扣丁学堂笔记第12天Fragments
1.Fragment简介
2.添加Fragment的两种方式
方式一：通过xml属性配置
新建一个TitleFragment、一个ContentFragment均继承自Fragment，然后在布局文件中设置fragment属性（要有id，name）；
新建两个xml，分别用来作为两个Fragment的视图，然后再Fragment中重写onCreateView()方法加载布局，返回的是view对象
activity_main.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"
android:orientation="horizontal"
tools:context="com.example.fragmenttest.MainActivity" >
<fragment
android:id="@+id/title_fragment"
android:name="com.example.fragmenttest.TitleFragment"
android:layout_width="0dip"
android:layout_height="match_parent"
android:layout_weight="1" />
<fragment
android:id="@+id/content_fragment"
android:name="com.example.fragmenttest.ContentFragment"
android:layout_width="0dip"
android:layout_height="match_parent"
android:layout_weight="3" />
</LinearLayout>
title_layout
<?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">
<Button
android:id="@+id/btn_1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="时间" />
<Button
android:id="@+id/btn_2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="地点"/>
<Button
android:id="@+id/btn_3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="人物"/>
</LinearLayout>
content_layout
<?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:background="#00ddff"
android:orientation="vertical" >
<TextView
android:id="@+id/content_tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="not data" />
</LinearLayout>
TitleFragment.java'
package com.example.fragmenttest;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class TitleFragment extends Fragment{
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.title_layout, container, false);
return view;
}
}
ContetFragment
package com.example.fragmenttest;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class ContentFragment extends Fragment{
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.content_layout, container, false);
return view;
}
}
方式二：通过代码添加Fragment（以contentFragment为例）
把content_layout.xml的<fragment/>改为<FragmentLayout></FragmentLayout>，并且删去android:name=""属性，
MainActivity.java
package com.example.fragmenttest;
import android.app.Activity;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
public class MainActivity extends Activity {
// TitleFragment titleFragment;
ContentFragment contentFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addTitleLayout();
}
/*
* 通过代码加载contentFragment
*/
private void addTitleLayout() {
// 1.获取一个Fragment管理器
FragmentManager fm = getFragmentManager();
// 2.开启一个Fragment事务
FragmentTransaction ft = fm.beginTransaction();
// 3.实例化Fragment对象
contentFragment = new ContentFragment();
// 4.添加fragment
ft.add(R.id.content_layout, contentFragment);
// ft.remove();删除
// ft.replace();替换
// 5.提交事务
ft.commit();
}
}
activity_main
<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="horizontal"
tools:context="com.example.fragmenttest.MainActivity" >
<fragment
android:id="@+id/title_fragment"
android:name="com.example.fragmenttest.TitleFragment"
android:layout_width="0dip"
android:layout_height="match_parent"
android:layout_weight="1" />
<FrameLayout
android:id="@+id/content_layout"
android:layout_width="0dip"
android:layout_height="match_parent"
android:layout_weight="3" ></FrameLayout>
</LinearLayout>
3.Fragment出入栈操作
MainActivity
package com.example.fragmenttest2;
import android.app.Activity;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
//
public void oneClick(View view) {
MyFragment fragment1 = new MyFragment("one");
FragmentTransaction ft1 = getFragmentManager().beginTransaction();
ft1.replace(R.id.content_layout, fragment1);
// 把ft1添加到返回栈
ft1.addToBackStack(null);
ft1.commit();
}
public void twoClick(View view) {
MyFragment fragment1 = new MyFragment("two");
FragmentTransaction ft1 = getFragmentManager().beginTransaction();
ft1.replace(R.id.content_layout, fragment1);
// 把ft1添加到返回栈
ft1.addToBackStack(null);
ft1.commit();
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
if (getFragmentManager().getBackStackEntryCount() == 0) {
finish();
} else {
getFragmentManager().popBackStack();// 出栈
}
return true;
}
return super.onKeyDown(keyCode, event);
}
}
activity_main
<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"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.fragmenttest2.MainActivity" >
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="one"
android:onClick="oneClick"/>
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/button1"
android:layout_alignParentRight="true"
android:text="two"
android:onClick="twoClick" />
<FrameLayout
android:id="@+id/content_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignLeft="@+id/button1"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_below="@+id/button1" >
</FrameLayout>
</RelativeLayout>
MyFragment
package com.example.fragmenttest2;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class MyFragment extends Fragment {
// public static MyFragment getInstance(String title){
// Bundle b = new Bundle();
// b.putString("title", title);
// MyFragment myFragment = new MyFragment();
// myFragment.setArguments(b);
// return myFragment;
//
// }
//
// @Override
// public View onCreateView(LayoutInflater inflater, ViewGroup container,
// Bundle savedInstanceState) {
// View view = inflater.inflate(R.id.content_framelayout, container, false);
// TextView textView = (TextView) view.findViewById(R.id.textView1);
// textView.setText(getArguments().getString("title"));
// return view;
// }
private String title;
public MyFragment() {
}
public MyFragment(String title) {
this.title = title;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.content_framelayout, container,
