android中fragment實現

轉載：http://blog.csdn.net/crazy1235/article/details/50933621

Fragment

還是先來基本介紹。

Fragment –> 片段。
在Android3.0的時候被引入，它的出現主要是給大屏幕設備提供更加靈活的UI支持。通過對Activity佈局進行分片，更加方便的對每塊進行獨立控制。這些片段可以被不同的activity複用。

fragment生命週期

每個fragment擁有自己的生命週期，但是fragment要依賴於activity存在，生命週期受到包括它的activity的生命週期控制。

來兩張神圖~~

左圖就是fragment的生命週期圖。右圖是fragment與activity各自生命週期的對照。

介紹一下常用的幾個生命週期函數：

onAttach(Context) –> 當fragment被綁定到activity上時回調
onCreate(Bundle) –> 當fragment對象創建的時候回調，一般在此方法裏做參數接收。
onCreateView(LayoutInflater, ViewGroup, Bundle) –> 創建fragment視圖時回調
onDestoryView –> 視圖銷燬時回調
onDestory –> 銷燬fragment時回調
onDetech() –> fragment與activity失去關聯時回調

fragment的使用

使用fragment可以當成一個控件，直接放到activity佈局文件裏；也可以在代碼裏面動態的添加、更新或者刪除。

下面的activity佈局文件中定義了一個fragment和一個frameLayout。使用標籤可以稱之爲靜態的Fragment，在activity創建的時候也會去創建並顯示它，而framelayout是一個容器，我們在代碼中可以動態的添加一個fragment進去。

<code class="hljs xml has-numbering"><span class="hljs-pi"><?xml version="1.0" encoding="utf-8"?></span>
<span class="hljs-tag"><<span class="hljs-title">LinearLayout</span> <span class="hljs-attribute">xmlns:android</span>=<span class="hljs-value">"http://schemas.android.com/apk/res/android"</span>
    <span class="hljs-attribute">xmlns:tools</span>=<span class="hljs-value">"http://schemas.android.com/tools"</span>
    <span class="hljs-attribute">android:layout_width</span>=<span class="hljs-value">"match_parent"</span>
    <span class="hljs-attribute">android:layout_height</span>=<span class="hljs-value">"match_parent"</span>
    <span class="hljs-attribute">android:orientation</span>=<span class="hljs-value">"horizontal"</span>
    <span class="hljs-attribute">tools:context</span>=<span class="hljs-value">".fragments.ArticleActivity"</span>></span>
    <span class="hljs-comment"><!--headlines--></span>
    <span class="hljs-tag"><<span class="hljs-title">fragment
</span>        <span class="hljs-attribute">android:id</span>=<span class="hljs-value">"@+id/headline_fragment"</span>
        <span class="hljs-attribute">android:name</span>=<span class="hljs-value">"com.jacksen.demo.view.fragments.HeadlinesFragment"</span>
        <span class="hljs-attribute">android:layout_width</span>=<span class="hljs-value">"0dp"</span>
        <span class="hljs-attribute">android:layout_height</span>=<span class="hljs-value">"match_parent"</span>
        <span class="hljs-attribute">android:layout_weight</span>=<span class="hljs-value">"1"</span>
        <span class="hljs-attribute">tools:layout</span>=<span class="hljs-value">"@layout/fragment_item_list"</span> /></span>
    <span class="hljs-comment"><!--article--></span>
    <span class="hljs-tag"><<span class="hljs-title">FrameLayout
</span>        <span class="hljs-attribute">android:id</span>=<span class="hljs-value">"@+id/article_frame_layout"</span>
        <span class="hljs-attribute">android:layout_width</span>=<span class="hljs-value">"0dp"</span>
        <span class="hljs-attribute">android:layout_height</span>=<span class="hljs-value">"match_parent"</span>
        <span class="hljs-attribute">android:layout_weight</span>=<span class="hljs-value">"2"</span> /></span>
<span class="hljs-tag"></<span class="hljs-title">LinearLayout</span>></span></code>

注意：

使用標籤顯示Fragment的時候，需要對這個fragment設置一個id或者tag，否則會出現”Error inflating class fragment”錯誤。

<code class="hljs lasso has-numbering">Caused <span class="hljs-keyword">by</span>: java<span class="hljs-built_in">.</span>lang<span class="hljs-built_in">.</span>IllegalArgumentException: Binary <span class="hljs-built_in">XML</span> file line <span class="hljs-variable">#10</span>: Must specify unique android:id, android:<span class="hljs-built_in">tag</span>, <span class="hljs-literal">or</span> have a <span class="hljs-keyword">parent</span> <span class="hljs-keyword">with</span> an id for com<span class="hljs-built_in">.</span>jacksen<span class="hljs-built_in">.</span>demo<span class="hljs-built_in">.</span>view<span class="hljs-built_in">.</span>fragments<span class="hljs-built_in">.</span>HeadlinesFragment</code><ul class="pre-numbering" style="display: block;"><li>1</li></ul>

