Android-20170412
来源:互联网 发布:淘宝店招图片怎么做 编辑:程序博客网 时间:2024/06/06 03:13
Building a Dynamic UI with fragments
1.fragment的创建
新建一个类继承Fragment类,完善它的onCreateView方法。
import android.os.Bundle;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.ViewGroup;public class ArticleFragment extends Fragment { @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment return inflater.inflate(R.layout.article_view, container, false); }}2.用xml布局文件将fragment加入到Activity中
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="fill_parent"> <fragment android:name="com.example.android.fragments.HeadlinesFragment" android:id="@+id/headlines_fragment" android:layout_weight="1" android:layout_width="0dp" android:layout_height="match_parent" /> <fragment android:name="com.example.android.fragments.ArticleFragment" android:id="@+id/article_fragment" android:layout_weight="2" android:layout_width="0dp" android:layout_height="match_parent" /></LinearLayout>自己写的时候测试,id一定要写
3.为Activity添加fragment
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/fragment_container" android:layout_width="match_parent" android:layout_height="match_parent" />
import android.os.Bundle;import android.support.v4.app.FragmentActivity;public class MainActivity extends FragmentActivity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.news_articles); // Check that the activity is using the layout version with // the fragment_container FrameLayout if (findViewById(R.id.fragment_container) != null) { // However, if we're being restored from a previous state, // then we don't need to do anything and should return or else // we could end up with overlapping fragments. if (savedInstanceState != null) { return; } // Create a new Fragment to be placed in the activity layout HeadlinesFragment firstFragment = new HeadlinesFragment(); // In case this activity was started with special instructions from an // Intent, pass the Intent's extras to the fragment as arguments firstFragment.setArguments(getIntent().getExtras()); // Add the fragment to the 'fragment_container' FrameLayout getSupportFragmentManager().beginTransaction() .add(R.id.fragment_container, firstFragment).commit(); } }}官网上用的是v4的包,有点老了,现在用app的包。也不必特意去继承FragmentActivity。
替换Fragment就是将add方法改为replace。
请谨记,当您执行替换或移除片段等片段事务时,通常最好让用户能够回退并“撤消”更改。 要让用户回退所执行的片段事务,您必须先调用addToBackStack()
,然后再提交 FragmentTransaction
。
// Create fragment and give it an argument specifying the article it should showArticleFragment newFragment = new ArticleFragment();Bundle args = new Bundle();args.putInt(ArticleFragment.ARG_POSITION, position);newFragment.setArguments(args);FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();// Replace whatever is in the fragment_container view with this fragment,// and add the transaction to the back stack so the user can navigate backtransaction.replace(R.id.fragment_container, newFragment);transaction.addToBackStack(null);// Commit the transactiontransaction.commit();记住Fragment的操作要使用transaction
4.fragment之间的通信
通信主要依赖搭载这个fragment的activity
activity获取其中fragment的信息:
在fragment实现中定义一个interface,比如叫mCallBack,mCallBack中定义一个用来通信的函数,然后利用在父类中实现这个通信函数来达到获取fragment中信息的目的。
public class HeadlinesFragment extends ListFragment { OnHeadlineSelectedListener mCallback; // Container Activity must implement this interface public interface OnHeadlineSelectedListener { public void onArticleSelected(int position); } @Override public void onAttach(Activity activity) { super.onAttach(activity); // This makes sure that the container activity has implemented // the callback interface. If not, it throws an exception try { mCallback = (OnHeadlineSelectedListener) activity; } catch (ClassCastException e) { throw new ClassCastException(activity.toString() + " must implement OnHeadlineSelectedListener"); } } ...}
@Override public void onListItemClick(ListView l, View v, int position, long id) { // Send the event to the host activity mCallback.onArticleSelected(position); }
public static class MainActivity extends Activity implements HeadlinesFragment.OnHeadlineSelectedListener{ ... public void onArticleSelected(int position) { // The user selected the headline of an article from the HeadlinesFragment // Do something here to display that article }}
public static class MainActivity extends Activity implements HeadlinesFragment.OnHeadlineSelectedListener{ ... public void onArticleSelected(int position) { // The user selected the headline of an article from the HeadlinesFragment // Do something here to display that article ArticleFragment articleFrag = (ArticleFragment) getSupportFragmentManager().findFragmentById(R.id.article_fragment); if (articleFrag != null) { // If article frag is available, we're in two-pane layout... // Call a method in the ArticleFragment to update its content articleFrag.updateArticleView(position); } else { // Otherwise, we're in the one-pane layout and must swap frags... // Create fragment and give it an argument for the selected article ArticleFragment newFragment = new ArticleFragment(); Bundle args = new Bundle(); args.putInt(ArticleFragment.ARG_POSITION, position); newFragment.setArguments(args); FragmentTransaction transaction = getSupportFragmentManager().beginTransaction(); // Replace whatever is in the fragment_container view with this fragment, // and add the transaction to the back stack so the user can navigate back transaction.replace(R.id.fragment_container, newFragment); transaction.addToBackStack(null); // Commit the transaction transaction.commit(); } }}
0 0
- Android-20170412
- Android
- android
- Android
- android
- android
- Android
- Android
- android
- android
- android
- Android
- Android
- android!!!
- android
- android
- android
- android
- 树
- STL-string用法
- scala语言学习笔记
- ArraryList 和 LinkedList 如何选择?
- 第96篇ES与一对一的整合及图像识别跨域问题解决
- Android-20170412
- 网络请求------ContentType(类型) 集合
- 异或^的几个用处
- BZOJ 1251 序列终结者
- Linux下结构体task_struct
- HTTP文件上传实例
- python的奇怪小地方 in numpy
- HDU5423 Rikka with Tree(树,深搜DFS)
- java 运行 linux shell 命令