android, NumberPicker 越界

Question

NumberPicker serviceWheel = (NumberPicker) findViewById(R.id.serviceSelector);
serviceWheel.setMaxValue(serviceArray.length());
String[] profiles = new String[serviceArray.length()];
for (int i = 0; i < serviceArray.length(); i++){
   JSONObject profileObject = serviceArray.getJSONObject(i);
   profiles[i] = profileObject.getString("description");
}
serviceWheel.setDisplayedValues(profiles);
serviceWheel.setWrapSelectorWheel(false);

 E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.ArrayIndexOutOfBoundsException: length=3; index=3
            at android.widget.NumberPicker.ensureCachedScrollSelectorValue(NumberPicker.java:1756)
            at android.widget.NumberPicker.incrementSelectorIndices(NumberPicker.java:1722)
            at android.widget.NumberPicker.scrollBy(NumberPicker.java:1097)
            at android.widget.NumberPicker.onTouchEvent(NumberPicker.java:880)
            at android.view.View.dispatchTouchEvent(View.java:7565)

serviceArray 是一个JSONArray，长度为3。我试图在实例化数组时添加填充 ( serviceArray.length() + 1 ) 但这导致在显示 Activity 之前失败。 NumberPicker 显示正常，但是当我滚动到数组的最后一个条目时，它因此错误而崩溃。我的代码中没有引用代码行

Answer 1

由此改变:

serviceWheel.setMaxValue(serviceArray.length());

为此:

serviceWheel.setMaxValue(serviceArray.length() - 1);