活动里面添加一个碎片

fragment的布局文件fragment_demo.xml

<?xml version="1.0" encoding="utf-8"?>
<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"
android:orientation="vertical"
android:paddingBottom="0dp"
android:paddingLeft="@dimen/ijk_horizontal_margin"
android:paddingRight="@dimen/ijk_horizontal_margin"
android:paddingTop="0dp">

<EditText
android:layout_width="match_parent"
android:layout_height="100dp"
android:id="@+id/play_url"/>

</LinearLayout>

Activity里面的布局文件
<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"
android:orientation="vertical"
tools:context=".activities.FileExplorerActivity">

<include layout="@layout/widget_toolbar" />

<FrameLayout
android:id="@+id/body"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
把碎片添加到活动中去：
private void loadFragment() {
Log.d(TAG, "load DemoFragment");
Fragment newFragment = (Fragment)DemoFragment.newInstance();
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
//把fragment的布局贴到App_Activity的frameLayout控件上
transaction.replace(R.id.body, newFragment);
transaction.commit();
}

这么简单就搞定。