在Activity之外构建AlerDialog(RecyclerView.Viewholder)

Question

我正在使用RecyclerView,并且只要长按RecyclerView中的项目,就想打开AlertDialog.

在RecyclerView的ViewHolder中,我实现了clicklistener

 @Override
    public boolean onLongClick(View v) {

        //Open Alert dialog to delete item

        AlertDialog.Builder alert = new AlertDialog.Builder(context);

        ...

}

我可以在这里阅读:http://goo.gl/Kd1c7i一个需要通过"MyActivity.this"到AlertDialog.Builder构造函数,但由于ViewHolder是RecyclerView适配器的静态部分,我不能引用"MyActivity.这个".因此我仍然得到错误:

android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application

那么如何从不扩展Activity的类创建AlertDialog？

@Edit:更多代码以获取更多信息:

这是我的RecyclerView Adapter构造函数:

RecyclerViewCourseAdapter(ArrayList<Course> courses, Context context) {
    this.context = context;
    if (courses == null) {
        throw new IllegalArgumentException("courses ArrayList must not be null");
    }

    mCourseArrayList = courses;
}

我将给定的上下文存储为Adapter类中的private:

private Context context;

这是我的ViewHolder:

public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener,View.OnLongClickListener {

    //Initialize views in Viewholder
    TextView mTextViewFirst;
    TextView mTextViewSecond;
    ImageView mImageView;
    TextView mEndPercentageTextView;

    //Context to refer to app context (for intent, dialog etc)
    Context context;

    //Adapter to notifiy data set changed
    RecyclerViewCourseAdapter mCourseAdapter;


    public ViewHolder(View itemView, Context context, RecyclerViewCourseAdapter mCourseAdapter) {

        super(itemView);
        this.context = context;
        this.mCourseAdapter = mCourseAdapter;
        itemView.setOnClickListener(this);
        itemView.setOnLongClickListener(this);
        mTextViewFirst = (TextView) itemView.findViewById(R.id.course_firstLine);
        mTextViewSecond = (TextView) itemView.findViewById(R.id.course_secondLine);
        mImageView = (ImageView) itemView.findViewById(R.id.icon);
        mEndPercentageTextView = (TextView) itemView.findViewById(R.id.end_percentage_textview);
    }

这就是我创建视图的方式:

public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    //Inflate layout
    View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_course, parent, false);
    ViewHolder vh = new ViewHolder(itemView, context, this);

    return vh;
}

所以我使用适配器中存储的上下文创建我的ViewHolder.

如果事情仍unlcear,这里是我的全班同学: https://github.com/Tak3r07/UniHelper/blob/master/app/src/main/java/com/tak3r07/CourseStatistics/RecyclerViewCourseAdapter.java

Answer 1

每个人View都有一个背景,改变:

AlertDialog.Builder alert = new AlertDialog.Builder(context);

至

AlertDialog.Builder alert = new AlertDialog.Builder(v.getContext());

有关详细信息,请参阅文档:

http://developer.android.com/reference/android/view/View.html#getContext()