Fragment基础复习

Android自3.0版本开始，为了适应平板的需要，引入了fragment。由于学习时间较长，几乎忘了怎么使用了。今天看了《第一行代码》中的例子，重新对着敲了一遍，在此记录，以便日后的不时之需。

通过xml文件的方式添加fragment。

先是fragment_left.xml

<pre name="code" class="html"><?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" >    <Button        android:id="@+id/btn"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center_horizontal"        android:text="显示" /></LinearLayout>

其次fragment_right.xml

<pre name="code" class="html"><?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"    android:background="#00ff00" >    <TextView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_gravity="center_horizontal"        android:text="This is right fragment."        android:textSize="20sp" /></LinearLayout>

再是LeftFragment.java

package com.dt.bitmapoptionsd.fragment;import android.app.Fragment;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import com.dt.bitmapoptionsd.R;public class LeftFragment extends Fragment {@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {return View.inflate(getActivity(), R.layout.fragment_left, null);}}

再是RightFragment.java

package com.dt.bitmapoptionsd.fragment;import android.app.Fragment;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import com.dt.bitmapoptionsd.R;public class RightFragment extends Fragment {@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {return View.inflate(getActivity(), R.layout.fragment_right, null);}}

再是fragment_layout.xml

<pre name="code" class="html"><?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" >    <fragment        android:id="@+id/left_fragment"        android:name="com.dt.bitmapoptionsd.fragment.LeftFragment"        android:layout_width="0dp"        android:layout_height="match_parent"        android:layout_weight="1" />             <fragment            android:id="@+id/right_fragment"            android:name="com.dt.bitmapoptionsd.fragment.RightFragment"android:layout_width="0dp"        android:layout_height="match_parent"        android:layout_weight="1"             /></LinearLayout>

最后是FragmentTest.java

public class FragmentTest extends Activity implements OnClickListener{private Button btn;private boolean isGreen = true;@Overrideprotected void onCreate(Bundle savedInstanceState) {requestWindowFeature(Window.FEATURE_NO_TITLE);super.onCreate(savedInstanceState);setContentView(R.layout.fragment_layout);}

通过代码的方式动态的替换fragment。

先修改一下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" >    <fragment        android:id="@+id/left_fragment"        android:name="com.dt.bitmapoptionsd.fragment.LeftFragment"        android:layout_width="0dp"        android:layout_height="match_parent"        android:layout_weight="1" />    <FrameLayout        android:id="@+id/right_layout"        android:layout_width="0dp"        android:layout_height="match_parent"        android:layout_weight="1" >        <fragment            android:id="@+id/right_fragment"            android:name="com.dt.bitmapoptionsd.fragment.RightFragment"            android:layout_width="match_parent"            android:layout_height="match_parent" />    </FrameLayout></LinearLayout>

再新建一个fragment_right_two.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"    android:background="#ffff00" >    <TextView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_gravity="center_horizontal"        android:text="This is right fragment."        android:textSize="20sp" /></LinearLayout>

对应的SecondRightFragment.java

package com.dt.bitmapoptionsd.fragment;import android.app.Fragment;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import com.dt.bitmapoptionsd.R;public class SecondRightFragment extends Fragment {@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {return inflater.inflate(R.layout.fragment_right_two, container, false);}}

最后的FragmentTest.java。其中为了当点击返回键的时候，实现像activity一样的退栈效果，而不是直接退出应用，调用了transaction的addToBackStack方法。

package com.dt.bitmapoptionsd.fragment;import android.app.Activity;import android.app.FragmentManager;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.view.Window;import android.widget.Button;import com.dt.bitmapoptionsd.R;public class FragmentTest extends Activity implements OnClickListener{private Button btn;private boolean isGreen = true;@Overrideprotected void onCreate(Bundle savedInstanceState) {requestWindowFeature(Window.FEATURE_NO_TITLE);super.onCreate(savedInstanceState);setContentView(R.layout.fragment_layout);btn = (Button) findViewById(R.id.btn);btn.setOnClickListener(this);}@Overridepublic void onClick(View v) {if(v.getId() == R.id.btn){FragmentManager manager = getFragmentManager();SecondRightFragment secondfragment = new SecondRightFragment();RightFragment fragment = new RightFragment();if(isGreen){manager.beginTransaction().replace(R.id.right_layout, secondfragment).addToBackStack(null).commit();}else{manager.beginTransaction().replace(R.id.right_layout, fragment).addToBackStack(null).commit();}isGreen = !isGreen;}}}