尝试在空对象引用（片段）上调用虚拟方法“android.content.res.Resources$Theme android.content.Context.getTheme()”

Question

这是片段的java文件代码：

@SuppressLint({"NewApi", "ResourceAsColor"})
public void createCardView(String id, String date, final String order) {
    flag = true;
    cardView = new CardView(context);
    cardView.setLayoutParams(layoutParamsCard);
    cardView.setElevation(5);
    relativeLayout = new RelativeLayout(context);
    relativeLayout.setLayoutParams(layoutParamsRelative);
    textView = new TextView(context);
    orderID = new TextView(context);
    textView.setLayoutParams(layoutParamsTextView);
    textView.setText("Order ID:");
    textView.setTextColor(Color.parseColor("#1e1e1e"));
    textView.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
    orderID.setLayoutParams(layoutParamsTextViewID);
    orderID.setText(id);
    orderID.setTextColor(Color.parseColor("#646464"));
    orderID.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
    orderDate = new TextView(context);
    orderDate.setText(date);
    orderDate.setLayoutParams(layoutParamsOrderDate);
    viewOrder = new Button(context);
    viewOrder.setText("View Order");
    viewOrder.setTextColor(Color.parseColor("#ffffff"));
    viewOrder.setBackgroundColor(Color.parseColor("#326432"));
    viewOrder.setLayoutParams(layoutParamsViewOrder);
    viewOrder.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            LayoutInflater inflater = getLayoutInflater();
            final View dialogView = inflater.inflate(R.layout.view_order_dialog,null);
            dialogBuilder.setView(dialogView);
            final TextView orderTextView = dialogView.findViewById(R.id.orderTextView);
            final Button close = dialogView.findViewById(R.id.close);
            orderTextView.setText(order);
            dialogBuilder.setTitle("Order ID: " + orderID.getText().toString());
            final AlertDialog alertDialog = dialogBuilder.create();
            alertDialog.show();
        }
    });
    cardView.addView(relativeLayout);
    relativeLayout.addView(textView);
    relativeLayout.addView(orderID);
    relativeLayout.addView(viewOrder);
    relativeLayout.addView(orderDate);
    gridLayout.addView(cardView);
}

我无法从片段启动自定义对话框视图。当我打开该片段时，它会使应用程序崩溃。我正在使用此代码动态创建卡片并为每张卡片创建一个 OnClickListner。

Answer 1

您的活动 context 在此行中为空：

AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(getActivity()); // getActivity() is getting null here

为避免崩溃，您应该包装您的代码并检查您的活动上下文是否不为空，如下所示：

if(getActivity() != null){
   AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(getActivity());
   LayoutInflater inflater = getLayoutInflater();
   final View dialogView = inflater.inflate(R.layout.view_order_dialog,null);
   dialogBuilder.setView(dialogView);
   final TextView orderTextView = dialogView.findViewById(R.id.orderTextView);
   orderTextView.setText(order);
   final AlertDialog alertDialog = dialogBuilder.create();
   alertDialog.show();
}

Answer 2

在我的情况下，如果在 RecyclerView 项目单击上显示对话框，则会显示这种类型的错误。

1) 像这样在你的类中定义 Activity：-

       // Initialize activity
       Activity activity;

      // define activity of this class//
        activity=EditFieldsActivity.this;

2）像这样在您的适配器中传递此活动：-

EditFieldAdapter adapter = new EditFieldAdapter(getApplicationContext(),data,activity);
recyclerFieldManagement.setAdapter(adapter);

3）并在您的适配器中获取此活动并使用活动将对话框显示为：-

private Activity activity;
    public EditFieldAdapter(Context applicationContext, List<FieldDetails> data, Activity activity) {
        this.ctx=applicationContext;
        this.data=data;
        this.activity=activity;
    }

希望这会对您有所帮助。谢谢...

Answer 3

如果您使用YourActivityName.this 而不是context，您的问题将得到解决。 例如;

final AlertDialog.Builder alertDialog = new AlertDialog.Builder(MainActivity.this);
                alertDialog.setTitle("Take a Note ");

                                   or

final EditText edtText = new EditText(MainActivity.this);
                edtText.setText("editText");
                parent.addView(edtText);