android - Attempt to invoke virtual method on Attempt to invoke virtual method android.widget.EditText.getText() 对空对象引用

Question

尝试从对话框中的 EditText 获取 Edit Text 的值，但一次又一次地出现此错误

Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference

我正在通过另一个对话框膨胀 View 它工作正常但是每当我在对话框中单击“确定”时我总是收到上述错误

LayoutInflater li = LayoutInflater.from(getContext());
                View promptsView = li.inflate(R.layout.custom_dimension_dialog, null);
                AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
                        getContext());
                // set prompts.xml to alertdialog builder
                alertDialogBuilder.setView(promptsView);
                alertDialogBuilder
                        .setCancelable(false)
                        .setPositiveButton("OK",
                                new OnClickListener() {
                                    public void onClick(DialogInterface dialog, int id) {
                                        // get user input and set it to result
                                        // edit text
                                        widthEditText = findViewById(R.id.Width);
                                        heightEditText = findViewById(R.id.Height);
                                        String width = widthEditText.getText().toString();
                                        String height = heightEditText.getText().toString();
                                        Toast.makeText(mContext, "Values are: " + width + " " + height, Toast.LENGTH_SHORT).show();
//                                        WIDTH=width
//                                        HEIGHT=height;
                                    }
                                })
                        .setNegativeButton("Cancel",
                                new OnClickListener() {
                                    public void onClick(DialogInterface dialog, int id) {
                                        dialog.cancel();
                                    }
                                }).show(); 

Answer 1

您没有为 edittext 提供任何 View 以这种方式更改您的代码

 widthEditText = promptsView.findViewById(R.id.Width);                                 
 heightEditText = promptsView.findViewById(R.id.Height);