(十五)——碎片的生命周期(附源码)
最后更新于:2022-04-01 20:17:02
**碎片的生命周期**
**[点击下载源码](http://download.csdn.net/detail/u012904198/7336969)**
与活动类似,碎片具有自己的生命周期。理解了碎片的生命周期后,我们可以在碎片被销毁时正确地保存其实例,在碎片被重建时将其还原到前一个状态。
1、使用上一篇的项目Fragments,在Fragment1.java文件中添加如下代码:
~~~
package net.zenail.Fragments;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Fragment1 extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
Log.d("Fragment 1", "onCreateView");
// 实例化布局文件
return inflater.inflate(R.layout.fragment1, container, false);
}
@Override
public void onAttach(Activity activity) {
// TODO Auto-generated method stub
super.onAttach(activity);
Log.d("Fragment 1", "onAttach");
}
@Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
Log.d("Fragment 1", "onCreate");
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onActivityCreated(savedInstanceState);
Log.d("Fragment 1", "onActivityCreated");
}
@Override
public void onStart() {
// TODO Auto-generated method stub
super.onStart();
Log.d("Fragment 1", "onStart");
}
@Override
public void onResume() {
// TODO Auto-generated method stub
super.onResume();
Log.d("Fragment 1", "onResume");
}
@Override
public void onPause() {
super.onPause();
Log.d("Fragment 1", "onPause");
};
public void onStop() {
// TODO Auto-generated method stub
super.onStop();
Log.d("Fragment 1", "onStop");
}
@Override
public void onDestroyView() {
// TODO Auto-generated method stub
super.onDestroyView();
Log.d("Fragment 1", "onDestroyView");
}
@Override
public void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
Log.d("Fragment 1", "onDestroy");
}
@Override
public void onDetach() {
// TODO Auto-generated method stub
super.onDetach();
Log.d("Fragment 1", "onDetach");
}
}
~~~
2、按Ctrl+F11,将Android模拟器切换到横向模式;
3、在Eclipse中按下F11键,在模拟器上调试应用程序;
4、当应用程序加载到模拟器中后,LogCat窗口会显示如下内容:
![](https://docs.gechiui.com/gc-content/uploads/sites/kancloud/2016-08-23_57bc06b8cdc1e.jpg)
5、单击模拟器上的Home按钮,LogCat窗口中显示如下输出:
![](https://docs.gechiui.com/gc-content/uploads/sites/kancloud/2016-08-23_57bc06b8e3066.jpg)
6、在模拟器上长按Home按钮,再单击Fragments以启动应用程序,LogCat显示如下:
![](https://docs.gechiui.com/gc-content/uploads/sites/kancloud/2016-08-23_57bc06b9050d1.jpg)
7、最后,单击模拟器中Back按钮,LogCat窗口显示如下输出:
![](https://docs.gechiui.com/gc-content/uploads/sites/kancloud/2016-08-23_57bc06b918f5a.jpg)
8、由上面的实例可知,碎片经历的过程如下:
碎片被创建时:onAttach()-->onCreate()-->onCreateView()-->onActivityCreated();
碎片进入后台模式时:onPause()-->onStop();
碎片变为可见时:onStart()-->onResume();
碎片被销毁时:onPause()-->onStop()-->onDestroyView()-->onDestroy()-->onDetach();
9、与活动一样,碎片可以使用Bundle对象在以下状态中还原碎片的实例:
onCreate()、onCreateView()、onActivityCreated()。
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