Question

我创建了以下主要类，向用户显示了欢迎片段。这个欢迎片段有2个按钮：注册和登录。当用户点击注册按钮时，我希望他们路由到注册片段，当他们点击登录按钮时，用户需要转到登录片段。我面临的问题是单击按钮，没有任何事情发生。我的主要活动如下：

import android.content.Intent;
import android.content.res.Configuration;
import android.content.res.TypedArray;

import android.os.Bundle;
import android.support.v4.app.*;
import com.parse.Parse;
import com.parse.ParseAnalytics;
import android.util.Log;
import android.view.*;
import android.widget.*;

import java.util.ArrayList;

import android.support.v4.widget.DrawerLayout;
import com.parse.ParseObject;
import com.project.iandwe.Adaptor.NavigationDrawerListAdapter;
import com.project.iandwe.Fragments.UserLogIn;
import com.project.iandwe.Fragments.UserSignUp;
import com.project.iandwe.Fragments.WelcomePage;
import com.project.iandwe.Menu.*;
import com.project.iandwe.Navigation.NavigationDrawer;

public class MainActivity extends FragmentActivity implements Communicator {
@Override
    protected void onCreate(Bundle savedInstanceState) {
WelcomePage welcomePage = new WelcomePage();
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.fragmentWelcome,welcomePage);
        fragmentTransaction.show(welcomePage);
        fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentLogin));
        fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentISignUp));
        fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentRegister));
        fragmentTransaction.commit();
}

@Override
    public void respond(int button) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        if (button == 1) {
            UserSignUp userSignUp = (UserSignUp) fragmentManager.findFragmentById(R.id.fragmentISignUp);
            fragmentTransaction.replace(R.id.fragmentISignUp, userSignUp);
            fragmentTransaction.show(userSignUp);
            fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentLogin));
            fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentWelcome));
            fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentRegister));
        } else if (button == 2) {
            UserLogIn userLogIn = (UserLogIn) fragmentManager.findFragmentById(R.id.fragmentLogin);
            fragmentTransaction.replace(R.id.fragmentLogin, userLogIn);
            fragmentTransaction.show(userLogIn);
            fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentISignUp));
            fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentWelcome));
            fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentRegister));
        }
        fragmentTransaction.commit();

    }

我的片段看起来像这样：

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import com.project.iandwe.Communicator;
import com.project.iandwe.R;

/**
 * Created by NathanDrake on 5/28/2014.
 */
public class WelcomePage extends Fragment implements View.OnClickListener {
    Button login,signUp;
    int buttonFlag =0;
    Communicator communicator;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
           View layoutInflater;
           layoutInflater=inflater.inflate(R.layout.welcome_page,container, false );
      /*  login = (Button) getActivity().findViewById(R.id.buttonLogin);
        signUp = (Button) getActivity().findViewById(R.id.buttonSignUp);
        communicator = (Communicator) getActivity();

        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                buttonFlag =1;
                communicator.respond(buttonFlag);
            }
        });

        signUp.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                buttonFlag =2;
                communicator.respond(buttonFlag);
            }
        });
        communicator.respond(buttonFlag); */
           return layoutInflater;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        login = (Button) getActivity().findViewById(R.id.buttonLogin);
        signUp = (Button) getActivity().findViewById(R.id.buttonSignUp);
        communicator = (Communicator) getActivity();
        login.setOnClickListener(this);
        signUp.setOnClickListener(this);
        /*

        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
             buttonFlag =1;
                communicator.respond(buttonFlag);
            }
        });

        signUp.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                buttonFlag =2;
                communicator.respond(buttonFlag);
            }
        });

        communicator.respond(buttonFlag); */
     }


    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.buttonLogin:
                buttonFlag =1;
                break;
            case R.id.buttonSignUp:
                buttonFlag =2;
            break;

        }
        communicator.respond(buttonFlag);
    }
}

Communicator是一个用于片段间通信的简单接口，如下所示：

public interface Communicator {

    public void respond(int button);
}

我尝试了此处给出的方法，但仍然没有来自片段的响应：How to handle button clicks using the xml onClick within Fragments

