Question

我是Android的新手，并试图自己学习。但我正在与Fragments度过艰难时期。我正在创建一个简单的应用程序来学习片段。我认为这看起来很愚蠢，但我真的无法让它发挥作用。

我想要做的只是点击Fragment_One中的按钮（buttonSayHi），Fragment_One应该被Fragment_Two取代。

我不确定何时调用Fragment代码以及我应该在哪里编写代码来调用第二个片段。我收到错误：无法启动Activity组件。

但是，如果我丢弃按钮的监听器并且片段显示在活动中，则代码可以正常工作。

我做了大量研究，阅读developer.android.com上的片段教程以及Lars Vogella的教程。我认为我的概念不明确。

任何帮助将不胜感激。

以下是代码：

activity_main.xml中

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/frameLayoutFragmentContainer"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

</FrameLayout>

fragment_one.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <EditText
        android:id="@+id/editTextPersonName"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="textPersonName" >

        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/buttonSayHi"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Say Hi" 
        android:onClick="onButtonClicked"/>

</LinearLayout>

fragment_two.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/textViewResult"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="I will say Hi!" />

</LinearLayout>

MainActivity.java

package com.example.fragmenttutorial;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;

public class MainActivity extends Activity{

    View view;
    FragmentManager fragmentManager = getFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

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

        Fragment fragmentOne = new FragmentOne();

        fragmentTransaction.add(R.id.frameLayoutFragmentContainer, fragmentOne);
        fragmentTransaction.addToBackStack(null);

        fragmentTransaction.commit();
    }

    protected void onButtonClicked()
    {
        if(view.getId() == R.id.buttonSayHi){
            Fragment fragmentTwo = new FragmentTwo();

            fragmentTransaction.replace(R.id.frameLayoutFragmentContainer, fragmentTwo);
            fragmentTransaction.addToBackStack(null);

            fragmentTransaction.commit();   

        }

    }
}

FragmentOne.java

package com.example.fragmenttutorial;

import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class FragmentOne extends Fragment{

    View view;
    FragmentManager fragmentManager = getFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

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

        View view = inflater.inflate(R.layout.fragment_one, container, false);
        return view;
    }

//  protected void onButtonClicked()
//  {
//      if(view.getId() == R.id.buttonSayHi){
//          Fragment fragmentTwo = new FragmentTwo();
//
//          fragmentTransaction.replace(R.id.frameLayoutFragmentContainer, fragmentTwo);
//          fragmentTransaction.addToBackStack(null);
//
//          fragmentTransaction.commit();   
//
//      }
//
//  }
}

我已经在片段中注释了点击代码。我也尝试在片段中实现onClickListener。

FragmentTwo.java

package com.example.fragmenttutorial;

import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class FragmentTwo extends Fragment{

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

        View view = inflater.inflate(R.layout.fragment_two, container, false);
        return view;    
    }
}

编辑：我已经从我的XML代码中删除了android：onClick =“onButtonClicked”这一行。并编辑了以下文件，但它仍然无法正常工作。你能为我提供一个没有android：onClick =“onButtonClicked”行的工作示例。

MainActivity.java

package com.example.fragmenttutorial;

import android.os.Bundle;
import android.view.View;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;

public class MainActivity extends Activity{

    View view;
    Fragment fragmentOne;
    FragmentManager fragmentManager = getFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

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

        fragmentOne = new FragmentOne();

        fragmentTransaction.add(R.id.frameLayoutFragmentContainer, fragmentOne);
        fragmentTransaction.addToBackStack(null);

        fragmentTransaction.commit();       
    }
}

FragmentOne.java

package com.example.fragmenttutorial;

import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;

public class FragmentOne extends Fragment implements OnClickListener{

    View view;
    Fragment fragmentTwo;
    FragmentManager fragmentManager = getFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

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

        View view = inflater.inflate(R.layout.fragment_one, container, false);
        Button buttonSayHi = (Button) view.findViewById(R.id.buttonSayHi);
        buttonSayHi.setOnClickListener(this);
        return view;
    }

    @Override
    public void onClick(View v) {

        fragmentTwo = new FragmentTwo();

        fragmentTransaction.replace(R.id.frameLayoutFragmentContainer, fragmentTwo);
        fragmentTransaction.addToBackStack(null);

        fragmentTransaction.commit();   

    }
}

感谢您提出宝贵的建议。

Answer 1

您的片段类应该实现OnClickListener

public class SmartTvControllerFragment extends Fragment implements View.OnClickListener

然后获取视图，链接按钮并设置onClickListener，如下面的示例

 View view;

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

    view = inflater.inflate(R.layout.smart_tv_controller_fragment, container, false);
    upButton = (Button) view.findViewById(R.id.smart_tv_controller_framgment_up_button);
    upButton.setOnClickListener(this);
    return view;
 }

然后添加onClickListener方法并执行您想要的操作。

@Override
public void onClick(View v) {
 //do what you want to do when button is clicked
    switch (v.getId()) {
        case R.id.textView_help:
            switchFragment(HelpFragment.TAG);
            break;
        case R.id.textView_settings:
            switchFragment(SettingsFragment.TAG);
            break;
    }
}

这是我的代码示例，但我希望您理解

Answer 2

使用您的代码

public class FragmentOne extends Fragment implements OnClickListener{

    View view;
    Fragment fragmentTwo;
    FragmentManager fragmentManager = getFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

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

        View view = inflater.inflate(R.layout.fragment_one, container, false);
        Button buttonSayHi = (Button) view.findViewById(R.id.buttonSayHi);
        buttonSayHi.setOnClickListener(this);
        return view;
    }

但我认为以这种方式更好地处理按钮：

@Override
    public void onClick(View v) {
        switch(v.getId()){
            case R.id.buttonSayHi:
            /** Do things you need to..
               fragmentTwo = new FragmentTwo();

               fragmentTransaction.replace(R.id.frameLayoutFragmentContainer, fragmentTwo);
               fragmentTransaction.addToBackStack(null);

               fragmentTransaction.commit();  
            */
            break;
        }   
    }

Answer 3

片段监听器

如果fragment需要events与activity进行通信，则fragment应将interface定义为内部类型，并要求activity 1}}必须implement此interface：

import android.support.v4.app.Fragment;

public class MyListFragment extends Fragment {
  // ...
  // Define the listener of the interface type
  // listener is the activity itself
  private OnItemSelectedListener listener;

  // Define the events that the fragment will use to communicate
  public interface OnItemSelectedListener {
    public void onRssItemSelected(String link);
  }

  // Store the listener (activity) that will have events fired once the fragment is attached
  @Override
  public void onAttach(Activity activity) {
    super.onAttach(activity);
      if (activity instanceof OnItemSelectedListener) {
        listener = (OnItemSelectedListener) activity;
      } else {
        throw new ClassCastException(activity.toString()
            + " must implement MyListFragment.OnItemSelectedListener");
      }
  }

  // Now we can fire the event when the user selects something in the fragment
  public void onSomeClick(View v) {
     listener.onRssItemSelected("some link");
  }
}

然后在activity：

import android.support.v4.app.FragmentActivity;

public class RssfeedActivity extends FragmentActivity implements
  MyListFragment.OnItemSelectedListener {
    DetailFragment fragment;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_rssfeed);
      fragment = (DetailFragment) getSupportFragmentManager()
            .findFragmentById(R.id.detailFragment);
  }

  // Now we can define the action to take in the activity when the fragment event fires
  @Override
  public void onRssItemSelected(String link) {
      if (fragment != null && fragment.isInLayout()) {
          fragment.setText(link);
      }
  }
}

Answer 4

您只需要查看带有此片段的活动视图，这只有在您的片段已经创建时才会发生

覆盖片段中的onViewCreated()方法并享受其魔力:) ..

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    Button button = (Button) view.findViewById(R.id.YOURBUTTONID);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
         //place your action here
         }
    });

希望这可以帮到你;

Answer 5

当您在XML中声明onclick时，您必须声明方法并将View v作为参数传递并将该方法设为公共...

Ex:
//in xml
android:onClick="onButtonClicked"


// in java file
public void onButtonClicked(View v)
{
//your code here
}

Answer 6

    //sure run it i will also test it
//we make a class that extends with the fragment
    public class Example_3_1 extends Fragment  implements OnClickListener
    {
       View vi;
        EditText t;
        EditText t1;
        Button bu;
 // that are by defult function of fragment extend class
     @Override
       public View onCreateView(LayoutInflater inflater,ViewGroup container,BundlesavedInstanceState) 
       {        
           vi=inflater.inflate(R.layout.example_3_1, container, false);// load the xml file 
           bu=(Button) vi.findViewById(R.id.button1);// get button id from example_3_1 xml file
           bu.setOnClickListener(this); //on button appay click listner
           t=(EditText) vi.findViewById(R.id.editText1);// id get from example_3_1 xml file
           t1=(EditText) vi.findViewById(R.id.editText2);
          return vi; // return the view object,that set the xml file  example_3_1 xml file
       }
       @Override
       public void onClick(View v)//on button click that called
       {

          switch(v.getId())// on run time get id what button os click and get id
          {
          case R.id.button1:        // it mean if button1 click then this work
           t.setText("UMTien");     //set text 
           t1.setText("programming");
           break;
          }
    }     }

Answer 7

这适合我。

private OnClickListener mDisconnectListener;
mDisconnectListener = new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

        }
    };

...

... onCreateView(...){

mButtonDisconnect = (Button) rootView.findViewById(R.id.button_disconnect);
mButtonDisconnect.setOnClickListener(mDisconnectListener);
...
}

Answer 8

试试这个：

FragmentOne.java

import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

public class FragmentOne extends Fragment{

    View rootView;        

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

        rootView = inflater.inflate(R.layout.fragment_one, container, false);


        Button button = (Button) rootView.findViewById(R.id.buttonSayHi);
        button.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                onButtonClicked(v);
            }
        });
        return rootView;
    }

  public void onButtonClicked(View view)
  {
          //do your stuff here..           
    final FragmentTransaction ft = getFragmentManager().beginTransaction(); 
    ft.replace(R.id.frameLayoutFragmentContainer, new FragmentTwo(), "NewFragmentTag"); 
    ft.commit(); 

    ft.addToBackStack(null);    
  }
}

检查一下：click here

Answer 9

只需将视图对象传递给onButtonClicked函数即可。 getView（）似乎在片段内没有按预期工作。尝试使用FragmentOne片段的代码

PS。您已在原始FragmentOne代码中重新定义了对象视图。

package com.example.fragmenttutorial;

import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class FragmentOne extends Fragment{

    FragmentManager fragmentManager = getFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

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

        View view = inflater.inflate(R.layout.fragment_one, container, false);
        onButtonClicked(view);
        return view;
    }

  protected void onButtonClicked(View view)
  {
      if(view.getId() == R.id.buttonSayHi){
          Fragment fragmentTwo = new FragmentTwo();

          fragmentTransaction.replace(R.id.frameLayoutFragmentContainer, fragmentTwo);
          fragmentTransaction.addToBackStack(null);

          fragmentTransaction.commit();   

     }

按钮监听器在android中的片段中的按钮

9 个答案:

FragmentOne.java