Android 如何为每个选项卡刷新ViewPager？

我使用ViewPager作为主布局，对于单个页面视图，我使用片段。这些选项卡是操作栏的一部分。 我想用操作栏中的刷新按钮刷新当前选项卡

My MainActivity.java

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


    viewPager = (ViewPager) findViewById(R.id.pager);
    actionBar = getActionBar();
    mAdapter = new TabsPagerAdapter(getSupportFragmentManager());

    viewPager.setAdapter(mAdapter);
    actionBar.setHomeButtonEnabled(false);
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);  

    // Adding Tabs
    for (String tab_name : tabs) {
        actionBar.addTab(actionBar.newTab().setText(tab_name)
                .setTabListener(this));
    }

    /**
     * on swiping the viewpager make respective tab selected
     * */
    viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

        @Override
        public void onPageSelected(int position) {
            // on changing the page
            // make respected tab selected
            actionBar.setSelectedNavigationItem(position);
            mAdapter.notifyDataSetChanged();
        }

        @Override
        public void onPageScrolled(int arg0, float arg1, int arg2) {
        }

        @Override
        public void onPageScrollStateChanged(int arg0) {
        }
    });
}


@Override
public boolean onOptionsItemSelected(MenuItem menuItem)
{     
    switch (menuItem.getItemId()) {


    case R.id.action_refresh:

         // code for the refresh             

        return true;

    default:
        this.finish();

        return super.onOptionsItemSelected(menuItem);
    }
    //startActivity(new Intent(this,PreviousActivity.class)); 
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.activity_actions, menu);

    return super.onCreateOptionsMenu(menu);
}

@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}

@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
    // on tab selected
    // show respected fragment view
    viewPager.setCurrentItem(tab.getPosition());
}

@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}

这是我的一个标签 StartPage.java

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

    View rootView = inflater.inflate(R.layout.startpage, container, false);
    return rootView;
}



@Override
public void onTabReselected(Tab arg0, FragmentTransaction arg1) {
    // TODO Auto-generated method stub

}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub

}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub

}

---

一种方法是在操作栏中找到所选选项卡，将其强制转换为其类型，然后对其调用方法

这是您可能希望避免的依赖关系

我更喜欢在这个场景中使用广播。在fragments onResume方法中注册广播接收器，在onPause中取消注册。然后让上下文广播刷新的意图，片段就会这样做

这将允许您刷新应用程序中任何地方的片段。即使刷新代码最终出现在后台运行的服务中

更新：

您可以在任何地方使用类似的代码（

this

is's context）：

然后在您的片段中收听此广播：

public class MyFragment extends Fragment {

    MyReceiver r;

    public void refresh() {
        // Do the refresh
    }

    public void onPause() {
        LocalBroadcastManager.getInstance(mContext).unregisterReceiver(r);
    }

    public void onResume() {
        r = new MyReceiver ();
        LocalBroadcastManager.getInstance(mContext).registerReceiver(r,
            new IntentFilter(REFRESH_CONSTANT));
    }

    private class MyReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            MyFragment.this.refresh();
        }
    }
}

public class MyFragment extends Fragment {

    MyReceiver r;

    public void refresh() {
        // Do the refresh
    }

    public void onPause() {
        LocalBroadcastManager.getInstance(mContext).unregisterReceiver(r);
    }

    public void onResume() {
        r = new MyReceiver ();
        LocalBroadcastManager.getInstance(mContext).registerReceiver(r,
            new IntentFilter(REFRESH_CONSTANT));
    }

    private class MyReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            MyFragment.this.refresh();
        }
    }
}