Fragment的子類繼承的時候，如果你的minSdkVersion <= 11，需要引入V4包，然後倒入android.support.v4.app.Fragment包。如果是大於11，直接導入android.app.Fragment包即可。

<code class="hljs java has-numbering"><span class="hljs-keyword">package</span> com.jacksen.demo.view.fragments;
<span class="hljs-keyword">import</span> android.content.Context;
<span class="hljs-keyword">import</span> android.os.Bundle;
<span class="hljs-keyword">import</span> android.support.v4.app.Fragment;
<span class="hljs-keyword">import</span> android.support.v7.widget.GridLayoutManager;
<span class="hljs-keyword">import</span> android.support.v7.widget.LinearLayoutManager;
<span class="hljs-keyword">import</span> android.support.v7.widget.RecyclerView;
<span class="hljs-keyword">import</span> android.util.Log;
<span class="hljs-keyword">import</span> android.view.LayoutInflater;
<span class="hljs-keyword">import</span> android.view.View;
<span class="hljs-keyword">import</span> android.view.ViewGroup;
<span class="hljs-keyword">import</span> com.jacksen.demo.view.R;
<span class="hljs-keyword">import</span> com.jacksen.demo.view.fragments.dummy.ArticleBean;
<span class="hljs-keyword">import</span> com.jacksen.demo.view.fragments.dummy.ArticleBean.ArticleItem;

<span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">HeadlinesFragment</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Fragment</span> {</span>
    <span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">final</span> String ARG_COLUMN_COUNT = <span class="hljs-string">"column-count"</span>;
    <span class="hljs-keyword">private</span> <span class="hljs-keyword">int</span> mColumnCount = <span class="hljs-number">2</span>;
    <span class="hljs-keyword">private</span> OnChangeArticleListener mListener;

    <span class="hljs-keyword">public</span> <span class="hljs-title">HeadlinesFragment</span>() {
    }
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> HeadlinesFragment <span class="hljs-title">newInstance</span>(<span class="hljs-keyword">int</span> columnCount) {
        HeadlinesFragment fragment = <span class="hljs-keyword">new</span> HeadlinesFragment();
        Bundle args = <span class="hljs-keyword">new</span> Bundle();
        args.putInt(ARG_COLUMN_COUNT, columnCount);
        fragment.setArguments(args);
        <span class="hljs-keyword">return</span> fragment;
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onAttach</span>(Context context) {
        <span class="hljs-keyword">super</span>.onAttach(context);
        Log.d(<span class="hljs-string">"HeadlinesFragment"</span>, <span class="hljs-string">"onAttach"</span>);
        <span class="hljs-keyword">if</span> (context <span class="hljs-keyword">instanceof</span> OnChangeArticleListener) {
            mListener = (OnChangeArticleListener) context;
        } <span class="hljs-keyword">else</span> {
            <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> RuntimeException(context.toString()
                    + <span class="hljs-string">" must implement OnChangeArticleListener"</span>);
        }
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onCreate</span>(Bundle savedInstanceState) {
        <span class="hljs-keyword">super</span>.onCreate(savedInstanceState);
        Log.d(<span class="hljs-string">"HeadlinesFragment"</span>, <span class="hljs-string">"onCreate"</span>);
        <span class="hljs-keyword">if</span> (getArguments() != <span class="hljs-keyword">null</span>) {
            mColumnCount = getArguments().getInt(ARG_COLUMN_COUNT);
        }
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> View <span class="hljs-title">onCreateView</span>(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        Log.d(<span class="hljs-string">"HeadlinesFragment"</span>, <span class="hljs-string">"onCreateView"</span>);
        View view = inflater.inflate(R.layout.fragment_item_list, container, <span class="hljs-keyword">false</span>);
        <span class="hljs-comment">// Set the adapter</span>
        <span class="hljs-keyword">if</span> (view <span class="hljs-keyword">instanceof</span> RecyclerView) {
            Context context = view.getContext();
            RecyclerView recyclerView = (RecyclerView) view;
            <span class="hljs-keyword">if</span> (mColumnCount <= <span class="hljs-number">1</span>) {
                recyclerView.setLayoutManager(<span class="hljs-keyword">new</span> LinearLayoutManager(context));
            } <span class="hljs-keyword">else</span> {
                recyclerView.setLayoutManager(<span class="hljs-keyword">new</span> GridLayoutManager(context, mColumnCount));
            }
            recyclerView.setAdapter(<span class="hljs-keyword">new</span> HeadlinesRecyclerViewAdapter(ArticleBean.ITEMS, mListener));
        }
        <span class="hljs-keyword">return</span> view;
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onDetach</span>() {
        <span class="hljs-keyword">super</span>.onDetach();
        Log.d(<span class="hljs-string">"HeadlinesFragment"</span>, <span class="hljs-string">"onDetach"</span>);
        mListener = <span class="hljs-keyword">null</span>;
    }
    <span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">interface</span> <span class="hljs-title">OnChangeArticleListener</span> {</span>
        <span class="hljs-keyword">void</span> onChangeArticle(ArticleItem item);
    }
}</code>

動態的添加fragment就需要在代碼裏面通過FragmentManager等類進行操作：

<code class="hljs avrasm has-numbering">frameLayout = (FrameLayout) findViewById(R<span class="hljs-preprocessor">.id</span><span class="hljs-preprocessor">.article</span>_frame_layout)<span class="hljs-comment">;</span>
fragmentManager = getSupportFragmentManager()<span class="hljs-comment">;</span>
articleFragment = ArticleFragment<span class="hljs-preprocessor">.newInstance</span>()<span class="hljs-comment">;</span>
fragmentManager<span class="hljs-preprocessor">.beginTransaction</span>()<span class="hljs-preprocessor">.replace</span>(R<span class="hljs-preprocessor">.id</span><span class="hljs-preprocessor">.article</span>_frame_layout, articleFragment)<span class="hljs-preprocessor">.commit</span>()<span class="hljs-comment">;</span></code>

Fragment的事務管理

android裏通過FragmentManager類進行管理fragment，一組對fragment的操作（添加、刪除、替換等）稱爲一個事務，通過FragmentTransaction類來提交執行。也可以把事務添加到回退棧中，進行回滾。這有點類似於數據庫的事務機制。

注意：

事物操作最後必須調用commit()才能執行。
調用commit()方法之後，也不是立刻執行；如果需要立刻執行，可以使用executePendingTransactions()方法。
一次性add多個fragment，顯示的是最後一個。
任務棧回退針對的是事務，而不是fragment。一次事務操作過程中可以有很多個對fragment的操作。
只能在activity處於可保存狀態的情況下，進行事務操作。否則引發如下異常：

<code class="hljs erlang has-numbering">java.lang.<span class="hljs-variable">IllegalStateException</span>: <span class="hljs-variable">Can</span> <span class="hljs-keyword">not</span> perform this action <span class="hljs-keyword">after</span> on<span class="hljs-variable">SaveInstanceState</span></code>

比如，在onPause()或者onStop()中提交事務，就會出現以上問題，如果非要在這些生命週期裏面進行事務提交，請使用FragmentTransaction類的commitAllowingStateLoss()方法，允許狀態丟失。

如果activity繼承的是AppCompatActivity，onBackPressed()回調函數裏面是利用的V4包的getSupportFragmentManager()進行的棧回退，所以做fragment回退的時候需要注意引用的是不是V4包的Fragment類。

<code class="hljs java has-numbering"><span class="hljs-javadoc">/**
     * Take care of popping the fragment back stack or finishing the activity
     * as appropriate.
     */</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onBackPressed</span>() {
        <span class="hljs-keyword">if</span> (!mFragments.getSupportFragmentManager().popBackStackImmediate()) {
            supportFinishAfterTransition();
        }
    }</code>

Fragment之間的切換

Fragment的切換就是基本就是利用add()、hide()、show()、replace()這四個方法。

情況一：採用add方式切換fragment

activity：

<code class="hljs avrasm has-numbering">@Override
    protected void onCreate(Bundle savedInstanceState) {
        super<span class="hljs-preprocessor">.onCreate</span>(savedInstanceState)<span class="hljs-comment">;</span>
        setContentView(R<span class="hljs-preprocessor">.layout</span><span class="hljs-preprocessor">.activity</span>_test_fragments2)<span class="hljs-comment">;</span>
        ButterKnife<span class="hljs-preprocessor">.bind</span>(this)<span class="hljs-comment">;</span>
        FragmentManager fragmentManager = getSupportFragmentManager()<span class="hljs-comment">;</span>
        TabFragment1 tabFragment1 = TabFragment1<span class="hljs-preprocessor">.newInstance</span>()<span class="hljs-comment">;</span>
        fragmentManager<span class="hljs-preprocessor">.beginTransaction</span>()<span class="hljs-preprocessor">.add</span>(R<span class="hljs-preprocessor">.id</span><span class="hljs-preprocessor">.test</span>_fragments_layout, tabFragment1)<span class="hljs-preprocessor">.addToBackStack</span>(<span class="hljs-string">"tab1"</span>)<span class="hljs-preprocessor">.commit</span>()<span class="hljs-comment">;</span>
    }</code>

