[英]Attempt to invoke virtual method 'void android.widget.RadioGroup.addView(android.view.View)' on a null object reference
I am a beginner in android and i using java language not Kotlin.我是 android 的初学者,我使用的是 java 语言而不是 Kotlin。 Basically i am showing a custom alert dialog after button press, inside an alert dialog there is two radio buttons.
基本上我在按钮按下后显示一个自定义警报对话框,在警报对话框中有两个单选按钮。 But problem is after clicking a button in order to show the custom dialog it gets crashed showing null point exception.
但问题是在单击按钮以显示自定义对话框后,它会崩溃并显示空点异常。 Below is the code and log.
下面是代码和日志。
CustomDialog.java
自定义对话框
public class CustomDialog extends AppCompatDialogFragment {
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
AlertDialog.Builder builder=new AlertDialog.Builder(getActivity());
LayoutInflater layoutInflater=getActivity().getLayoutInflater();
View view=layoutInflater.inflate(R.layout.custom_dialog,null);
builder.setView(view)
.setTitle("Check Methods");
final int[] num=getResources().getIntArray(R.array.methods);
RadioButton radioButton=new RadioButton(getActivity());
RadioButton radioButton1=new RadioButton(getActivity());
radioButton.setText("A");
RadioGroup radioGroup=getActivity().findViewById(R.id.radioGroup);
radioButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int kk=num[0];
int aa=kk;
}
});
radioButton1.setText("B");
radioGroup.addView(radioButton); //In this line it is showing null point exception and in debugging it is showing "radioGroup" is null
radioGroup.addView(radioButton1);
return builder.create();
}
}
custom_dialog.xml
custom_dialog.xml
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RadioGroup
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/radioGroup"/>
</LinearLayout>
methods.xml
方法文件
<resources>
<integer-array name="methods">
<item>0</item>
</integer-array>
</resources>
MainActivity.Java
主Activity.Java
btnMethod.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
openDialog(); //to show custom dialog after button press
}}
private void openDialog() {
CustomDialog customDialog=new CustomDialog();
customDialog.show(getSupportFragmentManager(),"Custom Dialog");
}
Logs
日志
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.RadioGroup.addView(android.view.View)' on a null object reference at com.nabil.myapplication.CustomDialog.onCreateDialog(CustomDialog.java:33) at android.support.v4.app.DialogFragment.onGetLayoutInflater(DialogFragment.java:330) at android.support.v4.app.Fragment.performGetLayoutInflater(Fragment.java:1308) at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1460) at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1784) at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1852) at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:802) at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2625) at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2411) at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecu java.lang.NullPointerException:尝试在 com.nabil.myapplication.CustomDialog.onCreateDialog(CustomDialog.java:33) 的空对象引用上调用虚拟方法“void android.widget.RadioGroup.addView(android.view.View)”在 android.support.v4.app.DialogFragment.onGetLayoutInflater(DialogFragment.java:330) 在 android.support.v4.app.Fragment.performGetLayoutInflater(Fragment.java:1308) 在 android.support.v4.app.FragmentManagerImpl.moveToState (FragmentManager.java:1460) at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1784) at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1852) at android.support. v4.app.BackStackRecord.executeOps(BackStackRecord.java:802) at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2625) at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:第2411章) te(FragmentManager.java:2366) at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273) at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:733) at android.os.Handler.handleCallback(Handler.java:907) at android.os.Handler.dispatchMessage(Handler.java:105) at android.os.Looper.loop(Looper.java:216) at android.app.ActivityThread.main(ActivityThread.java:7625) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:987)
te(FragmentManager.java:2366) at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273) at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:733) at android。 os.Handler.handleCallback(Handler.java:907) at android.os.Handler.dispatchMessage(Handler.java:105) at android.os.Looper.loop(Looper.java:216) at android.app.ActivityThread.main (ActivityThread.java:7625) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524) at com.android.internal.os .ZygoteInit.main(ZygoteInit.java:987)
Because RadioGroup
is an element of the custom_dialog.xml
then you must find RadioGroup
from View of custom_dialog.xml
, try with the code:因为
RadioGroup
是custom_dialog.xml
一个元素,所以你必须从custom_dialog.xml
View 中找到RadioGroup
,尝试使用代码:
LayoutInflater layoutInflater=getActivity().getLayoutInflater();
View view=layoutInflater.inflate(R.layout.custom_dialog,null); //load custom_dialog.xml to View
...
RadioGroup radioGroup=view.findViewById(R.id.radioGroup); //try to retrieve rarioGroup in custom_dialog.xml
Change this line:改变这一行:
RadioGroup radioGroup=getActivity().findViewById(R.id.radioGroup);
to:到:
RadioGroup radioGroup = view.findViewById(R.id.radioGroup);
radioGroup
is in your dialog radioGroup
在您的对话中
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.