如何在 AlertDialog 中读取 RadioGroup 的值？

Question

所以我正在使用 AlertDialog 来显示我的 RadioGroup，我想获取 RadioButton 的值以传递给我的下一个方法。然而，当我运行程序时它 returns 一个错误：

java.lang.NullPointerException: Attempt to invoke virtual method 'int android.widget.RadioGroup.getCheckedRadioButtonId()' on a null object reference

我该如何解决这个问题？

private void showChoosePackage() {

    AlertDialog.Builder builder = new AlertDialog.Builder(descriptionsActivity.this);
    LayoutInflater inflater = this.getLayoutInflater();
    View choose_package_layout = inflater.inflate(R.layout.choose_package_layout, null);

    builder.setView(choose_package_layout);
    final  AlertDialog dialog = builder.create();

    radioGroup = findViewById(R.id.radio_grp);
    Button btnApply = choose_package_layout.findViewById(R.id.button_apply);

    final RadioButton rdibtn = (RadioButton)choose_package_layout.findViewById(R.id.radio1);
    final RadioButton rdibtn2 = (RadioButton)choose_package_layout.findViewById(R.id.radio2);

    rdibtn.setText(Common.longhousedesc.PackageOne);
    rdibtn2.setText(Common.longhousedesc.PackageTwo);

    btnApply.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            int Selectedid = radioGroup.getCheckedRadioButtonId();
            radioButton = findViewById(Selectedid);

            showConfirmDialog(radioButton.getText());
        }
    });

    builder.show();

}

Answer 1

查找单选组时需要指定视图：

radioGroup = choose_package_layout.findViewById(R.id.radio_grp);

Answer 2

findViewById 需要上下文才能找到视图。由于您是在对话框中调用它，因此您需要在其视图中找到该视图。

private void showChoosePackage() {

    AlertDialog.Builder builder = new AlertDialog.Builder(descriptionsActivity.this);
    LayoutInflater inflater = this.getLayoutInflater();
    final View choose_package_layout = inflater.inflate(R.layout.choose_package_layout, null);

    builder.setView(choose_package_layout);
    final  AlertDialog dialog = builder.create();

    final RadioGroup radioGroup = findViewById(R.id.radio_grp);
    Button btnApply = choose_package_layout.findViewById(R.id.button_apply);

    final RadioButton rdibtn = (RadioButton)choose_package_layout.findViewById(R.id.radio1);
    final RadioButton rdibtn2 = (RadioButton)choose_package_layout.findViewById(R.id.radio2);

    rdibtn.setText(Common.longhousedesc.PackageOne);
    rdibtn2.setText(Common.longhousedesc.PackageTwo);

    btnApply.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            int Selectedid = radioGroup.getCheckedRadioButtonId();
            radioButton = choose_package_layout.findViewById(Selectedid);

            showConfirmDialog(radioButton.getText());
        }
    });



    dialog.show();

     }

如何在 AlertDialog 中读取 RadioGroup 的值？

How do I read the value of my RadioGroup in an AlertDialog?

android

android-alertdialog

android-radiogroup