Java 在单个活动中动态实现多个片段

Implementing multiple fragments in a single activity Dynamically

提问by smriti3

I am working on fragments

我正在处理片段

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Use case i am trying to implement::

我正在尝试实施的用例::

• I am using dynamic fragments
• I am using three fragments in a single activity
• my goal is to communicate between all the three fragments
• I am using support package for fragments

• 我正在使用动态片段
• 我在一个活动中使用了三个片段
• 我的目标是在所有三个片段之间进行交流
• 我正在使用片段支持包

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Each fragment has a single widget

每个片段都有一个小部件

• my_fragment1has edittext
• my_fragment2has button
• my_fragment3has TextView

• my_fragment1已 edittext
• my_fragment2已 button
• my_fragment3已 TextView

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On click of buttonthe text from the edittextmust be displayed in the textview

单击 中button的文本edittext必须显示在textview

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What i have tried so far i have constructed most of the scenario below

到目前为止我已经尝试过我已经构建了下面的大部分场景

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Top_Fragment.java

Top_Fragment.java

public class Top_Fragment extends Fragment{

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // TODO Auto-generated method stub

        View view=inflater.inflate(R.layout.my_fragment1, container, false);

        return view;
    }
}

Middle_Fragment.java

Middle_Fragment.java

package com.example.deleteme;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;

public class Middle_Fragment extends Fragment{

    View view;
    Button btn;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // TODO Auto-generated method stub

        view=inflater.inflate(R.layout.my_fragment2, container, false);
        btn=(Button) view.findViewById(R.id.button1);
        btn.setOnClickListener(new OnClickListener() {

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



            }
        });
        return view;
    }
}

Bottom_Fragment.java

底部_片段.java

public class Bottom_Fragment extends Fragment{

    View view;
    TextView display_text;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        view=inflater.inflate(R.layout.my_fragment3, container,false);
        display_text=(TextView) view.findViewById(R.id.editText1);
        return view;
    }

    public void setName(String Name){
        display_text.setText("Result::" + Name);
    }



}

MainActivity.java

主活动.java

public class MainActivity extends FragmentActivity {

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

        Top_Fragment frg=new Top_Fragment();//create the fragment instance for the top fragment
        Middle_Fragment frg1=new Middle_Fragment();//create the fragment instance for the middle fragment
        Bottom_Fragment frg2=new Bottom_Fragment();//create the fragment instance for the bottom fragment

        FragmentManager manager=getSupportFragmentManager();//create an instance of fragment manager

        FragmentTransaction transaction=manager.beginTransaction();//create an instance of Fragment-transaction

        transaction.add(R.id.My_Container_1_ID, frg, "Frag_Top_tag");
        transaction.add(R.id.My_Container_2_ID, frg1, "Frag_Middle_tag");
        transaction.add(R.id.My_Container_3_ID, frg2, "Frag_Bottom_tag");


        transaction.commit();

    }


}

activity_main.xml

活动_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    tools:context=".MainActivity" 
    android:background="@color/black">

    <FrameLayout
        android:id="@+id/My_Container_1_ID"
        android:layout_width="fill_parent"
        android:layout_height="150dp" 
        android:background="@color/yellow">
    </FrameLayout>

    <FrameLayout
        android:id="@+id/My_Container_2_ID"
        android:layout_width="fill_parent"
        android:layout_height="150dp"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/My_Container_1_ID"
        android:background="@color/Orange" >
    </FrameLayout>

    <FrameLayout
        android:id="@+id/My_Container_3_ID"
        android:layout_width="fill_parent"
        android:layout_height="150dp"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/My_Container_2_ID"
        android:background="@color/purple" >
    </FrameLayout>

</RelativeLayout>

my_fragment1.xml

my_fragment1.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@color/green" >

    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:ems="10"
        android:textColor="#000000"
        android:singleLine="true" >

        <requestFocus />
    </EditText>

</RelativeLayout>

my_fragment2.xml

my_fragment2.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" 
    android:background="@color/pink">

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:background="@color/black"
        android:text="Button"
        android:textColor="#FFFFFF" />

</RelativeLayout>

my_fragment3.xml

my_fragment3.xml

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

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="TextView"
        android:textColor="#000000"
        android:textSize="30dp" />

</RelativeLayout>

My output is Like below::

我的输出如下::

---

---

What I am having problem in achieving::

我在实现方面遇到的问题::

• I am not able to set the value obtained from edit textto textviewon click of the button

• 我不能够设置从获得的值edit text来 textview上的点击button

Any Ideas?

有任何想法吗？

采纳答案by Raghunandan

All Fragment-to-Fragment communication is done through the associated Activity. Two Fragments should never communicate directly.

所有 Fragment 到 Fragment 的通信都是通过关联的 Activity 完成的。两个 Fragment 永远不应该直接通信。

http://developer.android.com/training/basics/fragments/communicating.html

http://developer.android.com/training/basics/fragments/communicating.html

test.java// in your case its MainActivity

test.java//在你的情况下 MainActivity

public class test extends FragmentActivity implements textEntered {

    String value;
    boolean check = false;
    BottomFragment frg2;
    FragmentTransaction transaction;

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

        Top_Fragment frg = new Top_Fragment();
        frg2 = new BottomFragment();

        FragmentManager manager = getSupportFragmentManager();
        transaction = manager.beginTransaction();
        transaction.add(R.id.My_Container_1_ID, frg, "Frag_Top_tag");
        transaction.add(R.id.My_Container_3_ID, frg2, "Frag_Bottom_tag");
        transaction.commit();
    }

    @Override
    public void setValue(String editextvalue) {
        value = editextvalue;
        if (frg2 != null) {
            frg2.setName(value);
        } else {
            Toast.makeText(getApplicationContext(), "fragment 2  is null", 1000).show();
        }
    }

}    

Top_Fragment.java

Top_Fragment.java

public class Top_Fragment extends Fragment {
    textEntered mCallback;
    Button b;
    EditText ed;

    public interface textEntered {
        public void setValue(String editextvalue);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
        // TODO Auto-generated method stub

        View view = inflater.inflate(R.layout.my_fragment1, container, false);
        ed = (EditText) view.findViewById(R.id.editText1);


        return view;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onActivityCreated(savedInstanceState);
        b = (Button) getView().findViewById(R.id.button1);
        b.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                String s = ed.getText().toString();
                mCallback.setValue(s);
            }

        });
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);

        // This makes sure that the container activity has implemented
        // the callback interface. If not, it throws an exception
        try {
            mCallback = (textEntered) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString() +
                " must implement textEntered");
        }
    }
}

my_fragment1.xml

my_fragment1.xml

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

    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:ems="10"
        android:textColor="#000000"
        android:singleLine="true" >

        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editText1"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="20dp"
        android:text="Button" />

</RelativeLayout>

Change to

改成

 display_text=(TextView) view.findViewById(R.id.textView1);
 // id is textView 1 not editText1

in BottomFragment

在底部片段中

snap

折断

回答by Ivo Beckers

You can use the Activity for that.

您可以为此使用活动。

in the onClick of the bottom fragment you can do something like

在底部片段的 onClick 中，您可以执行以下操作

((MainActivity) getActivity()).doIt();

((MainActivity) getActivity()).doIt();

And make a method doItin your MainActivitymaybe something like this

并doIt在你的MainActivity也许是这样的事情中制定一个方法

public void doIt(){
    frg2.setName(frg.getText())
}

and in the top fragment make a method getTextthat returns the text of the EditText

并在顶部片段中创建一个getText返回 EditText 文本的方法

回答by Amaan Memon

Communication between Fragments

片段之间的通信

There can be many scenarios where communication between fragment is required. You need to pass data between fragments on button click event. You may also use Android toolbar to switch between fragments. When you add buttons to your toolbar, you need to dynamically change screen using fragment.

可能有很多场景需要片段之间的通信。您需要在按钮单击事件的片段之间传递数据。您也可以使用 Android 工具栏在片段之间切换。当您向工具栏添加按钮时，您需要使用片段动态更改屏幕。

Create an interfacewhich will help us to communicate

创建一个有助于我们交流的界面

Communicate.java

沟通.java

package com.example.amaanmemon.testfragment;

interface Communicate {
 public void sendData();
}

TopFragment.java

TopFragment.java

package com.example.amaanmemon.testfragment;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;

public class TopFragment extends Fragment {

EditText  firstName;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // TODO Auto-generated method stub

    View view=inflater.inflate(R.layout.my_fragment1, container, false);
    return view;
}

public void onActivityCreated(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onActivityCreated(savedInstanceState);
    firstName = (EditText) getActivity().findViewById(R.id.editText1);
}

public String getData(){
    return firstName.getText().toString();
}
}

MiddleFragment.java

中间片段.java

package com.example.amaanmemon.testfragment;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;

public class MiddleFragment extends Fragment implements OnClickListener{

View view;
Button btn;
Communicate cm;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    view=inflater.inflate(R.layout.my_fragment2, container, false);
    return  view;
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onActivityCreated(savedInstanceState);
    cm = (Communicate) getActivity();
    btn = (Button) getActivity().findViewById(R.id.button1);
    btn.setOnClickListener(this);
}

@Override
public void onClick(View arg0) {
    // TODO Auto-generated method stub
    cm.sendData();
}
}

BottomFragment.java

底部片段.java

package com.example.amaanmemon.testfragment;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

public class BottomFragment extends Fragment{

int count;
View view;
TextView display_text;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    view=inflater.inflate(R.layout.my_fragment3, container,false);
    return view;
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onActivityCreated(savedInstanceState);
    display_text = (TextView)getActivity().findViewById(R.id.textView1);
}

public void incrementData(String displayText){
    display_text.setText(displayText);
}
}

MainActivity.java

主活动.java

package com.example.amaanmemon.testfragment;

import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;

public class MainActivity extends FragmentActivity implements Communicate{

TopFragment frg;
MiddleFragment frg1;
BottomFragment frg2;
FragmentTransaction transaction;

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

    frg = new TopFragment();
    frg1 = new MiddleFragment();
    frg2 = new BottomFragment();

    FragmentManager manager=getSupportFragmentManager();
    transaction=manager.beginTransaction();
    transaction.add(R.id.My_Container_1_ID, frg, "Frag_Top_tag");
    transaction.add(R.id.My_Container_2_ID, frg1, "Frag_Middle_tag");
    transaction.add(R.id.My_Container_3_ID, frg2, "Frag_Bottom_tag");
    transaction.commit();
}

@Override
public void sendData() {
    String temp = frg.getData();
    frg2.incrementData(temp);
}
}

You can copy xml files from question. you can watch the output below.

您可以从问题中复制 xml 文件。您可以观看下面的输出。