请看一下，让我知道我在这里缺少什么。

更新：

我将代码更改为包含片段引用，如下所示：

   welcomePage = new WelcomePage();
            FragmentManager fragmentManager = getSupportFragmentManager();
            userLogIn = (UserLogIn) fragmentManager.findFragmentById(R.id.fragmentLogin);
            userSignUp = (UserSignUp) fragmentManager.findFragmentById(R.id.fragmentISignUp);
            registerUsingEmail = (RegisterUsingEmail) fragmentManager.findFragmentById(R.id.fragmentRegister);

fragmentTransaction.hide(userLogIn);
        //fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentISignUp));
        fragmentTransaction.hide(userSignUp);
        //fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentRegister));
        fragmentTransaction.hide(registerUsingEmail);
        fragmentTransaction.commit();

并更新了我对沟通者的回应功能：

@Override
    public void respond(int button) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.hide(welcomePage);
        fragmentTransaction.remove(welcomePage);
        fragmentTransaction.commit();
        fragmentManager.executePendingTransactions();
        fragmentTransaction = fragmentManager.beginTransaction();
        if (button == 1) {
           // userSignUp = (UserSignUp) fragmentManager.findFragmentById(R.id.fragmentISignUp);

            fragmentTransaction.remove(userSignUp);
            fragmentTransaction.commit();
            fragmentManager.executePendingTransactions();
            fragmentTransaction = fragmentManager.beginTransaction();
            fragmentTransaction.add(R.id.fragmentISignUp, userSignUp);
            Toast.makeText(getApplicationContext(),"You are inside user signup Button",Toast.LENGTH_LONG).show();
            fragmentTransaction.show(userSignUp);
            //fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentLogin));
            fragmentTransaction.hide(userLogIn);
            //fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentWelcome));

            //fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentRegister));
            fragmentTransaction.hide(registerUsingEmail);
        } else if (button == 2) {
         //   userLogIn = (UserLogIn) fragmentManager.findFragmentById(R.id.fragmentLogin);

            fragmentTransaction.remove(userLogIn);
            fragmentTransaction.commit();
            fragmentManager.executePendingTransactions();
            fragmentTransaction = fragmentManager.beginTransaction();
            fragmentTransaction.add(R.id.fragmentLogin, userLogIn);
            Toast.makeText(getApplicationContext(),"You are inside user login Button",Toast.LENGTH_LONG).show();
            fragmentTransaction.show(userLogIn);
            //fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentISignUp));
            fragmentTransaction.hide(userSignUp);
            //fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentWelcome));

          //  fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentRegister));
            fragmentTransaction.hide(registerUsingEmail);
        }
        fragmentTransaction.commit();

    }

我现在面临的问题是我没有看到现有的欢迎片段被usersign或userlogin片段替换..我包含了toast消息以查看代码是否正在运行，并且我在响应方法时看到这些消息按钮调用，但我没有看到用户界面更新。我检查了move fragments并尝试了所有内容，但没有任何工作

Answer 1

问题是您使用的是不同响应的Communicator接口，您只应使用Communicator的一个实例，因此需要将其传递给主活动中的片段。

并且在mainactivity接口中只会被调用..也不会对片段实现Communicator，只有Communicator将实现mainactivity ..并将其传递给片段构造函数

Answer 2

根据它的外观，您实际上从未将Fragments添加到Activity，只需调用隐藏方法。

MainActivity中的案例和点：

FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.add(R.id.fragmentWelcome,welcomePage);
fragmentTransaction.show(welcomePage);

// These are never added, you just hide them
fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentLogin));
fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentISignUp));
fragmentTransaction.hide(fragmentManager.findFragmentById(R.id.fragmentRegister));
fragmentTransaction.commit();

如果我们在hide中检查FragmentTransaction方法的documentation，我们可以看到只是隐藏未附加的内容就不会做任何事情。您应该创建Fragments的实例并以与WelcomePage类似的方式添加它们，然后隐藏它们。

我也发现您错误地使用了某些FragmentTransaction方法。快速摘要hide和show用于简单地更改Fragment是否仍然可见（换句话说，它不会与Activity分离）。但是，replace方法会分离它在给定Fragment处找到的id，并将输入的“片段”附加到其位置。

OnClick for按钮不更新片段

2 个答案: