HomeActivity 必须实现 AlertPositiveListener

Question

由于我在 android 中比较新鲜，所以请帮帮我。单击 Imagebutton 时，将显示带有单选按钮的警报对话框窗口。下面是我用来获取警报对话框的代码。

PhotosAdapter.java：

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

                    FragmentManager manager = ((Activity) mCtx).getFragmentManager();

                    AlertDialogRadio alert = new AlertDialogRadio();                         
                    Bundle b  = new Bundle();                            
                    b.putInt("position", position);                          
                    alert.setArguments(b);    
                    alert.show(manager, "alert_dialog_radio");
                }
            });

AlertDialogRadio.java：

public class AlertDialogRadio extends DialogFragment {


    AlertPositiveListener alertPositiveListener;            
    public interface AlertPositiveListener {
        public void onPositiveClick(int position);
    }

    public void setListener(AlertPositiveListener alertPositiveListener){
        this.alertPositiveListener=alertPositiveListener;
    }

    public void onAttach(android.app.Activity activity) {
        super.onAttach(activity);
        try{
            alertPositiveListener = (AlertPositiveListener) activity;
        }catch(ClassCastException e){

            throw new ClassCastException(activity.toString() + " must implement AlertPositiveListener");
        }
    }


    OnClickListener positiveListener = new OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            AlertDialog alert = (AlertDialog)dialog;
            int position = alert.getListView().getCheckedItemPosition();
            alertPositiveListener.onPositiveClick(position);
        }
    };


    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {


        Bundle bundle = getArguments();
        int position = bundle.getInt("position");


        AlertDialog.Builder b = new AlertDialog.Builder(getActivity());              
        b.setTitle("Choose your version");          
        b.setSingleChoiceItems(RadioButtonList.Android.code, position, null);

        b.setPositiveButton("OK",positiveListener);                
        b.setNegativeButton("Cancel", null);            
        AlertDialog d = b.create();               
        return d;
    }
}

Android.java：

public class Android {
    static String[] code = new String[]{
            "Not Intrested",
            "Sexual Content",
            "Violent or repulsive content",
            "Spam or misleading",
            "Infringes my rights",
            "Wrong description",
            "Description is not complete"
    };
}

不幸的是，当单击 Imagebutton 时，应用程序崩溃了。

LogCatError：

E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.splash.indivillage.indishare, PID: 10084
                  java.lang.ClassCastException: com.splash.indivillage.indishare.Home.HomeActivity@e7e35e6 must implement AlertPositiveListener
                      at com.splash.indivillage.indishare.Utils.AlertDialogRadio.onAttach(AlertDialogRadio.java:37)
                      at android.app.Fragment.onAttach(Fragment.java:1454)
                      at android.app.DialogFragment.onAttach(DialogFragment.java:365)
                      at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:937)
                      at android.app.BackStackRecord.setLastIn(BackStackRecord.java:860)
                      at android.app.BackStackRecord.calculateFragments(BackStackRecord.java:883)
                      at android.app.BackStackRecord.run(BackStackRecord.java:728)
                      at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1580)
                      at android.app.FragmentManagerImpl$1.run(FragmentManager.java:483)
                      at android.os.Handler.handleCallback(Handler.java:754)
                      at android.os.Handler.dispatchMessage(Handler.java:95)
                      at android.os.Looper.loop(Looper.java:163)
                      at android.app.ActivityThread.main(ActivityThread.java:6205)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)

已编辑：enter image description here

请帮帮我。谢谢你。

Answer 1

如错误提示，您必须在使用 AlertDialog 的 HomeActivity 中实现 AlertPositiveListener

HomeActivity implements AlertPositiveListener

然后你必须覆盖在你的 home Activity 的接口中声明的方法。

@Override
public void onPositiveClick(int position){
// implement your code here
}

查看this 了解界面的工作原理。

Answer 2

您收到错误是因为您必须在您的 fragment.interface 方法中覆盖接口方法onPositiveClick(int position)

 HomeActivity implements AlertDialogListener{

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup 
    container, @Nullable Bundle savedInstanceState) {

         AlertDialogRadio alert = new AlertDialogRadio();
         alert.setListener(this)
        }

        @Override
        public void onPositiveClick(int position){
         //this method you have to override
        }   
      }

希望对你有帮助！！

Answer 3

您正在将 Activity 的上下文转换为 Interface 引用变量，并且 Parent Activity 和 AlertPositiveListener 之间没有关系。

解决方案可以是多个。不要在 Activity 中使用 Casting 工具 AlertPositiveListener。

HomeActivity implements AlertDialogListener{
@Override
public void onPositiveClick(int position){
// Do your stuff
  }
 }

并在交易前设置如下监听器。

AlertDialogRadio alert = new AlertDialogRadio();
 alert.setListener(this)
Bundle b = new Bundle();
b.putInt("position",position);
alert.setArguments(b);
alert.show(manager,"alert_dialog_radio");

然后只需使用alertPositiveListener 进行回调，无需强制转换。