java无法从片段中获取上下文

Question

我试图从活动中调用片段方法，但在该方法中使用getActivity()设置适配器上下文时，我遇到了空指针异常：

片段法

public void fragmentMethod() {
            String[] names = new String[]{"name1", "name2", "name3"};
            String[] values = new String[]{value1, value2, value3};
            adapter = new MyArrayAdapter(getActivity(), names, values);
            setListAdapter(adapter);
}

适配器

public class MyArrayAdapter extends ArrayAdapter<String> {

    private final Context context;
    private final String[] names;
    private final String[] values;

    public MyArrayAdapter (Context context, String[] names, String[] values) {
        super(context, R.layout.rowlayout, values);
        this.context = context;
        this.names = names;
        this.values = values;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ...
    }

}

从活动调用片段方法

public void activityMethod() {
    FragmentName  test= new FragmentName();
    test.fragmentMethod();
}

我尝试过很多不同的事情，但我在这里不知所措。。。如果我在尝试做的事情上根本错误，请让我知道，因为我是新手。谢谢!

编辑：堆栈跟踪

（Inventory是片段类）

这是在单击调用activityMethod()的imageview之后

06-04 19:55:17.976    1147-1147/company.com.myapp E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
        at 安卓.widget.ArrayAdapter.init(ArrayAdapter.java:310)
        at 安卓.widget.ArrayAdapter.<init>(ArrayAdapter.java:128)
        at company.com.myapp.MyArrayAdapter.<init>(MyArrayAdapter.java:18)
        at company.com.myapp.Inventory.createList(Inventory.java:105)
        at company.com.myapp.MainActivity.newDay(MainActivity.java:177)
        at company.com.myapp.MainActivity$2.onClick(MainActivity.java:91)
        at 安卓.view.View.performClick(View.java:4240)
        at 安卓.view.View$PerformClick.run(View.java:17721)
        at 安卓.os.Handler.handleCallback(Handler.java:730)
        at 安卓.os.Handler.dispatchMessage(Handler.java:92)
        at 安卓.os.Looper.loop(Looper.java:137)
        at 安卓.app.ActivityThread.main(ActivityThread.java:5103)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:525)
        at com.安卓.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
        at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:553)
        at dalvik.system.NativeStart.main(Native Method)

Answer 1

在onActivityCreated()或onAttach()内这样做