TabFragment1代碼：

<code class="hljs java has-numbering"><span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> View <span class="hljs-title">onCreateView</span>(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        Log.d(<span class="hljs-string">"TabFragment1"</span>, <span class="hljs-string">"onCreateView"</span>);
        View view = inflater.inflate(R.layout.fragment_tab_fragment1, container, <span class="hljs-keyword">false</span>);
        ButterKnife.bind(<span class="hljs-keyword">this</span>, view);
        openNextBtn.setOnClickListener(<span class="hljs-keyword">new</span> View.OnClickListener() {
            <span class="hljs-annotation">@Override</span>
            <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onClick</span>(View v) {
                FragmentManager fragmentManager = getFragmentManager();
                TabFragment2 tabFragment2 = TabFragment2.newInstance();
                fragmentManager.beginTransaction().add(R.id.test_fragments_layout, tabFragment2).addToBackStack(<span class="hljs-keyword">null</span>).commit();
            }
        });
        <span class="hljs-keyword">return</span> view;
    }</code>

TabFragment2代碼：

<code class="hljs java has-numbering"><span class="hljs-javadoc">/**
 * Tab Fragment 2
 */</span>
<span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">TabFragment2</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">Fragment</span> {</span>
    <span class="hljs-keyword">public</span> <span class="hljs-title">TabFragment2</span>() {
    }
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> TabFragment2 <span class="hljs-title">newInstance</span>() {
        TabFragment2 fragment = <span class="hljs-keyword">new</span> TabFragment2();
        <span class="hljs-keyword">return</span> fragment;
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onAttach</span>(Context context) {
        <span class="hljs-keyword">super</span>.onAttach(context);
        Log.d(<span class="hljs-string">"TabFragment2"</span>, <span class="hljs-string">"onAttach"</span>);
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onCreate</span>(Bundle savedInstanceState) {
        <span class="hljs-keyword">super</span>.onCreate(savedInstanceState);
        Log.d(<span class="hljs-string">"TabFragment2"</span>, <span class="hljs-string">"onCreate"</span>);
        <span class="hljs-keyword">if</span> (getArguments() != <span class="hljs-keyword">null</span>) {
        }
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> View <span class="hljs-title">onCreateView</span>(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        Log.d(<span class="hljs-string">"TabFragment2"</span>, <span class="hljs-string">"onCreateView"</span>);
        <span class="hljs-keyword">return</span> inflater.inflate(R.layout.fragment_tab_fragment2, container, <span class="hljs-keyword">false</span>);
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onDestroyView</span>() {
        <span class="hljs-keyword">super</span>.onDestroyView();
        Log.d(<span class="hljs-string">"TabFragment2"</span>, <span class="hljs-string">"onDestroyView"</span>);
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onDestroy</span>() {
        <span class="hljs-keyword">super</span>.onDestroy();
        Log.d(<span class="hljs-string">"TabFragment2"</span>, <span class="hljs-string">"onDestroy"</span>);
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onDetach</span>() {
        <span class="hljs-keyword">super</span>.onDetach();
        Log.d(<span class="hljs-string">"TabFragment2"</span>, <span class="hljs-string">"onDetach"</span>);
    }
}</code>

此時都是採用add的方式進行顯示fragment。每次都會把添加fragment的事務疊加到回退棧上面。

在TabFragment1界面點擊按鈕添加TabFragment2界面，然後在按返回鍵回退，打印出生命週期如下：

情況二：採用replace的方式切換fragment

activity代碼不變。

TabFragment1的代碼如下：

<code class="hljs java has-numbering"><span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> View <span class="hljs-title">onCreateView</span>(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        Log.d(<span class="hljs-string">"TabFragment1"</span>, <span class="hljs-string">"onCreateView"</span>);
        View view = inflater.inflate(R.layout.fragment_tab_fragment1, container, <span class="hljs-keyword">false</span>);
        ButterKnife.bind(<span class="hljs-keyword">this</span>, view);
        openNextBtn.setOnClickListener(<span class="hljs-keyword">new</span> View.OnClickListener() {
            <span class="hljs-annotation">@Override</span>
            <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onClick</span>(View v) {
                FragmentManager fragmentManager = getFragmentManager();
                TabFragment2 tabFragment2 = TabFragment2.newInstance();
                fragmentManager.beginTransaction().replace(R.id.test_fragments_layout, tabFragment2).addToBackStack(<span class="hljs-keyword">null</span>).commit();
            }
        });
        <span class="hljs-keyword">return</span> view;
    }</code>

TabFragment1切換到TabFragment2的時候，使用的replace方法。replace方法的作用是remove掉所有添加到相同id的容器裏的fragment，然後添加參數裏的fragment。所以會回調TabFragment1的onDestoryView()方法，等到從TabFragment2返回的時候，去執行replace事務的相反操作，也就會重新創建TabFragment1的視圖，回調onCreateView()方法。

remove：

我們在TabFragment2界面中調用remove方法，把TabFragment1移除掉。

TabFragment1.java:

<code class="hljs java has-numbering"><span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> View <span class="hljs-title">onCreateView</span>(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        Log.d(<span class="hljs-string">"TabFragment1"</span>, <span class="hljs-string">"onCreateView"</span>);
        View view = inflater.inflate(R.layout.fragment_tab_fragment1, container, <span class="hljs-keyword">false</span>);
        ButterKnife.bind(<span class="hljs-keyword">this</span>, view);
        openNextBtn.setOnClickListener(<span class="hljs-keyword">new</span> View.OnClickListener() {
            <span class="hljs-annotation">@Override</span>
            <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onClick</span>(View v) {
                FragmentManager fragmentManager = getFragmentManager();
                TabFragment2 tabFragment2 = TabFragment2.newInstance();
                fragmentManager.beginTransaction().add(R.id.test_fragments_layout, tabFragment2).addToBackStack(<span class="hljs-keyword">null</span>).commit();
            }
        });
        <span class="hljs-keyword">return</span> view;
    }</code>

TabFragment2.java:

<code class="hljs java has-numbering"><span class="hljs-keyword">private</span> onBtnClickListener onBtnClickListener;
    <span class="hljs-keyword">public</span> <span class="hljs-title">TabFragment2</span>() {
    }
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> TabFragment2 <span class="hljs-title">newInstance</span>() {
        TabFragment2 fragment = <span class="hljs-keyword">new</span> TabFragment2();
        <span class="hljs-keyword">return</span> fragment;
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onAttach</span>(Context context) {
        <span class="hljs-keyword">super</span>.onAttach(context);
        Log.d(<span class="hljs-string">"TabFragment2"</span>, <span class="hljs-string">"onAttach"</span>);
        <span class="hljs-keyword">if</span> (context <span class="hljs-keyword">instanceof</span> onBtnClickListener){
            onBtnClickListener = (TabFragment2.onBtnClickListener) context;
        }<span class="hljs-keyword">else</span>{
            <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> RuntimeException(context.toString()
                    + <span class="hljs-string">" must implement onBtnClickListener"</span>);
        }
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onCreate</span>(Bundle savedInstanceState) {
        <span class="hljs-keyword">super</span>.onCreate(savedInstanceState);
        Log.d(<span class="hljs-string">"TabFragment2"</span>, <span class="hljs-string">"onCreate"</span>);
        <span class="hljs-keyword">if</span> (getArguments() != <span class="hljs-keyword">null</span>) {
        }
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> View <span class="hljs-title">onCreateView</span>(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        Log.d(<span class="hljs-string">"TabFragment2"</span>, <span class="hljs-string">"onCreateView"</span>);
        View view = inflater.inflate(R.layout.fragment_tab_fragment2, container, <span class="hljs-keyword">false</span>);
        ButterKnife.bind(<span class="hljs-keyword">this</span>, view);
        removeFragmentBtn.setOnClickListener(<span class="hljs-keyword">new</span> View.OnClickListener() {
            <span class="hljs-annotation">@Override</span>
            <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onClick</span>(View v) {
                onBtnClickListener.removeFragment1();
            }
        });
        <span class="hljs-keyword">return</span> view;
    }
    <span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">interface</span> <span class="hljs-title">onBtnClickListener</span>{</span>
        <span class="hljs-keyword">void</span> removeFragment1();
    }</code>

activity:

<code class="hljs java has-numbering"> <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">removeFragment1</span>() {
        fragmentManager.beginTransaction().remove(tabFragment1).commit();
    }</code>

從代碼裏看到，remove操作的事務沒有添加到回退棧中，所以從TabFragment2中返回的時候，直接退到了activity界面。

但是從界面來看，從TabFragment2會退到activity之後，再次按返回鍵並沒有退出activity，然後再按返回鍵的時候纔會退出activity。原因就是，雖然remove了TabFragment1，但是隻是回調了onDestoryView()方法銷燬了視圖，此時TabFragment1的對象資源和與activity的關聯還沒有斷開。所以點擊返回鍵的時候會有一個沒有“響應”。

下面看看我們把reomve()操作添加到回退棧的情況：

<code class="hljs java has-numbering"><span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">removeFragment1</span>() {
        fragmentManager.beginTransaction().remove(tabFragment1).addToBackStack(<span class="hljs-string">"remove"</span>).commit();
    }</code>

與上面的情況相比，多了TabFragment1的onCreateView()這一步。這是因爲把remove事務添加到了任務棧，回退的時候逆向執行該操作。

使用replace()方法和remove()方法會導致視圖銷燬，所以，切換fragment的時候，如果需要視圖保留視圖，就不能用這兩個方法。

Fragment與Activity之間傳值

fragment –> activity 99%的做法都是通過接口回調來做的。定義一個接口，activity中實現此接口方法，在fragment裏面調用接口方法
activity –> fragment 通過findFragmentById()後者findFragmentByTag()方法獲取fragment實例調用fragment裏的public方法即可。

接着往下看~~

TabFragment2調用接口方法：

<code class="hljs java has-numbering"> <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> View <span class="hljs-title">onCreateView</span>(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        Log.d(<span class="hljs-string">"TabFragment2"</span>, <span class="hljs-string">"onCreateView"</span>);
        View view = inflater.inflate(R.layout.fragment_tab_fragment2, container, <span class="hljs-keyword">false</span>);
        ButterKnife.bind(<span class="hljs-keyword">this</span>, view);
        removeFragmentBtn.setOnClickListener(<span class="hljs-keyword">new</span> View.OnClickListener() {
            <span class="hljs-annotation">@Override</span>
            <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onClick</span>(View v) {
                onBtnClickListener.removeFragment1();
            }
        });
        tellSthBtn.setOnClickListener(<span class="hljs-keyword">new</span> View.OnClickListener() {
            <span class="hljs-annotation">@Override</span>
            <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onClick</span>(View v) {
                onBtnClickListener.tellSth(<span class="hljs-string">"這是我要對你說的話！"</span>);
            }
        });
        <span class="hljs-keyword">return</span> view;
    }
    <span class="hljs-javadoc">/**
     * 回調接口
     */</span>
    <span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">interface</span> <span class="hljs-title">onBtnClickListener</span> {</span>
        <span class="hljs-keyword">void</span> removeFragment1();
        <span class="hljs-keyword">void</span> tellSth(String str);
    }</code>

activity實現該接口的方法：

<code class="hljs java has-numbering"><span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">TestFragments</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">AppCompatActivity</span> <span class="hljs-keyword">implements</span> <span class="hljs-title">TabFragment2</span>.<span class="hljs-title">onBtnClickListener</span> {</span>
    <span class="hljs-annotation">@Bind</span>(R.id.test_fragments_layout)
    FrameLayout testFragmentsLayout;
    <span class="hljs-keyword">private</span> FragmentManager fragmentManager;
    <span class="hljs-keyword">private</span> TabFragment1 tabFragment1;
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">protected</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onCreate</span>(Bundle savedInstanceState) {
        <span class="hljs-keyword">super</span>.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test_fragments2);
        ButterKnife.bind(<span class="hljs-keyword">this</span>);
        fragmentManager = getSupportFragmentManager();
        tabFragment1 = TabFragment1.newInstance();
        fragmentManager.beginTransaction().add(R.id.test_fragments_layout, tabFragment1, <span class="hljs-string">"tab1"</span>).addToBackStack(<span class="hljs-string">"tab1"</span>).commit();
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onBackPressed</span>() {
        <span class="hljs-keyword">super</span>.onBackPressed();
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">removeFragment1</span>() {
        fragmentManager.beginTransaction().remove(tabFragment1).addToBackStack(<span class="hljs-string">"remove"</span>).commit();
    }
    <span class="hljs-annotation">@Override</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">tellSth</span>(String str) {
        ((TabFragment1)fragmentManager.findFragmentByTag(<span class="hljs-string">"tab1"</span>)).showSth(<span class="hljs-string">"hello: "</span> + str);
    }
}</code>

在TabFragment1中定義方法供activity調用：

<code class="hljs cs has-numbering">    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">showSth</span>(String str) {
        getSthEt.setText(str);
    }</code>

Fragment與Fragment傳值

activity給fragment傳值你回了，fragment給activity傳值你也會了。那麼這個問題就不要問我了！！！

Fragment切換動畫

Fragment的切換動畫可以使用系統的標準動畫，也可以自定義動畫。
使用系統的需要用到setTransition()，但是隻能設置系統提供的有限的動畫效果。

FragmentTransaction.TRANSIT_FRAGMENT_OPEN
FragmentTransaction.TRANSIT_FRAGMENT_CLOSE
FragmentTransaction.TRANSIT_FRAGMENT_FADE

