工作代码:

package com.example.keralapolice;

import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentManager.OnBackStackChangedListener;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.Gravity;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

public class ChiefFragment extends Fragment {
    View view;

    // public OnBackPressedListener onBackPressedListener;

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

        view = inflater.inflate(R.layout.activity_chief, container, false);
        getActivity().getActionBar().hide();
        view.setFocusableInTouchMode(true);
        view.requestFocus();
        view.setOnKeyListener(new View.OnKeyListener() {
            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                Log.i(getTag(), "keyCode: " + keyCode);
                if (keyCode == KeyEvent.KEYCODE_BACK) {
                    getActivity().getActionBar().show();
                    Log.i(getTag(), "onKey Back listener is working!!!");
                    getFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
                    // String cameback="CameBack";
                    Intent i = new Intent(getActivity(), home.class);
                    // i.putExtra("Comingback", cameback);
                    startActivity(i);
                    return true;
                } else {
                    return false;
                }
            }
        });
        return view;
    }
}

在fragment类中，为back event放以下代码:

 rootView.setFocusableInTouchMode(true);
        rootView.requestFocus();
        rootView.setOnKeyListener( new OnKeyListener()
        {
            @Override
            public boolean onKey( View v, int keyCode, KeyEvent event )
            {
                if( keyCode == KeyEvent.KEYCODE_BACK )
                {
                    FragmentManager fragmentManager = getFragmentManager();
                    fragmentManager.beginTransaction()
                            .replace(R.id.frame_container, new Book_service_provider()).commit();

                    return true;
                }
                return false;
            }
        } );

你可以使用from getActionBar().setDisplayHomeAsUpEnabled():

@Override
public void onBackStackChanged() {
    int backStackEntryCount = getFragmentManager().getBackStackEntryCount();

    if(backStackEntryCount > 0){
        getActionBar().setDisplayHomeAsUpEnabled(true);
    }else{
        getActionBar().setDisplayHomeAsUpEnabled(false);
    }
}

如果您管理将每个事务添加到后退堆栈的流程，那么您可以这样做，以便在用户按后退按钮时显示上一个片段(您也可以映射home按钮)。

@Override
public void onBackPressed() {
    if (getFragmentManager().getBackStackEntryCount() > 0)
        getFragmentManager().popBackStack();
    else
        super.onBackPressed();
}

在看了所有的解决方案后，我意识到有一个更简单的解决方案。

在你的活动的onBackPressed()托管你所有的片段，找到你想要防止反压的片段。如果找到了，就返回。那么popBackStack将永远不会发生在这个片段上。

  @Override
public void onBackPressed() {

        Fragment1 fragment1 = (Fragment1) getFragmentManager().findFragmentByTag(“Fragment1”);
        if (fragment1 != null)
            return;

        if (getFragmentManager().getBackStackEntryCount() > 0){
            getFragmentManager().popBackStack();

        }
}

如果你重写了片段视图的onKey方法，你需要:

    view.setFocusableInTouchMode(true);
    view.requestFocus();
    view.setOnKeyListener(new View.OnKeyListener() {
            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                Log.i(tag, "keyCode: " + keyCode);
                if( keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_UP) {
                    Log.i(tag, "onKey Back listener is working!!!");
                    getFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
                    return true;
                } 
                return false;
            }
        });