Question

我希望在手机未连接到WiFi网络时显示另一个片段。通常我正在显示MainFragment，当没有连接可用时ErrorFragment。

我正在使用mWifi.isConnected()检查是否存在连接。

@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    if (mWifi.isConnected()) {
        new PostTask(1).execute();
    } else {
        MainFragment.firstPageListener.onSwitchToNextFragment();
    }
}

这是我的代码（在MainFragment中）切换到ErrorFragment，但它给了我

11-23 20:57:29.588: E/AndroidRuntime(4025): java.lang.IllegalStateException: Recursive entry to executePendingTransactions

这是我的MainActivity（我正在使用ViewPager）：

public class SectionsPagerAdapter extends FragmentPagerAdapter {

    private final class FirstPageListener implements FirstPageFragmentListener {
        public void onSwitchToNextFragment() {
            mFragmentManager.beginTransaction().remove(mFragmentAtPos0).commit();
            if (mFragmentAtPos0 instanceof MainFragment) {
                mFragmentAtPos0 = new ErrorFragment(listener);
            } else { // Instance of NextFragment
                mFragmentAtPos0 = new MainFragment(listener);
            }
            notifyDataSetChanged();
        }
    }

    private String[] titles = { "SEARCH", "LIST" };
    private final FragmentManager mFragmentManager;
    public Fragment mFragmentAtPos0;
    private Context context;
    FirstPageListener listener = new FirstPageListener();

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
        mFragmentManager = fm;
    }

    @Override
    public Fragment getItem(int position) {
        switch (position) {
        case 0: // Fragment # 0
            if (mFragmentAtPos0 == null) {
                mFragmentAtPos0 = new MainFragment(listener);
            }
            return mFragmentAtPos0;

        case 1: // Fragment # 1
            return new ListFragment();
        }
        return null;
    }

    @Override
    public int getCount() {
        return titles.length;
    }

    @Override
    public int getItemPosition(Object object) {
        if (object instanceof MainFragment && mFragmentAtPos0 instanceof ErrorFragment) {
            return POSITION_NONE;
        }
        if (object instanceof MainFragment && mFragmentAtPos0 instanceof MainFragment) {
            return POSITION_NONE;
        }
        return POSITION_UNCHANGED;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return titles[position];
    }
}

public interface MainFragmentListener {
    void onSwitchToNextFragment();
}

我尝试用以下内容更改片段：

FragmentManager fragmentManager2 = getFragmentManager();
FragmentTransaction fragmentTransaction2 = fragmentManager2.beginTransaction();
ErrorFragment fragment2 = new ErrorFragment();
fragmentTransaction2.addToBackStack("xyz");
fragmentTransaction2.hide(MainFragment.this);
fragmentTransaction2.add(android.R.id.content, fragment2);
fragmentTransaction2.commit();

但是当我滑到另一个标签时，片段重叠......应该怎么做？谢谢！

（拇指向下是ErrorFragment，按钮和开/关开关，在ListFragment中）

enter image description here

Answer 1

尝试删除 fragmentTransaction2.hide（MainFragment.this）; 并改变 fragmentTransaction2.add（android.R.id.content，fragment2）; 至 fragmentTransaction2.replace（android.R.id.content，fragment2）;

尝试替换Fragment时出现IllegalStateException

1 个答案: