import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import androidx.annotation.NonNull; import androidx.annotation.Nullable; import androidx.fragment.app.Fragment; * @author xujiayi * @date 2023/11/5 * 我只是个自由的主！ public abstract class BaseFragment extends Fragment { public static final String TAG = "BaseFragment" ; * 视图是否初始化 protected boolean isInit = false ; protected boolean isLoad = false ; private View mView; @Nullable @Override public View onCreateView ( @NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { //加载子view mView = onSubViewLoaded(inflater, container); isInit = true ; //初始化的时候去加载数据 isCanLoadData(); return mView; * 是否可以加载数据 * 可以加载数据的条件： * 1.视图已经初始化 * 2.视图对用户可见 private void isCanLoadData () { if (!isInit) return ; Log.d(TAG, "isCanLoadData: " +getUserVisibleHint()); if (getUserVisibleHint()&&!isLoad) { lazyLoadData(); isLoad = true ; } else { if (isLoad) stopLoadData(); public abstract View createSuccess (LayoutInflater inflater, ViewGroup container) ; * 当视图初始化并且对用户可见的时候去真正的加载数据 protected abstract void lazyLoadData () ; * 当视图已经对用户不可见并且加载过数据，如果需要在切换到其他页面时停止加载数据，可以覆写此方法 protected void stopLoadData () { protected abstract View onSubViewLoaded (LayoutInflater inflater, ViewGroup container) ; @Override public void onDestroyView () { super .onDestroyView(); isInit = false ; isLoad = false ; @Override public void setUserVisibleHint ( boolean isVisibleToUser) { super .setUserVisibleHint(isVisibleToUser); isCanLoadData(); java package cool.hyz.xujiayi.base; import android.os.Bundle; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import androidx.annotation.NonNull; import androidx.annotation.Nullable; import androidx.fragment.app.Fragment; * @author xujiayi * @date 2023/11/5 * 我只是个自由的主！ public abstract class BaseFragment extends Fragment { public static final String TAG = "BaseFragment"; * 视图是否初始化 protected boolean isInit = false; protected boolean isLoad = false; private View mView; @Nullable @Override public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { //加载子view mView = onSubViewLoaded(inflater, container); isInit = true; //初始化的时候去加载数据 isCanLoadData(); return mView; * 是否可以加载数据 * 可以加载数据的条件： * 1.视图已经初始化 * 2.视图对用户可见 private void isCanLoadData() { if (!isInit) return; Log.d(TAG, "isCanLoadData: "+getUserVisibleHint()); if (getUserVisibleHint()&&!isLoad) { lazyLoadData(); isLoad = true; } else { if (isLoad) stopLoadData(); public abstract View createSuccess(LayoutInflater inflater, ViewGroup container); * 当视图初始化并且对用户可见的时候去真正的加载数据 protected abstract void lazyLoadData(); * 当视图已经对用户不可见并且加载过数据，如果需要在切换到其他页面时停止加载数据，可以覆写此方法 protected void stopLoadData() { protected abstract View onSubViewLoaded(LayoutInflater inflater, ViewGroup container); @Override public void onDestroyView() { super.onDestroyView(); isInit = false; isLoad = false; @Override public void setUserVisibleHint(boolean isVisibleToUser) { super.setUserVisibleHint(isVisibleToUser); isCanLoadData(); <li>实现<code>BaseFragment</code></li> <pre class="hljs"><code><button class="copy-btn iconfont icon-copy" type="button" data-clipboard-action="copy" data-clipboard-target="#copy3e035742-a933-4cfa-8a86-9a886b2c1580"/><span class="hljs-keyword">package</span> cool.hyz.xujiayi.views.home; <span class="hljs-keyword">import</span> android.content.Intent; <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> java.util.List; <span class="hljs-keyword">import</span> cool.hyz.xujiayi.R; <span class="hljs-keyword">import</span> cool.hyz.xujiayi.base.BaseFragment; * <span class="hljs-doctag">@author</span> xujiayi * <span class="hljs-doctag">@date</span> 2023/11/5 * 我只是个自由的主！ <span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">HomeFragment</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">BaseFragment</span> </span>{ <span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">final</span> String TAG = <span class="hljs-string">"HomeFragment"</span>; <span class="hljs-keyword">private</span> Banner mBannerH; <span class="hljs-keyword">private</span> Banner mBannerV; <span class="hljs-keyword">private</span> View mRoot; <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-title">HomeFragment</span><span class="hljs-params">()</span> </span>{ <span class="hljs-meta">@Override</span> <span class="hljs-function"><span class="hljs-keyword">protected</span> <span class="hljs-keyword">void</span> <span class="hljs-title">lazyLoadData</span><span class="hljs-params">()</span> </span>{ Log.d(TAG, <span class="hljs-string">"lazyLoadData: HomeView load data..."</span>); <span class="hljs-meta">@Override</span> <span class="hljs-function"><span class="hljs-keyword">protected</span> View <span class="hljs-title">onSubViewLoaded</span><span class="hljs-params">(LayoutInflater inflater, ViewGroup container)</span> </span>{ mRoot = inflater.inflate(R.layout.fragment_home, container, <span class="hljs-keyword">false</span>); <span class="hljs-keyword">return</span> mRoot ; <span class="hljs-meta">@Override</span> <span class="hljs-function"><span class="hljs-keyword">protected</span> <span class="hljs-keyword">void</span> <span class="hljs-title">stopLoad</span><span class="hljs-params">()</span> </span>{ Log.d(TAG, <span class="hljs-string">"HomeFragment"</span> + <span class="hljs-string">"已经对用户不可见，可以停止加载数据"</span>); <b class="name">java</b></code><span aria-hidden="true" class="line-numbers-rows"><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/></span></pre><textarea style="position: absolute;top: -9999px;left: -9999px;z-index: -9999;" id="copy3e035742-a933-4cfa-8a86-9a886b2c1580">package cool.hyz.xujiayi.views.home; import android.content.Intent; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import java.util.List; import cool.hyz.xujiayi.R; import cool.hyz.xujiayi.base.BaseFragment; * @author xujiayi * @date 2023/11/5 * 我只是个自由的主！ public class HomeFragment extends BaseFragment { public static final String TAG = "HomeFragment"; private Banner mBannerH; private Banner mBannerV; private View mRoot; public HomeFragment() { @Override protected void lazyLoadData() { Log.d(TAG, "lazyLoadData: HomeView load data..."); @Override protected View onSubViewLoaded(LayoutInflater inflater, ViewGroup container) { mRoot = inflater.inflate(R.layout.fragment_home, container, false); return mRoot ; @Override protected void stopLoad() { Log.d(TAG, "HomeFragment" + "已经对用户不可见，可以停止加载数据"); <li><s><code>getUserVisibleHint()</code></s> Deprecated;</li> <li><s><code>setUserVisibleHint(boolean)</code></s> Deprecated;</li> <li>使用<code>FragmentPagerAdapter</code>时直接使用两个参数的构造方法<code>FragmentPagerAdapter(fragmentManager, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT)</code></li> <pre class="hljs"><code><button class="copy-btn iconfont icon-copy" type="button" data-clipboard-action="copy" data-clipboard-target="#copy6eff2782-8774-49e1-a143-a1aa520bccde"/><span class="hljs-keyword">package</span> cool.hyz.xujiayi.adapters; <span class="hljs-keyword">import</span> android.view.ViewGroup; <span class="hljs-keyword">import</span> androidx.annotation.NonNull; <span class="hljs-keyword">import</span> androidx.fragment.app.Fragment; <span class="hljs-keyword">import</span> androidx.fragment.app.FragmentManager; <span class="hljs-keyword">import</span> androidx.fragment.app.FragmentPagerAdapter; <span class="hljs-keyword">import</span> cool.hyz.xujiayi.creators.FragmentCreator; <span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">FragPagerAdapter</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">FragmentPagerAdapter</span> </span>{ <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-title">FragPagerAdapter</span><span class="hljs-params">(<span class="hljs-meta">@NonNull</span> FragmentManager fm)</span> </span>{ <span class="hljs-keyword">super</span>(fm, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT); <span class="hljs-meta">@NonNull</span> <span class="hljs-meta">@Override</span> <span class="hljs-function"><span class="hljs-keyword">public</span> Fragment <span class="hljs-title">getItem</span><span class="hljs-params">(<span class="hljs-keyword">int</span> position)</span> </span>{ <span class="hljs-keyword">return</span> FragmentCreator.getFragment(position); <span class="hljs-meta">@Override</span> <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">int</span> <span class="hljs-title">getCount</span><span class="hljs-params">()</span> </span>{ <span class="hljs-keyword">return</span> FragmentCreator.PAGE_COUNT; <span class="hljs-meta">@Override</span> <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">destroyItem</span><span class="hljs-params">(<span class="hljs-meta">@NonNull</span> ViewGroup container, <span class="hljs-keyword">int</span> position, <span class="hljs-meta">@NonNull</span> Object object)</span> </span>{ <span class="hljs-comment">//切换时不销毁page</span> <span class="hljs-comment">//super.destroyItem(container, position, object);</span> <b class="name">java</b></code><span aria-hidden="true" class="line-numbers-rows"><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/></span></pre><textarea style="position: absolute;top: -9999px;left: -9999px;z-index: -9999;" id="copy6eff2782-8774-49e1-a143-a1aa520bccde">package cool.hyz.xujiayi.adapters; import android.view.ViewGroup; import androidx.annotation.NonNull; import androidx.fragment.app.Fragment; import androidx.fragment.app.FragmentManager; import androidx.fragment.app.FragmentPagerAdapter; import cool.hyz.xujiayi.creators.FragmentCreator; public class FragPagerAdapter extends FragmentPagerAdapter { public FragPagerAdapter(@NonNull FragmentManager fm) { super(fm, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT); @NonNull @Override public Fragment getItem(int position) { return FragmentCreator.getFragment(position); @Override public int getCount() { return FragmentCreator.PAGE_COUNT; @Override public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) { //切换时不销毁page //super.destroyItem(container, position, object); <li>通过<code>FragmentTransaction</code>的<code>setMaxLifecycle()</code>方法——替代<code>setUserVisibleHint()</code>方法实现<code>Fragment</code>的懒加载效果。</li> <li><code>instantiateItem()</code>中<code>setMaxLifecycle()</code>设置的<code>Fragment</code>状态为<code>STARTED</code>，即通过<code>ViewPager.offscreenPageLimit</code>设置提前初始化时，临近的<code>Fragment</code>最多执行到<code>onStart()</code>方法，不会再执行<code>onResume()</code>方法了</li> <li>如果需要<code>Fragment</code>只执行一次对应逻辑且<code>Fragment</code>重新加载<code>View</code>时需要重置，之前通常会通过<code>setUserVisibleHint(isVisibleToUser: Boolean)</code>里通过<code>isVisibleToUser</code>以及自定义的<code>isLoaded</code>去判断，现在可以直接将逻辑写到<code>onResume</code>中:</li> <span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">HomeFragment</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">BaseFragment</span> </span>{ <span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">final</span> String TAG = <span class="hljs-string">"HomeFragment"</span>; <span class="hljs-keyword">private</span> <span class="hljs-keyword">boolean</span> isLoaded = <span class="hljs-keyword">false</span>; <span class="hljs-meta">@Override</span> <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onResume</span><span class="hljs-params">()</span> </span>{ <span class="hljs-keyword">super</span>.onResume(); <span class="hljs-keyword">if</span>(!isLoaded){ <span class="hljs-comment">//<span class="hljs-doctag">TODO:</span> 数据加载</span> isLoaded = <span class="hljs-keyword">true</span>; <span class="hljs-meta">@Override</span> <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onDestroyView</span><span class="hljs-params">()</span> </span>{ <span class="hljs-keyword">super</span>.onDestroyView(); isLoaded = <span class="hljs-keyword">false</span>; <b class="name">java</b></code><span aria-hidden="true" class="line-numbers-rows"><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/><span/></span></pre><textarea style="position: absolute;top: -9999px;left: -9999px;z-index: -9999;" id="copy19a0ea0c-0f1b-4dfb-a41a-649fa3461b27">... public class HomeFragment extends BaseFragment { public static final String TAG = "HomeFragment"; private boolean isLoaded = false; @Override public void onResume() { super.onResume(); if(!isLoaded){ //TODO: 数据加载 isLoaded = true; @Override public void onDestroyView() { super.onDestroyView(); isLoaded = false; <li><a href="https://blog.csdn.net/linglongxin24/article/details/53205878">Android中ViewPager+Fragment取消(禁止)预加载延迟加载(懒加载)问题解决方案</a></li> <li><a href="https://blog.csdn.net/u013700502/article/details/127653482">Fragment.setUserVisibleHint()懒加载过时问题优化</a></li> </article> <div class="aritcle-copyright" data-v-5bcc836c=""><div data-v-5bcc836c=""><span data-v-5bcc836c="">文章作者：</span> <a href="/" target="_blank" class="nuxt-link-active" data-v-5bcc836c=""> </a></div> <div data-v-5bcc836c=""><span data-v-5bcc836c="">文章链接：</span> <a href="" target="_blank" data-v-5bcc836c=""> </a></div> <!----> <div data-v-5bcc836c=""><span data-v-5bcc836c="">版权声明：</span>本博客所有文章除特别声明外，均采用 CC BY-NC-SA 4.0 许可协议。转载请注明文章出处。 android Fragment <div class="animated zoomIn 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