Android 使用按钮切换片段（带NavigationDrawer）

我有一个

NavigationDrawer

，我用它在

Fragment

s之间切换。我想做的是在我的一个片段中有一个按钮，它充当

NavigationDrawer

中另一个

Fragment

的“快捷方式”

在

NavigationDrawer

中，我切换如下片段：

private class DrawerItemClickListener implements
            ListView.OnItemClickListener {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position,
                long id) {

            selectItem(position);
        }
    }

public void selectItem(int position) { 

        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        String fragmentTag = String.valueOf(position);

        FragmentBase fragment = (FragmentBase) fragmentManager
                .findFragmentByTag(fragmentTag);
        if (null == fragment) { 
            fragment = createFragmentByPosition(position);
        }
        if (null == fragment)
            return;

        if (fragment.isAdded()) {
            fragmentTransaction.show(fragment);
        } else {
            fragmentTransaction.replace(R.id.content_frame, fragment, fragmentTag); 
        }

        if (mCurrentFragment != null) {
            fragmentTransaction.hide(mCurrentFragment);
        }
        mCurrentFragment = fragment;
        fragmentTransaction.commitAllowingStateLoss();

        mDrawerList.setItemChecked(position, true);
        setTitle(mNoterActivities[position]);
        mDrawerLayout.closeDrawer(mDrawerList);
    }

    private FragmentBase createFragmentByPosition(int position) { // FragmentBase just extends Fragment
        FragmentBase fragment = null;

        if (position == 0) {
            fragment = new Fragment1();
            Bundle args = new Bundle();
            fragment.setArguments(args);

        } else if (position == 1) { // Reminder
            fragment = new Fragment2();
            Bundle args = new Bundle();
            fragment.setArguments(args);

        }

        return fragment;
    }

在片段B（位置1）中：

---

这似乎太简单了，难怪它不起作用

首先，在

上选择item

方法，使用

add

方法代替

replace

方法：

public void selectItem(int position) {

    FragmentManager fragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    String fragmentTag = String.valueOf(position);

    FragmentBase fragment = (FragmentBase) fragmentManager.findFragmentByTag(fragmentTag);
    if (null == fragment) {
        fragment = createFragmentByPosition(position);
    }
    if (null == fragment)
        return;

    if (fragment.isAdded()) {
        fragmentTransaction.show(fragment);
    } else {
        // fragmentTransaction.replace(R.id.content_frame, fragment, fragmentTag); 
        fragmentTransaction.add(R.id.content_frame, fragment, fragmentTag);
    }

    if (mCurrentFragment != null) {
        fragmentTransaction.hide(mCurrentFragment);
    }
    mCurrentFragment = fragment;
    fragmentTransaction.commitAllowingStateLoss();

    mDrawerList.setItemChecked(position, true);
    setTitle(mNoterActivities[position]);
    mDrawerLayout.closeDrawer(mDrawerList);
}

其次，

Navigation\u Drawer

中的

getInstance

方法不应创建新的

Navigation\u Drawer

当

instance

为空时，在

导航\u Drawer

中创建

this

中设置instance，然后在调用

getInstance

时返回

instance

：

private static Navigation_Drawer mInstance;

public static Navigation_Drawer getInstance() {
    return mInstance;
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    mInstance = this;
    // other codes here:
}

QuickNoteFragment

的id为0，而

PendViewPager

的id为1。您可以在

QuickNoteFragment

中转到

PendViewPager

：

Navigation_Drawer.getInstance().selectItem(1);

-

更新1：如何将数据传递到片段：

QuickNoteFragment

和

HistoryFragment

具有相同的父类：

FragmentBase

，我们添加了一个名为

onDataIn

的方法来接收数据：

public class FragmentBase extends Fragment {

    public void function onDataIn(Object data) {
    }
}

public void selectItem(int position, Object data) {

    FragmentManager fragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    String fragmentTag = String.valueOf(position);

    FragmentBase fragment = (FragmentBase) fragmentManager.findFragmentByTag(fragmentTag);
    if (null == fragment) {
        fragment = createFragmentByPosition(position);
    }
    if (null == fragment)
        return;

    // call onDataIn() method.
    fragment.onDataIn(data);

    if (fragment.isAdded()) {
        fragmentTransaction.show(fragment);
    } else {
        // fragmentTransaction.replace(R.id.content_frame, fragment, fragmentTag); 
        fragmentTransaction.add(R.id.content_frame, fragment, fragmentTag);
    }

    if (mCurrentFragment != null) {
        fragmentTransaction.hide(mCurrentFragment);
    }
    mCurrentFragment = fragment;
    fragmentTransaction.commitAllowingStateLoss();

    mDrawerList.setItemChecked(position, true);
    setTitle(mNoterActivities[position]);
    mDrawerLayout.closeDrawer(mDrawerList);
}

我们应该更改

selectItem

，添加参数以接收数据：

public class FragmentBase extends Fragment {

    public void function onDataIn(Object data) {
    }
}

public void selectItem(int position, Object data) {

    FragmentManager fragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    String fragmentTag = String.valueOf(position);

    FragmentBase fragment = (FragmentBase) fragmentManager.findFragmentByTag(fragmentTag);
    if (null == fragment) {
        fragment = createFragmentByPosition(position);
    }
    if (null == fragment)
        return;

    // call onDataIn() method.
    fragment.onDataIn(data);

    if (fragment.isAdded()) {
        fragmentTransaction.show(fragment);
    } else {
        // fragmentTransaction.replace(R.id.content_frame, fragment, fragmentTag); 
        fragmentTransaction.add(R.id.content_frame, fragment, fragmentTag);
    }

    if (mCurrentFragment != null) {
        fragmentTransaction.hide(mCurrentFragment);
    }
    mCurrentFragment = fragment;
    fragmentTransaction.commitAllowingStateLoss();

    mDrawerList.setItemChecked(position, true);
    setTitle(mNoterActivities[position]);
    mDrawerLayout.closeDrawer(mDrawerList);
}

为了使

selectItem

兼容，我们应该添加一个重载的

selectItem

方法

public void selectItem(int postion) {
    selectItem(position, null);
}

---

这样，我们就不需要更改调用

selectItem

的旧代码，也不需要将数据传递给fragement。

谢谢。我还有一个小问题——如果我在按下按钮时使用它，我会用按钮将数据从片段传递到我想要的片段。在start（）和on resume（）上都没有调用，所以我无法接收意图。也许ifVisibleToUser会起作用。我会尝试的。我给出了一些关于将数据传递到片段的代码，希望它会有所帮助。谢谢-我已经运行了它，但是我不知道当我在另一个片段中时如何检索数据。我添加了

Navigation\u Drawer.getInstance（）.selectItem（0，“mytext”）

在HistoryFragments中，您可以覆盖

onDataIn

方法来处理要在其中检索数据的片段中的数据。