false);
TextView textView = (TextView) view.findViewById(R.id.textView1);
textView.setText(title);
return view;
}
}
content_framelayout
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="@+id/textView1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:text="hello blank fragment" />
</FrameLayout>
4.Fragment传参方式
上述逻辑代码存在缺陷，即在旋转屏幕之后，原来的数据会丢失，说明重新创建了Activity
MyFragmenr
package com.example.fragmenttest2;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class MyFragment extends Fragment {
/*
* Fragment的传参方法
*/
//通过构造一个getInstance方法传递参数
public static MyFragment getInstance(String title){
Bundle b = new Bundle();
b.putString("title", title);
MyFragment myFragment = new MyFragment();
myFragment.setArguments(b);
return myFragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.content_framelayout, container, false);
TextView textView = (TextView) view.findViewById(R.id.textView1);
textView.setText(getArguments().getString("title"));
return view;
}
// private String title;
//
// public MyFragment() {
// }
//
// public MyFragment(String title) {
// this.title = title;
// }
//
// @Override
// public View onCreateView(LayoutInflater inflater, ViewGroup container,
// Bundle savedInstanceState) {
// View view = inflater.inflate(R.layout.content_framelayout, container,
// false);
// TextView textView = (TextView) view.findViewById(R.id.textView1);
// textView.setText(title);
// return view;
// }
}
MainActivity
package com.example.fragmenttest2;
import android.app.Activity;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void oneClick(View view) {
// MyFragment fragment1 = new MyFragment("one");
MyFragment fragment1 = MyFragment.getInstance("one");
FragmentTransaction ft1 = getFragmentManager().beginTransaction();
ft1.replace(R.id.content_layout, fragment1);
// 把ft1添加到返回栈
ft1.addToBackStack(null);
ft1.commit();
}
public void twoClick(View view) {
// MyFragment fragment1 = new MyFragment("two");
MyFragment fragment1 = MyFragment.getInstance("two");
FragmentTransaction ft1 = getFragmentManager().beginTransaction();
ft1.replace(R.id.content_layout, fragment1);
// 把ft1添加到返回栈
ft1.addToBackStack(null);
ft1.commit();
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
if (getFragmentManager().getBackStackEntryCount() == 0) {
finish();
} else {
getFragmentManager().popBackStack();// 出栈
}
return true;
}
return super.onKeyDown(keyCode, event);
}
}
5.Fragment与Activity交互
MainActivity
package com.example.fragmenttest3;
import com.example.fragmenttest3.MyMenuFragment.MyMenuListener;
import android.app.Activity;
import android.os.Bundle;
//宿主要实现定义的回调接口
public class MainActivity extends Activity implements MyMenuListener {
private MyMenuFragment menuFragment;
private MyInfoFragment infoFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
menuFragment = (MyMenuFragment) getFragmentManager().findFragmentById(
R.id.menuFragment);
infoFragment = (MyInfoFragment) getFragmentManager().findFragmentById(
R.id.infoFragment);
}
@Override
public void changeValue(String value) {
// TODO Auto-generated method stub
infoFragment.changeTextViewValue(value);
}
}
activity_main
<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="com.example.fragmenttest3.MainActivity" >
<fragment
android:id="@+id/menuFragment"
android:name="com.example.fragmenttest3.MyMenuFragment"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1" />
<fragment
android:id="@+id/infoFragment"
android:name="com.example.fragmenttest3.MyInfoFragment"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="2" />
</LinearLayout>
MyMenuFragment
package com.example.fragmenttest3;
import android.app.Activity;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.TextView;
public class MyMenuFragment extends Fragment implements OnClickListener{
private MyMenuListener menuListener;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.menu_fragmentlayout, container,false);
view.findViewById(R.id.btn_news).setOnClickListener(this);
view.findViewById(R.id.btn_music).setOnClickListener(this);
return view;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
//此时的menuListener代表的就是宿主Activity
menuListener = (MyMenuListener) activity;
}
// //点击事件要触发，就要先调用需要的接口，所以要事先声明一个接口 (和视频一样，用xml里on
click方法报错，所以改用setOnClickListener方法)
// public void newsClick(View v){
// menuListener.changeValue("news");
// }
//
// public void musicClick(View v){
// menuListener.changeValue("music");
// }
//哪里要产生事件(这里有两个按钮触发点击事件)，就在那里定义一个回调接口
public static interface MyMenuListener{
public void changeValue(String value);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch(v.getId()){
case R.id.btn_news:
menuListener.changeValue("news");
break;
case R.id.btn_music:
menuListener.changeValue("music");
break;
}
}
}
MyInfoFragment
package com.example.fragmenttest3;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class MyInfoFragment extends Fragment{
private TextView textView;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.info_fragmentlayout, container,false);
textView = (TextView) view.findViewById(R.id.tv);
return view;
}
public void changeTextViewValue(String value){
textView.setText(value);
}
}
menu_fragmentlayout
<?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_news"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="News"
/>
<Button
android:id="@+id/btn_music"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Music"
/>
</LinearLayout>
info_fragmentlayout
<?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:id="@+id/tv"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:text="Hello"/>
</LinearLayout>
6.PreferenceFragment
