Android Fragment的使用 《第一行代码》

一.静态Fragment

1.定义Fragment的布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:background="#000000">

<TextView
android:textSize="20sp"
android:text="This is headlines fragment"
android:layout_gravity="center_horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>

2.创建对应布局文件的Fragment类

对与Fragment类的布局文件的加载需要使用动态加载LayoutInflater.inflater()

获取LayoutInflater实例的三种方式

1.LayoutInflater inflater = getLayoutInflater();在Activity中获取实例对象

2.LayoutInflater inflater = (LayoutInflater) context.getSystemService

(Context.LAYOUT_INFLATER_SERVICE);

3.LayoutInflater inflater = LayoutInflater.from(context);

public class HeadlinesFragment extends Fragment {

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

}

定义显示Fragment的Activity的布局文件

在布局文件中需要添加Fragment的位置添加

<fragment
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:name="定义的Fragment对应类"
android:id="@+id/article_fragment"/>

定义显示Activity的类

public class FragmentActivity extends Activity {

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

二.动态Fragment

1.定义需要动态添加的Fragment布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical"
android:background="#ffff00">

<TextView
android:text="This is another fragment"
android:textSize="20sp"
android:layout_gravity="center_horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>

2.定义需要动态添加的Fragment类

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

3.Activity的布局文件中添加Fragment容器

<FrameLayout
android:id="@+id/right_layout"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="match_parent">
<fragment
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.example.myfirst.myfirst.HeadlinesFragment"
android:id="@+id/headlines_fragment"/>
</FrameLayout>

4.获取FragmentManager

在活动中可以直接获取FragmentManager对象

FragmentManager fragmentManager = getFragmentManager();

5.开启一个事务，通过调用beginTransaction（）方法开启

FragmentTransaction transaction = fragmentManager
.beginTransaction();

6.调用替换的方法

传入的两个参数，第一个是放置Fragmnet的容器的id，第二个参数是新的Fragment对象的实例对象

transaction.replace(R.id.right_layout,fragment);

7.提交事务

transaction.commit();

所有代码

fragment_article.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<Button
android:id="@+id/button"
android:text="Button"
android:layout_gravity="center_horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>

ArticleFragment.java

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

fragment_headlines.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:background="#000000">

<TextView
android:textSize="20sp"
android:text="This is headlines fragment"
android:layout_gravity="center_horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>

HeadlinesFragment.java

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

another_fragment.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical"
android:background="#ffff00">

<TextView
android:text="This is another fragment"
android:textSize="20sp"
android:layout_gravity="center_horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>

anotherFragment.java

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

activity_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<fragment
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:name="com.example.myfirst.myfirst.ArticleFragment"
android:id="@+id/article_fragment"/>
<FrameLayout
android:id="@+id/right_layout"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="match_parent">
<fragment
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.example.myfirst.myfirst.HeadlinesFragment"
android:id="@+id/headlines_fragment"/>
</FrameLayout>

</LinearLayout>

FragmentActivity.java

public class FragmentActivity extends Activity implements View.OnClickListener{

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_fragment);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(this);
}

@Override
public void onClick(View v){
switch (v.getId()){
case R.id.button:
anotherFragment fragment = new anotherFragment();
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.right_layout,fragment);
//使按下back键可以返回到上一个碎片
transaction.addToBackStack(null);
transaction.commit();
break;
default:
break;
}
}
}

以上是对Fragment学习的记录。