Question

应用程序崩溃，当我点击服务器RPC时，当RPC正在进行时，我将应用程序放在后台。同时，当RPC从服务器获取响应时，它会从堆栈中弹出一个片段。弹出片段时，应用程序崩溃。我已经阅读了有关创建WeakReference的内容，如果活动被销毁，它将为null。但不确定如何实现这种情况。

以下是我的代码：

private void showFragment(SherlockFragment fragment) {
    FragmentManager fm = getSupportFragmentManager();
    fm.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
    FragmentTransaction ft = fm.beginTransaction();
    ft.replace(R.id.content, fragment);
    ft.commit();
}

我在执行以下行时遇到了崩溃：

fm.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);

StackTrace：

01-15 16:37:44.435: E/AndroidRuntime(28049): FATAL EXCEPTION: main
01-15 16:37:44.435: E/AndroidRuntime(28049): java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
01-15 16:37:44.435: E/AndroidRuntime(28049):    at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1299)
01-15 16:37:44.435: E/AndroidRuntime(28049):    at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1310)
01-15 16:37:44.435: E/AndroidRuntime(28049):    at android.support.v4.app.FragmentManagerImpl.popBackStack(FragmentManager.java:452)
01-15 16:37:44.435: E/AndroidRuntime(28049):    at com.druva.inSync.ValidationActivity$2.run(ValidationActivity.java:93)

Answer 1

我遇到了完全相同的问题，我使用旗帜解决了这个问题。它可能看起来有点＆＃34; hacky＆＃34;但是它完成了工作

public abstract class PopActivity extends Activity {

    private boolean mVisible; 

   @Override
    public void onResume() {
        super.onResume();
        mVisible = true;
    }

    @Override
    protected void onPause() {
        super.onPause();
        mVisible = false;
    }

    private void popFragment() {
        if (!mVisible) {
            return;
        }

        FragmentManager fm = getSupportFragmentManager();
        fm.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
    }
}

因此，当您在恢复应用程序时单独实现上述代码时，您会发现自己处于一个实际上想要弹出的片段中。您可以使用以下剪辑来解决此问题：

public abstract class PopFragment extends Fragment {

    private static final String KEY_IS_POPPED = "KEY_IS_POPPED";
    private boolean mPopped;

    @Override
    public void onSaveInstanceState(Bundle outState) {
        outState.putBoolean(KEY_IS_POPPED, mPopped);
        super.onSaveInstanceState(outState);
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (savedInstanceState != null) {
            mPopped = savedInstanceState.getBoolean(KEY_IS_POPPED);
        }
    }

    @Override
    public void onResume() {
        super.onResume();
        if (mPopped) {
            popFragment();
        }
    }

    protected void popFragment() {
        mPopped = true;
        // null check and interface check advised
        ((PopActivity) getActivity()).popFragment();
    }
}

当从堆栈弹出片段时，应用程序在后台崩溃

1 个答案: