Data not loading into my Spinner

I'm trying to load an array of data into a Spinner component and it's throwing a NullPointerException. The code I'm using is below and it all seems okay.

    Spinner spinner = (Spinner) findViewById(R.id.spinner);
    ArrayAdapter<?> spin_adapter = ArrayAdapter.createFromResource(
            this, R.array.letters_array, android.R.layout.simple_spinner_item);
    spin_adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(spin_adapter);

The string-array looks like this

<string-array name="letters_array">
    <item>A</item>
    <item>B</item>
    <item>C</item>
    <item>D</item>
    <item>E</item>
    <item>F</item>
    <item>G</item>
    <item>H</item>
    <item>I</item>
    <item>J</item>
    <item>K</item>
    <item>L开发者_JAVA百科</item>
    <item>M</item>
    <item>N</item>
    <item>O</item>
    <item>P</item>
    <item>Q</item>
    <item>R</item>
    <item>S</item>
    <item>T</item>
    <item>U</item>
    <item>V</item>
    <item>W</item>
    <item>X</item>
    <item>Y</item>
    <item>Z</item>
</string-array>

Is there a limit to the number of items in a Spinner or am I doing something else wrong?

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Try this:

ArrayAdapter<CharSequence> spin_adapter = ...

In which xml-File is your Array stored and where is it located?