数组的Drawable路径返回空值

Question

我创建了一个整型值的数组，这些整型值是一个图片对象的路径ID，就像这样

int[] picItems = {R.drawable.pic_one, R.drawable.pic_two, R.drawable.pic_three};

然后，picItem的数组是空的。我想要能够从一个索引里取到这些值然后用它作为背景，就像这样：

relative.setBackgroundResource(picItems[index]);

现在，如果我用上边的代码然后设置参数字段为R.drawable.pic_one，这是可以的。但是，当我进行申明然后实例化整形数组picItems，我得到了一个空指针的异常。我必须仔细的检查一下，而且还有一个简单的错误，但是如果有谁能够随意的就指出它来，我会非常感谢的，谢谢。！
我已经试了很多种不同的方法来声明和实例化这个数组。尽管在实例化之后这个数组仍然是空的，当想要用的时候还是有一个错误（我为了能够捕获到错误用了一个if语句）
下边是一小段代码

public class Snow extends Activity{
        int[] picItems;
        RelativeLayout relative;
        SharedPreferences sp;
        int checkedItem = 0;

        @Override
        public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

            picItems = new int[]{R.drawable.pic_one, R.drawable.pic_two, R.drawable.pic_three};
            sp = getPreferences(MODE_PRIVATE);
            checkedItem = sp.getInt("picture", 0);
            if (!(picItems == null) || !(picItems.equals(null))){
            Toast.makeText(getApplicationContext(), "Array is null for some reason", Toast.LENGTH_SHORT).show();
        }else{
             relative.setBackgroundResource(picItems[checkedItem]);
        }//end of if
            ...} ...}

这是Logcat Output:

11-20 19:00:27.363: E/AndroidRuntime(18311): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.app.Snow/com.app.snow.Snow}: java.lang.NullPointerException
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1821)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1842)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at android.app.ActivityThread.access$1500(ActivityThread.java:132)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1038)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at android.os.Handler.dispatchMessage(Handler.java:99)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at android.os.Looper.loop(Looper.java:150)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at android.app.ActivityThread.main(ActivityThread.java:4263)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at java.lang.reflect.Method.invokeNative(Native Method)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at java.lang.reflect.Method.invoke(Method.java:507)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at dalvik.system.NativeStart.main(Native Method)
    11-20 19:00:27.363: E/AndroidRuntime(18311): Caused by: java.lang.NullPointerException
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at com.app.snow.Snow.onCreate(Snow.java:54)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072)
    11-20 19:00:27.363: E/AndroidRuntime(18311):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1785)

Answer 1

我怎么感觉我被愚弄了。picItems是正常的，相对的是空，在onCreate()初始化它

relative = (RelativeLayout) findViewById(R.id.layout);