自定義動畫需要用到的類：

<code class="hljs java has-numbering"><span class="hljs-javadoc">/**
     * Set specific animation resources to run for the fragments that are
     * entering and exiting in this transaction. These animations will not be
     * played when popping the back stack.
     */</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">abstract</span> FragmentTransaction <span class="hljs-title">setCustomAnimations</span>(@AnimRes <span class="hljs-keyword">int</span> enter,
            @AnimRes <span class="hljs-keyword">int</span> exit);</code>

<code class="hljs java has-numbering"><span class="hljs-javadoc">/**
     * Set specific animation resources to run for the fragments that are
     * entering and exiting in this transaction. The <code>popEnter</code>
     * and <code>popExit</code> animations will be played for enter/exit
     * operations specifically when popping the back stack.
     */</span>
    <span class="hljs-keyword">public</span> <span class="hljs-keyword">abstract</span> FragmentTransaction <span class="hljs-title">setCustomAnimations</span>(@AnimRes <span class="hljs-keyword">int</span> enter,
            @AnimRes <span class="hljs-keyword">int</span> exit, @AnimRes <span class="hljs-keyword">int</span> popEnter, @AnimRes <span class="hljs-keyword">int</span> popExit);</code>

注意：

setCustomAnimations()必須在add()、remove()、replace()調用之前設置，否則不起作用。

比如：有兩個fragment A和B，從A切換到B的時候

@AnimRes int enter
表示Fragment B的進入動畫
@AnimRes int exit
表示Fragment A的退出動畫
@AnimRes int popEnter
表示當從B界面pop回到A時，Fragment A的進入動畫
@AnimRes int popExit
表示當從B界面pop回到A是，Fragment B的退出動畫

如果使用add的方式顯示下一個fragment，則只會觸發enter 和 popExit動畫，因爲這種情況下A並沒有被移除，只是觸發了與B相關的動畫。

比如：
從TabFragment1使用add()方式顯示TabFragment2：

<code class="hljs avrasm has-numbering">FragmentManager fragmentManager = getFragmentManager()<span class="hljs-comment">;</span>
TabFragment2 tabFragment2 = TabFragment2<span class="hljs-preprocessor">.newInstance</span>()<span class="hljs-comment">;</span>
FragmentTransaction fragmentTransaction = fragmentManager<span class="hljs-preprocessor">.beginTransaction</span>()<span class="hljs-comment">;</span>
fragmentTransaction<span class="hljs-preprocessor">.setCustomAnimations</span>(R<span class="hljs-preprocessor">.anim</span><span class="hljs-preprocessor">.slide</span>_in_from_right, R<span class="hljs-preprocessor">.anim</span><span class="hljs-preprocessor">.slide</span>_out_to_left, R<span class="hljs-preprocessor">.anim</span><span class="hljs-preprocessor">.slide</span>_in_from_top, R<span class="hljs-preprocessor">.anim</span><span class="hljs-preprocessor">.slide</span>_out_to_bottom)<span class="hljs-comment">;</span>
fragmentTransaction<span class="hljs-preprocessor">.add</span>(R<span class="hljs-preprocessor">.id</span><span class="hljs-preprocessor">.test</span>_fragments_layout, tabFragment2, <span class="hljs-string">"tab2"</span>)<span class="hljs-comment">;</span>
fragmentTransaction<span class="hljs-preprocessor">.addToBackStack</span>(<span class="hljs-string">"tab2"</span>)<span class="hljs-comment">;</span>
fragmentTransaction<span class="hljs-preprocessor">.commit</span>()<span class="hljs-comment">;</span></code>

4個動畫都是使用的簡單的view動畫，用屬性動畫可以做出更加絢麗的動畫：

slide_in_from_right.xml

<code class="hljs xml has-numbering"><span class="hljs-pi"><?xml version="1.0" encoding="utf-8"?></span>
<span class="hljs-tag"><<span class="hljs-title">translate</span> <span class="hljs-attribute">xmlns:android</span>=<span class="hljs-value">"http://schemas.android.com/apk/res/android"</span>
    <span class="hljs-attribute">android:duration</span>=<span class="hljs-value">"800"</span>
    <span class="hljs-attribute">android:fromXDelta</span>=<span class="hljs-value">"100.0%"</span>
    <span class="hljs-attribute">android:interpolator</span>=<span class="hljs-value">"@android:interpolator/accelerate_decelerate_interpolator"</span>
    <span class="hljs-attribute">android:toXDelta</span>=<span class="hljs-value">"0.0"</span> /></span></code>

