软件框架的搭建【Fragment】

       第一讲_软件框架的搭建

 

 1_启动页面(LauncherActivity)

1.1_启动页面的布局

<?xml version="1.0"encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:background="#ffffff">     <ImageView         android:id="@+id/iv_icon"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_centerInParent="true"         android:src="@drawable/atguigu_logo"/>     <TextView         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_below="@id/iv_icon"         android:layout_centerHorizontal="true"         android:text="尚硅谷Android世界..."         android:textSize="18sp"/> </RelativeLayout>

 

1.2_启动页面的代码

延迟两秒进入主页面

packagecom.atguigu.atguigu.activity; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.os.Handler; import com.atguigu.atguigu.R; /**  * 作用：启动页面  */ public class LauncherActivityextendsActivity {     @Override     protected voidonCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_launcher);         new Handler().postDelayed(newRunnable() {             @Override             public voidrun() {                 startMainActivity();             }         }, 2000);     }     /**      * 启动主页面      */     private voidstartMainActivity() {         Intent intent = new Intent(this,MainActivity.class);         startActivity(intent);         finish();     } }

 2_主页面

2.1_主页面实现的分析

2.2_主页面的布局

主页面采用的是线性布局，中间是FrameLayout并且设置权重1，底部是RadioGroup

 

<?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">     <!--标题栏-->     <includelayout="@layout/titlebar"/>     <!--FrameLayout-->     <FrameLayout         android:id="@+id/fl_content"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:layout_weight="1"/>     <!--RadioGroup-->     <RadioGroup         android:id="@+id/rg_bottom_tag"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:background="#11000000"         android:gravity="center_vertical"         android:orientation="horizontal"         android:padding="3dp"         >         <RadioButton             android:id="@+id/rb_common_frame"             android:text="常用框架"             android:drawableTop="@drawable/rb_common_frame_drawable_selector"             style="@style/botttom_tag_style"             />         <RadioButton             android:id="@+id/rb_thirdparty"             android:text="第三方"             android:drawableTop="@drawable/rb_thirdparty_drawable_selector"             style="@style/botttom_tag_style"             />         <RadioButton             android:id="@+id/rb_custom"             android:text="自定义控件"             android:drawableTop="@drawable/rb_custom_drawable_selector"             style="@style/botttom_tag_style"             />         <RadioButton             android:id="@+id/rb_other"             android:text="其他"             android:drawableTop="@drawable/rb_other_drawable_selector"             style="@style/botttom_tag_style"             />     </RadioGroup> </LinearLayout>

 

 

Titlebar标题栏

<?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="50dp"     android:background="@android:color/holo_blue_light"     android:gravity="center"     android:orientation="horizontal">     <TextView         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:clickable="true"         android:text="尚硅谷知识库"         android:textColor="#ffffff"         android:textSize="20sp" /> </LinearLayout>

 

 

在values/styles/botttom_tag_style 的代码

 

<stylename="botttom_tag_style">     <!-- Customize your theme here. -->     <itemname="android:layout_width">wrap_content</item>     <item name="android:layout_height">wrap_content</item>     <item name="android:layout_gravity">center_vertical</item>     <item name="android:button">@android:color/transparent</item>     <item name="android:drawablePadding">3dp</item>     <item name="android:gravity">center</item>     <item name="android:textColor">@drawable/rb_style_textcolor_selector</item>     <item name="android:textSize">10sp</item>     <item name="android:layout_weight">1</item> </style>

 

 

rb_style_textcolor_selector代码

 

颜色值一般是由设计师提供，不需要记住

<?xml version="1.0"encoding="utf-8"?> <selector xmlns:android="http://schemas.android.com/apk/res/android">     <item android:state_checked="false"android:color="#363636"/>     <item android:state_checked="true"android:color="#3097FD"/> </selector>

2.3_实例化布局控件

/**  * 初始化控件  */ private void initView() {     setContentView(R.layout.activity_main);     rg_bottom_tag = (RadioGroup) findViewById(R.id.rg_bottom_tag); }

