带有EditText的Android对话框引发NullPointerException

我试图弹出一个对话框，显示有关ListView中条目的更多信息。ListView生成良好，对话框的所有变量初始化良好，但当我尝试将相关描述写入EditText框时，会引发NullPointerException。有什么想法吗

@Override
  protected void onListItemClick(ListView l, View v, int position, long id) {
    //TODO Add code for action performed on item click here
    // i.e. open dialogue showing details

    // Custom dialog box
    final Dialog dialog = new Dialog(context);
    dialog.setContentView(R.layout.view_dialog);
    dialog.setTitle("Description: " + savedSubjects[position]);

    // set custom dialog components
    EditText descriptionOutput = (EditText) findViewById(R.id.dialogText);
    String descToWrite = savedDescriptions[position]; // I created this in case calling from the array was the problem. In the trace this variable is correctly set.

    descriptionOutput.setText(descToWrite); //the error occurs at this line


    // set dismiss button
    Button dialogButton = (Button) findViewById(R.id.dialogButton);
    //if button is clicked close the dialog
    dialogButton.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
            dialog.dismiss();
        }
    });

    // display the dialog
    dialog.show();
  }

使用

而不是

EditText descriptionOutput = (EditText) findViewById(R.id.dialogText);

要从对话框布局访问编辑文本，请使用

而不是

EditText descriptionOutput = (EditText) findViewById(R.id.dialogText);

从对话框布局访问编辑文本的步骤