slide_out_to_left.xml

<code class="hljs xml has-numbering"><span class="hljs-pi"><?xml version="1.0" encoding="utf-8"?></span>
<span class="hljs-tag"><<span class="hljs-title">translate</span> <span class="hljs-attribute">xmlns:android</span>=<span class="hljs-value">"http://schemas.android.com/apk/res/android"</span>
    <span class="hljs-attribute">android:duration</span>=<span class="hljs-value">"800"</span>
    <span class="hljs-attribute">android:fromXDelta</span>=<span class="hljs-value">"0.0"</span>
    <span class="hljs-attribute">android:interpolator</span>=<span class="hljs-value">"@android:interpolator/accelerate_decelerate_interpolator"</span>
    <span class="hljs-attribute">android:toXDelta</span>=<span class="hljs-value">"-100%"</span> /></span></code>

slide_in_from_top.xml

<code class="hljs xml has-numbering"><span class="hljs-pi"><?xml version="1.0" encoding="utf-8"?></span>
<span class="hljs-tag"><<span class="hljs-title">translate</span> <span class="hljs-attribute">xmlns:android</span>=<span class="hljs-value">"http://schemas.android.com/apk/res/android"</span>
    <span class="hljs-attribute">android:duration</span>=<span class="hljs-value">"1000"</span>
    <span class="hljs-attribute">android:fromYDelta</span>=<span class="hljs-value">"-100.0%"</span>
    <span class="hljs-attribute">android:interpolator</span>=<span class="hljs-value">"@android:interpolator/accelerate_decelerate"</span>
    <span class="hljs-attribute">android:toYDelta</span>=<span class="hljs-value">"0.0"</span> /></span></code>

slide_out_to_bottom.xml

<code class="hljs xml has-numbering"><span class="hljs-pi"><?xml version="1.0" encoding="utf-8"?></span>
<span class="hljs-tag"><<span class="hljs-title">translate</span> <span class="hljs-attribute">xmlns:android</span>=<span class="hljs-value">"http://schemas.android.com/apk/res/android"</span>
    <span class="hljs-attribute">android:duration</span>=<span class="hljs-value">"1000"</span>
    <span class="hljs-attribute">android:fromYDelta</span>=<span class="hljs-value">"0"</span>
    <span class="hljs-attribute">android:interpolator</span>=<span class="hljs-value">"@android:interpolator/accelerate_decelerate"</span>
    <span class="hljs-attribute">android:toYDelta</span>=<span class="hljs-value">"100%p"</span> /></span></code><ul class="pre-numbering" style="display: block;"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li></ul>

效果圖：

如果採用的replace的方式，則會正常的觸發4個動畫。

<code class="hljs avrasm has-numbering">FragmentManager fragmentManager = getFragmentManager()<span class="hljs-comment">;</span>
TabFragment2 tabFragment2 = TabFragment2<span class="hljs-preprocessor">.newInstance</span>()<span class="hljs-comment">;</span>
FragmentTransaction fragmentTransaction = fragmentManager<span class="hljs-preprocessor">.beginTransaction</span>()<span class="hljs-comment">;</span>
fragmentTransaction<span class="hljs-preprocessor">.setCustomAnimations</span>(R<span class="hljs-preprocessor">.anim</span><span class="hljs-preprocessor">.slide</span>_in_from_right, R<span class="hljs-preprocessor">.anim</span><span class="hljs-preprocessor">.slide</span>_out_to_left, R<span class="hljs-preprocessor">.anim</span><span class="hljs-preprocessor">.slide</span>_in_from_top, R<span class="hljs-preprocessor">.anim</span><span class="hljs-preprocessor">.slide</span>_out_to_bottom)<span class="hljs-comment">;</span>
fragmentTransaction<span class="hljs-preprocessor">.replace</span>(R<span class="hljs-preprocessor">.id</span><span class="hljs-preprocessor">.test</span>_fragments_layout, tabFragment2, <span class="hljs-string">"tab2"</span>)<span class="hljs-comment">;</span>
fragmentTransaction<span class="hljs-preprocessor">.addToBackStack</span>(<span class="hljs-string">"tab2"</span>)<span class="hljs-comment">;</span>
fragmentTransaction<span class="hljs-preprocessor">.commit</span>()<span class="hljs-comment">;</span></code>

這裏只介紹了setCustomAnimations()的用法，setTransition()方式的動畫很簡單，就不介紹了。

android中fragment實現

轉載：http://blog.csdn.net/crazy1235/article/details/50933621

Fragment

fragment生命週期

fragment的使用

Fragment的事務管理

Fragment之間的切換

Fragment與Activity之間傳值

Fragment與Fragment傳值

Fragment切換動畫

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android中fragment實現

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