java - Android:IllegalStateException: Activity 已被销毁

Question

我在 stackoverflow 上看到了很多类似的问题，但我不知道我做错了什么。我制作了一个非常简单的应用程序来复制错误。

该应用程序执行以下操作:
它在 MainActivty 的 onCreate 中添加一个 fragment 。
用户可以从对话框中添加另一个 fragment 。
当对话框调用 MainActivity 的 addFragment 方法时，会在提交事务时引发异常。

这是主要 Activity

package com.example.testapp;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTransaction;
import android.view.View;
import android.widget.Button;

public class MainActivity extends FragmentActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final Button button = (Button) findViewById(R.id.add_button);
    button.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
             AddButtonDialog addButtonDialog = new AddButtonDialog();
             addButtonDialog.show(getSupportFragmentManager(), "ADD");
        }
    });

    FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
    CustomFragment fragment = new CustomFragment();
    transaction.add(R.id.fragment_container, fragment);
    transaction.commit();
}


public void addButton() {
    FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
    CustomFragment fragment = new CustomFragment();
    transaction.add(R.id.fragment_container, fragment);
    transaction.commit(); // <-- Exception

}

}

这是调用 MainActivity 的 AddButtonDialog

 public class AddButtonDialog  extends DialogFragment {
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        final AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        final LayoutInflater inflater = getActivity().getLayoutInflater();
        View view = inflater.inflate(R.layout.new_button_dialog, null);
        builder.setView(view)

               .setPositiveButton("Add", new DialogInterface.OnClickListener() {
                   @Override
                   public void onClick(DialogInterface dialog, int id) {
                       MainActivity main = new MainActivity();
                       main.addButton();
                   }
               });
        return builder.create();   
    }
}

这是堆栈跟踪

    02-14 10:09:27.781: E/AndroidRuntime(26291): FATAL EXCEPTION: main
    02-14 10:09:27.781: E/AndroidRuntime(26291): java.lang.IllegalStateException: Activity has been destroyed
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1365)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:595)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at android.support.v4.app.BackStackRecord.commit(BackStackRecord.java:574)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at com.example.testapp.MainActivity.addButton(MainActivity.java:35)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at com.example.testapp.AddButtonDialog$1.onClick(AddButtonDialog.java:22)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:185)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at android.os.Handler.dispatchMessage(Handler.java:99)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at android.os.Looper.loop(Looper.java:137)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at android.app.ActivityThread.main(ActivityThread.java:5328)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at java.lang.reflect.Method.invokeNative(Native Method)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at java.lang.reflect.Method.invoke(Method.java:511)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
    02-14 10:09:27.781: E/AndroidRuntime(26291):    at dalvik.system.NativeStart.main(Native Method)

我相当确定我没有掌握 Fragment 生命周期的概念。请有人好心地解释一下我做错了什么。

Answer 1

将 MainActivity 的引用传递给对话框并尝试此操作

mainActivity.addButton()

其中 mainActivity 是引用