 3_创建各个子页面

3.1_创建BaseFragment

packagecom.atguigu.atguigu.base; import android.content.Context; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v4.app.Fragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; /**  * 作用：基类Fragment  * CommonFrameFragment,ThirdParty,CustomFragment,OtherFragment等类继承它  */ public abstract class BaseFragment extends Fragment {     /**      * 上下文      */     protectedContextmContext;     /**      * 该Fragment是否被初始化过      */     private booleanisInit=false;     @Override     public voidonCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         mContext = getActivity();     }     @Nullable     @Override     publicView onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {         return initView();     }     /**      * 由子类实现该方法，创建自己的视图      *@return      */     protected abstractView initView() ;     @Override     public voidonActivityCreated(@NullableBundle savedInstanceState) {         super.onActivityCreated(savedInstanceState);         initData();     }     /**      * 子类，需要初始化数据，联网请求数据并且绑定数据，等重写该方法      */     protected voidinitData() {     } }

 

3.2_定义各个子页面

CommonFrameFragment 常用框架Fragment

 

/**  * 作用：常用框架  */ public class CommonFrameFragment extendsBaseFragment {     private static final StringTAG= CustomFragment.class.getSimpleName();     private TextView textView;     @Override     protectedView initView() {         Log.e(TAG,"常用框架页面初始化了...");         textView = new TextView(mContext);         textView.setGravity(Gravity.CENTER);         textView.setTextSize(20);         textView.setTextColor(Color.BLACK);         return textView;     }     @Override     protected voidinitData() {         super.initData();         Log.e(TAG,"常用框架数据初始化了...");         textView.setText("我是常用框架页面");     } }

 

 

 

CustomFragment 自定义Fragment类

 

/**  * 作用：自定义  */ public class CustomFragmentextendsBaseFragment {     private static final StringTAG= CustomFragment.class.getSimpleName();     private TextView textView;     @Override     protectedView initView() {         Log.e(TAG,"自定义页面初始化了...");         textView = new TextView(mContext);         textView.setGravity(Gravity.CENTER);         textView.setTextSize(20);         textView.setTextColor(Color.BLACK);         return textView;     }     @Override     protected voidinitData() {         super.initData();         Log.e(TAG,"自定义数据初始化了...");         textView.setText("我是自定义页面");     } }

 

 

ThirdPartyFragment 第三方Fragment

 

/**  * 作用：第三方  */ public class ThirdPartyFragmentextendsBaseFragment {     private static final StringTAG= ThirdPartyFragment.class.getSimpleName();     private TextView textView;     @Override     protectedView initView() {         Log.e(TAG,"第三方页面初始化了...");         textView = new TextView(mContext);         textView.setGravity(Gravity.CENTER);         textView.setTextSize(20);         textView.setTextColor(Color.BLACK);         return textView;     }     @Override     protected voidinitData() {         super.initData();         Log.e(TAG,"第三方数据初始化了...");         textView.setText("我是第三方页面");     } }

 

 

 

 

OtherFragment  其他Fragment

 

/**  * 作用：其他  */ public class OtherFragmentextendsBaseFragment {     private static final StringTAG= OtherFragment.class.getSimpleName();     private TextView textView;     @Override     protectedView initView() {         Log.e(TAG,"其他页面初始化了...");         textView = new TextView(mContext);         textView.setGravity(Gravity.CENTER);         textView.setTextSize(20);         textView.setTextColor(Color.BLACK);         return textView;     }     @Override     protected voidinitData() {         super.initData();         Log.e(TAG,"其他数据初始化了...");         textView.setText("我是其他页面");     } }

 

 

3.3_初始化Fragment

 

/**  * 初始化Fragment  */ private void initFragment() {     mBaseFragments = new ArrayList<>();     mBaseFragments.add(newCommonFrameFragment());//常用框架     mBaseFragments.add(newThirdPartyFragment());//第三方     mBaseFragments.add(newCustomFragment());//自定义     mBaseFragments.add(newOtherFragment());//其他 }

 

 

3.4_设置RadioGroup的监听

private voidsetListener() {     rg_bottom_tag.setOnCheckedChangeListener(newMyOnCheckedChangeListener());     //设置默认主页面     rg_bottom_tag.check(R.id.rb_common_frame); } class MyOnCheckedChangeListenerimplementsRadioGroup.OnCheckedChangeListener {     @Override     public voidonCheckedChanged(RadioGroup group,intcheckedId) {             switch (checkedId){             case R.id.rb_common_frame:                 position =0;                 break;             case R.id.rb_thirdparty:                 position =1;                 break;             case R.id.rb_custom:                 position =2;                 break;             case R.id.rb_other:                 position =3;                 break;             default:                 position =0;                 break;         }         Fragment  fragment = getFragment();         switchFragment(mContent, fragment);     } }

 

