4. fragment与activity的生命周期关系

• Activity 的每次生命周期回调都会引发每个片段的类似回调。例如，当 Activity 收到 onPause() 时，Activity 中的每个片段也会收到 onPause()。

5. 在Activity中动态添加fragment

• 如需执行添加或移除片段等事务，您必须使用 FragmentManager 创建 FragmentTransaction，后者将提供添加、移除、替换片段以及执行其他片段事务所需的 API。
  
• 如果您的 Activity 允许移除和替换片段，应在 Activity 的 onCreate() 方法执行期间为 Activity 添加初始片段。

1. 采用以下方法为之前的布局添加片段：

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();
        }
    }
}

由于该片段已在运行时被添加到 FrameLayout 容器,可以从该Activity 中移除该片段，并将其替换为其他片段。

1. 替换片段：

// Create fragment and give it an argument specifying the article it should show
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();

6. 实例，新闻页面

https://blog.csdn.net/zhaoyanga14/article/details/52166491