较低 API 上的 Android 片段 [英] Android Fragments on lower API

问题描述

好吧，我开始了解 Android Fragments 但这对我来说仍然令人困惑.我需要一点帮助.正如它所说，自 API 级别 11 起支持 android 片段，但您可以下载support.v4"库包用于较低级别的 API.好吧，首先我创建了一个新项目来尝试 API 级别 15 上的片段.然后我对 API 级别 8 做了同样的事情，但它不起作用......我导入了外部 jar，它看到了所有需要的导入......似乎是什么是这里的问题吗?

well I'm starting to understand Android Fragments but this is still confusing for me. I need a little help. As it says android fragments is supported since API level 11 but you can download "support.v4" libraries pack for lower level APIs. Well first I create new project to try fragments on API level 15. Then I did the same with API level 8 and it does not work... I imported external jar and it sees all needed import as it should... What seems to be the problem here?

这是我的主要课程:

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

public class Fragment2Activity extends FragmentActivity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }
}

我的主要布局 XML:

My main layout 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:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

        <fragment 
   android:name="com.frag.Fragment2.frag"
   android:id="@+id/frag"
   android:layout_width="match_parent"
   android:layout_height="match_parent" />

</LinearLayout>

我的片段类:

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

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

还有我的片段布局 XML:

And my fragment layout XML:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <TextView
   android:layout_width="fill_parent"
   android:layout_height="match_parent"
   android:text="THIS IS FRAGMENT"
   android:background="@drawable/ic_launcher"
/>

</LinearLayout>

已修复

推荐答案

您仍在使用 android.view.fragment 类，该类不存在.您必须在旧设备上切换到 android.support.v4.app.fragment.

You are still using the android.view.fragment class, which does not exist. You have to switch to android.support.v4.app.fragment on older devices.

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