3.5_得到Fragment

/**  * 得到Fragment  * @return  */ private BaseFragment getFragment() {     if(mBaseFragments!=null){         BaseFragment baseFragment = mBaseFragments.get(position);         return baseFragment;     }     return null; }

 

3.6_切换Fragment

private voidswitchFrament(BaseFragment fragment) {     //1.得到FragmentManger     FragmentManager fm = getSupportFragmentManager();     //2.开启事务     FragmentTransaction transaction = fm.beginTransaction();     //3.替换     transaction.replace(R.id.fl_content,fragment);     //4.提交事务     transaction.commit(); }

 4_软件框架性能优化

4.1_解决切换Fragment切换导致重新创建Fragment问题

在项目中切换Fragment，一直都是用replace()方法来替换Fragment。但是这样做有一个问题，每次切换的时候Fragment都会重新实列化，重新加载一次数据，这样做会非常消耗性能用用户的流量。

官方文档解释说：replace()这个方法只是在上一个Fragment不再需要时采用的简便方法。

正确的切换方式是add()，切换时hide()，add()另一个Fragment；再次切换时，只需hide()当前，show()另一个。
这样就能做到多个Fragment切换不重新实例化：

切换方法：

 

 

/**  * 切换不同的Fragment  * @paramfrom  *@paramto  */ public void switchFragment(Fragment from, Fragment to) {     if (mContent!= to) {         mContent = to;         FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();         if (!to.isAdded()) {           // 先判断是否被add过             if(from !=null){                 transaction.hide(from);             }             if(to != null){                 transaction.add(R.id.fl_content, to).commit();             }         } else {             if(from != null){                 transaction.hide(from);             }             if(to != null){                 transaction.show(to).commit();             }         }     } }

 

4.2_解决横竖屏切换导致的Fragment内容重叠问题

 

在功能清单文件配置

<activityandroid:name=".activity.MainActivity"     android:configChanges="orientation|keyboardHidden|screenSize"     > </activity>

 

 

 5_常用框架页面功能实现

5.1_常用框架页面布局fragment_common_frame.xml

<?xml version="1.0"encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent">     <ListView         android:id="@+id/listview"         android:layout_width="match_parent"         android:layout_height="match_parent"/> </RelativeLayout>

 

 

5.2_常用框架页面代码

/**  * 作用：常用框架  */ public class CommonFrameFragmentextendsBaseFragment {     private static final StringTAG= CommonFrameFragment.class.getSimpleName();     private ListView mListview;     private String [] datas;     private CommonFrameFragmentAdapteradapter;     @Override     protectedView initView() {         Log.e(TAG,"常用框架页面初始化了...");         View view = View.inflate(mContext, R.layout.fragment_common_frame,null);         mListview = (ListView) view.findViewById(R.id.listview);         mListview.setOnItemClickListener(newAdapterView.OnItemClickListener() {             @Override             public voidonItemClick(AdapterView<?> parent, View view,intposition,longid) {                 String data = datas[position];                 Toast.makeText(mContext,"data=="+data, Toast.LENGTH_SHORT).show();             }         });         return view;     }     @Override     protected voidinitData() {         super.initData();         Log.e(TAG,"常用框架数据初始化了...");         //准备数据         datas=newString[]{"OKHttp","xUtils3","Retrofit2","Fresco","Glide","greenDao","RxJava","volley","Gson","FastJson","picasso","evenBus","jcvideoplayer","pulltorefresh","Expandablelistview","UniversalVideoView","....."};         //设置适配器         adapter=newCommonFrameFragmentAdapter(mContext,datas);         mListview.setAdapter(adapter);     } }

 

 

5.3_常用框架页面适配器

重新创建一个新包，com.atguigu.android.adapter

 

/**  * 作用：常用框架的适配器  */ public class CommonFrameFragmentAdapterextendsBaseAdapter {     private final ContextmContext;     private final String[]mDatas;     public CommonFrameFragmentAdapter(Context context,String[] datas){         this.mContext= context;         this.mDatas= datas;     }     @Override     public intgetCount() {         return mDatas.length;     }     @Override     publicObject getItem(intposition) {         return null;     }     @Override     public longgetItemId(intposition) {         return 0;     }     @Override     publicView getView(intposition, View convertView, ViewGroup parent) {         TextView textView = new TextView(mContext);         textView.setPadding(10, 10, 0, 10);         textView.setText(mDatas[position]);         textView.setTextColor(Color.BLACK);         textView.setTextSize(20);         return textView;     } }