Question

我是android的初学者，正在测试RecyclerView.Following是我的片段：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.recyclerviewtest.RecyclerTestActivity" >

<android.support.v7.widget.RecyclerView
    android:layout_height="match_parent"
    android:layout_width="wrap_content"
    android:id="@+id/drawer"
  >

</android.support.v7.widget.RecyclerView>

</RelativeLayout>

以下是我的MainActivity.java类

package com.example.recyclerviewtest;

import android.app.Activity;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.os.StrictMode;

public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    if(savedInstanceState == null)
    {
        FragmentManager manager = getFragmentManager();
        FragmentTransaction transaction = manager.beginTransaction();
        transaction.replace(R.id.container, new      RecyclerTestActivity()).commit();
    if (android.os.Build.VERSION.SDK_INT > 9) {
          StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
          StrictMode.setThreadPolicy(policy);
        }
}
}
}

这是main_activity_xml：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="${relativePackage}.${activityClass}" 
android:orientation="horizontal">

 <fragment 
    android:layout_width="match_parent"
    android:layout_height="match_parent" 
    android:id="@+id/container"      
    />
</LinearLayout>

但是在片段中的主要活动中附加片段时：

 transaction.replace(R.id.container, new     RecyclerTestActivity()).commit();

我收到错误：

The method replace is not applicable for (int,RecyclerTestActivity)

有人可以帮助我。

编辑：RecyclerTestActivity Fragment的代码是：

package com.example.recyclerviewtest;

import java.util.ArrayList;
import java.util.List;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;


public class RecyclerTestActivity extends Fragment {
private Adapter adapter;
private RecyclerView recyclerview;
@Override
public View onCreateView(LayoutInflater inflater,
        @Nullable ViewGroup container, @Nullable Bundle savedInstanceState)     {
    View Layout = inflater.inflate(R.layout.activity_recycler_test,container,false);
    recyclerview=(RecyclerView)Layout.findViewById(R.id.drawer);
    adapter=new Adapter(getActivity(), getdata());
    recyclerview.setAdapter(adapter);
    recyclerview.setLayoutManager(new LinearLayoutManager(getActivity()));

    return Layout;
}

public List<Information> getdata()
{
    List<Information> items = new ArrayList<>();
    int[] data ={R.drawable.ic_launcher,R.drawable.ic_launcher,R.drawable.ic_launcher};
    String[] content={"One","Two","Three"};

    for(int i=0;i<data.length;i++)
    {
        Information current = new Information();
        current.desc=content[i];
        current.number=data[i];
        items.add(current);
    }

    return items;

}

}

Answer 1

你的问题在于这一行：
transaction.replace(R.id.container, new RecyclerTestActivity()).commit();

这应该是transaction.replace(R.id.container, fragment).commit(); 而不是Fragment，而是Activity。

同样在您的xml中，您使用的是<fragment>标记。而是使用某些布局，例如<FrameLayout>或<LinearLayout>

更新：

在MainActivity中使用android.app.FragmentTransaction;。但你的片段是android.support.v4.app.Fragment;。你不能这样做。您必须完全使用AppCompat_v4。请改用android.app.Fragment。

或者我强烈建议您MainActivity延长FragmentActivity并使用getSupportFragmentManager()代替getFragmentManager()。

Answer 2

在 main_activity_xml ：

中使用此功能

<FrameLayout
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:id="@+id/fragmentcontainer">
</FrameLayout>

比 MainActivity.java 更换当前片段（用YourFragment更改RecyclerTestActivity）：

Fragment fr;
FragmentManager fm = getFragmentManager();
FragmentTransaction fragmentTransaction = fm.beginTransaction();
fr = new YourFragment();
fragmentTransaction.replace(R.id.fragmentcontainer, fr);
fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
fragmentTransaction.commit();

记得导入：

import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;

YourFragment.java是一个扩展Fragment（android.app.Fragment）的类，请点击Fragment Docs

Fragment类示例（Google Docs示例）：

public static class ExampleFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.example_fragment, container, false);
    }
}

所以你的代码是：

<强> MainActivity.java

package com.example.recyclerviewtest;

import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.os.StrictMode;

public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    if(savedInstanceState == null)
    {
    Fragment fr;
    FragmentManager fm = getFragmentManager();
    FragmentTransaction fragmentTransaction = fm.beginTransaction();
    fr = new  RecyclerTestActivity();
    fragmentTransaction.replace(R.id.fragmentcontainer, fr);
    fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
    fragmentTransaction.commit();
    if (android.os.Build.VERSION.SDK_INT > 9) {
          StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
          StrictMode.setThreadPolicy(policy);
        }
}
}
}

<强> main_activity_layout.xml ：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="${relativePackage}.${activityClass}" 
android:orientation="horizontal">

    <FrameLayout
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:id="@+id/fragmentcontainer">
    </FrameLayout>
</LinearLayout>

您的 RecyclerTestActivity.java ：

package com.example.recyclerviewtest;

import java.util.ArrayList;
import java.util.List;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;


public class RecyclerTestActivity extends Fragment {
private Adapter adapter;
private RecyclerView recyclerview;
@Override
public View onCreateView(LayoutInflater inflater,
        @Nullable ViewGroup container, @Nullable Bundle savedInstanceState)     {
    View Layout = inflater.inflate(R.layout.activity_recycler_test,container,false);
    recyclerview=(RecyclerView)Layout.findViewById(R.id.drawer);
    adapter=new Adapter(getActivity(), getdata());
    recyclerview.setAdapter(adapter);
    recyclerview.setLayoutManager(new LinearLayoutManager(getActivity()));

    return Layout;
}

public List<Information> getdata()
{
    List<Information> items = new ArrayList<>();
    int[] data ={R.drawable.ic_launcher,R.drawable.ic_launcher,R.drawable.ic_launcher};
    String[] content={"One","Two","Three"};

    for(int i=0;i<data.length;i++)
    {
        Information current = new Information();
        current.desc=content[i];
        current.number=data[i];
        items.add(current);
    }

    return items;

}

}

Answer 3

一个Activity不是片段因此你不能将它用作片段..你需要创建一个片段来将它添加到你的FragmentManager中。请参阅here。

片段没有膨胀

3 个答案: