdapter adapter = ArrayAdapter.createFromResource(this,R.array.worker,android.R.layout.simple_list_item_1);

By:

ArrayAdapter<String> adapter = ArrayAdapter.createFromResource(this, android.R.layout.simple_list_item_1, R.array.worker);

In your code:

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

    ArrayAdapter<String> adapter = ArrayAdapter.createFromResource(this, android.R.layout.simple_list_item_1, R.array.worker);
    spinner.setAdapter(adapter);
    spinner.setOnItemSelectedListener(this);

回答4:

change

 attr.xml