从android中的片段管理工具栏的导航和后退按钮

Question

我的所有片段都是通过ActionBarActivity（mainActivity）控制的，在mainActivity中实现了一个抽屉布局，所有子片段都是通过抽屉布局的列表项点击来推送的。我面临的问题是，在通过抽屉布局推送片段后，我想将抽屉图标更改为工具栏的后图标，以便用户可以导航到前一个片段并处理Android的回调。R、 id.home位于同一片段内或主活动内。

我使用的代码是：

MainActivity.java

public class MainActivity extends ActionBarActivity {
    private DrawerLayout layoutDrawer;
    private ActionBarDrawerToggle drawerToggler;
    private Stack<Fragment> stack;

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

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        stack = new Stack<Fragment>();
        layoutDrawer = (DrawerLayout) findViewById(R.id.layout_drawer);
        drawerToggler = new ActionBarDrawerToggle(this, layoutDrawer, toolbar,
                R.string.app_name, R.string.app_name);
        layoutDrawer.setDrawerListener(drawerToggler);

        setUpDrawerList();
        pushFragment(new FirstFragment(), true);

        Session.setContext(getApplicationContext());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (drawerToggler.isDrawerIndicatorEnabled()
                && drawerToggler.onOptionsItemSelected(item))
            return true;
        switch (item.getItemId()) {
        case android.R.id.home:
            Toast.makeText(this, "Back from activity", Toast.LENGTH_SHORT)
                    .show();
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        drawerToggler.syncState();
    }

    @Override
    public void onBackPressed() {
        popFragment();
    }

    private void setUpDrawerList() {
        ListView listView = (ListView) findViewById(R.id.list_drawer);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1,
                Arrays.asList(new String[] { "First Fragment",
                        "Second Fragment" }));
        listView.setAdapter(adapter);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                layoutDrawer.closeDrawers();
                drawerToggler.setDrawerIndicatorEnabled(false);
                getSupportActionBar().setDisplayHomeAsUpEnabled(true);
                pushFragment(getFragment(position), true);
            }
        });
    }

    private Fragment getFragment(int pos) {
        switch (pos) {
        case 0:
            return new FirstFragment();
        case 1:
            return new SecondFragment();
        }
        return null;
    }

    public void pushFragment(Fragment fragment, boolean add) {
        FragmentTransaction transation = getSupportFragmentManager()
                .beginTransaction();
        if (add)
            stack.push(fragment);
        transation.replace(R.id.layout_content, fragment);
        transation.commit();
    }

    public void popFragment() {
        if (!stack.isEmpty()) {
            Fragment fragment = stack.elementAt(stack.size() - 2);
            stack.pop();
            pushFragment(fragment, false);
        } else
            super.onBackPressed();
        drawerToggler.setDrawerIndicatorEnabled(stack.size() == 1);
    }

    public void clearBackStack() {
        stack.clear();
    }
}

第一个片段。Java语言

public class FirstFragment extends Fragment {

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        setHasOptionsMenu(true);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_first, container, false);
    }

    @Override
    public void onResume() {
        super.onResume();
        ActionBar actionBar = ((ActionBarActivity)getActivity()).getSupportActionBar();
        actionBar.setTitle("First Fragment");
        actionBar.setDisplayHomeAsUpEnabled(true);
        actionBar.setHomeButtonEnabled(true);
    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        super.onCreateOptionsMenu(menu, inflater);
        menu.clear();
        inflater.inflate(R.menu.fragment_menu, menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch(item.getItemId()) {
        case android.R.id.home:
            Toast.makeText(getActivity(), "Back from fragment", Toast.LENGTH_SHORT).show();
            getActivity().onBackPressed();
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

从上面的代码我无法得到的回调的android. r.id.home和设置主页按钮是不工作的每次actionBar.setDisplayHomeAsUpEn的（true）；actionBar.setHomeButtonEn的（true）；

任何帮助都将不胜感激。

谢谢

Answer 1

我有很多解决方案，但没有一个是完美的。我在我的项目中使用了各种可用的解决方案，如下所示。请在您初始化工具栏和抽屉布局的类中使用此代码。

getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
        @Override
        public void onBackStackChanged() {
            if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
                drawerFragment.mDrawerToggle.setDrawerIndicatorEnabled(false);
                getSupportActionBar().setDisplayHomeAsUpEnabled(true);// show back button
                toolbar.setNavigationOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        onBackPressed();
                    }
                });
            } else {
                //show hamburger
                drawerFragment.mDrawerToggle.setDrawerIndicatorEnabled(true);
                getSupportActionBar().setDisplayHomeAsUpEnabled(false);
                drawerFragment.mDrawerToggle.syncState();
                toolbar.setNavigationOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        drawerFragment.mDrawerLayout.openDrawer(GravityCompat.START);
                    }
                });
            }
        }
    });

Answer 2

您必须管理您在主活动上按下的后退按钮操作，因为您的主活动是您的片段的容器。

首先，将您的所有片段添加到transaction.addToBackStack（null），现在导航返回按钮调用将进行主要活动。我希望下面的代码能帮助你...

@Override
    public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case android.R.id.home:
        onBackPressed();
        }
    return super.onOptionsItemSelected(item);
}

您也可以使用

Fragment fragment =fragmentManager.findFragmentByTag(Constant.TAG); 
if(fragment!=null) {          
      FragmentTransaction transaction = fragmentManager.beginTransaction();
      transaction.remove(fragment).commit();
}

要根据fragment中的片段名称更改标题，可以使用以下代码：

activity.getSupportActionBar().setTitle("Keyword Report Detail");

Answer 3

将工具栏添加到xml

<android.support.v7.widget.Toolbar
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="?attr/colorPrimary"
    android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Fragment title"/>

</android.support.v7.widget.Toolbar>

然后在片段中的onCreateView方法中：

Toolbar toolbar = view.findViewById(R.id.toolbar);
toolbar.setNavigationIcon(R.drawable.ic_back_button);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
         getActivity().onBackPressed();
    }
});