片段必须是要从实例状态正确重新创建的公共静态类

Question

更新到最新的支持存储库后,

compile 'com.android.support:appcompat-v7:24.2.0'
compile 'com.android.support:design:24.2.0'
compile 'com.android.support:percent:24.2.0'
compile 'com.android.support:recyclerview-v7:24.2.0'

我得到了奇怪的例外.

java.lang.IllegalStateException: Fragment null must be a public static class to be  properly recreated from instance state.
at android.support.v4.app.BackStackRecord.doAddOp(BackStackRecord.java:435)
at android.support.v4.app.BackStackRecord.add(BackStackRecord.java:414)
at android.support.v4.app.DialogFragment.show(DialogFragment.java:154)
at com.androidapp.base.BaseActivity.showDialogFragment(BaseActivity.java:78)
at com.androidapp.MainActivity.showNewDialog(MainActivity.java:304)
at com.androidapp.MainActivity$6.onClick(MainActivity.java:228)

在我的BaseActivity类中,我创建了一个可重用的片段,可以在扩展BaseActivty的 activity类中使用

public void showDialogFragment(DialogFragment newFragment) {
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        Fragment prev = getSupportFragmentManager().findFragmentByTag("dialog");
        if (prev != null) {
            ft.remove(prev);
        }
        ft.addToBackStack("dialog");
        newFragment.show(ft, "dialog");
    }

回到MainActivty我用过像这样的片段,

public class MainActivity extends BaseActivity {

    @SuppressLint("ValidFragment")
        public void showNewDialog(int type, String title, String message) {
            final DialogNew dialog = new DialogNew() {
                @Override
                public void success(boolean isLandscape) {
                    .......
                }

                @Override
                public void cancel() {

                }
            };
            dialog.setArgs(title, message);
            super.showDialogFragment(dialog);
        }
}

该DialogNew类如下,

public abstract class DialogNew extends DialogFragment {

    private View rootView;

    private String title;
    private String message;

    public void setArgs(String title, String message) {
        Bundle args = new Bundle();
        args.putString("title", title);
        args.putString("message", message);
        setArguments(args);
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setStyle(STYLE_NO_TITLE, 0);
    }

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

        rootView = inflater.inflate(R.layout.fragment_new_dialog, container, false);

        init();
        setListeners();

        return rootView;
    }

    public abstract void success(boolean isLandscape);

    public abstract void cancel();
}

PS:相同的代码适用于较旧的支持存储库.

Answer 1

这个错误并不特别奇怪.如果您之前没有收到此错误,那很奇怪.

Android会破坏并重新创建片段作为配置更改的一部分(例如,屏幕旋转),并在需要时重建任务的一部分(例如,用户切换到另一个应用程序,您的应用程序的进程在后台终止,然后用户终止尝试返回您的应用程序,所有都在30分钟左右).Android无法重新创建匿名子类DialogNew.

因此,创建一个扩展并具有业务逻辑的常规publicJava类(或public static嵌套类)DialogNew,替换DialogNew当前使用的匿名子类.