我使用单选按钮时出现空指针异常

Question

我想在RadioButton框架中使用dialog和RadioButton框架中的所有内容，但当我想从NullPointerException获取文字时，我会得到LayoutInflater layoutInflater = LayoutInflater.from(context); View promptView = layoutInflater.inflate(R.layout.prompt_permission, null); final RadioGroup radioSexGroup = (RadioGroup) promptView.findViewById(R.id.droit); AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context); // set prompts.xml to be the layout file of the alertdialog builder alertDialogBuilder.setView(promptView); final EditText input = (EditText) promptView.findViewById(R.id.editTextMailUserInput); // setup a dialog window alertDialogBuilder .setCancelable(false) .setPositiveButton("OK", new android.content.DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { //input.setText(input.getText()); int selectedId = radioSexGroup.getCheckedRadioButtonId(); RadioButton radioSexButton =(RadioButton) findViewById(selectedId); System.out.println(radioSexButton.getText()); } }) .setNegativeButton("Cancel", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { dialog.cancel(); } }); // create an alert dialog AlertDialog alertD = alertDialogBuilder.create(); alertD.show();` 。

我的布局xml文件：

06-08 16:10:14.420: E/AndroidRuntime(3645): FATAL EXCEPTION: main
06-08 16:10:14.420: E/AndroidRuntime(3645): java.lang.NullPointerException
06-08 16:10:14.420: E/AndroidRuntime(3645):     at com.example.poc_cubbyhole.MainActivity$4.onClick(MainActivity.java:190)
06-08 16:10:14.420: E/AndroidRuntime(3645):     at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:159)
06-08 16:10:14.420: E/AndroidRuntime(3645):     at android.os.Handler.dispatchMessage(Handler.java:99)
06-08 16:10:14.420: E/AndroidRuntime(3645):     at android.os.Looper.loop(Looper.java:123)
06-08 16:10:14.420: E/AndroidRuntime(3645):     at android.app.ActivityThread.main(ActivityThread.java:3683)
06-08 16:10:14.420: E/AndroidRuntime(3645):     at java.lang.reflect.Method.invokeNative(Native Method)
06-08 16:10:14.420: E/AndroidRuntime(3645):     at java.lang.reflect.Method.invoke(Method.java:507)
06-08 16:10:14.420: E/AndroidRuntime(3645):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
06-08 16:10:14.420: E/AndroidRuntime(3645):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
06-08 16:10:14.420: E/AndroidRuntime(3645):     at dalvik.system.NativeStart.main(Native Method)

这是我的logCat错误：

{{1}}

Answer 1

你应该这样做：

public void onClick(DialogInterface dialog, int id) {                                   
    //input.setText(input.getText());

    int selectedId = radioSexGroup.getCheckedRadioButtonId();

   // change this part like this
     RadioButton radioSexButton =(RadioButton) promptView.findViewById(selectedId);

    System.out.println(radioSexButton.getText());  
}