Fragment 整个生命周期演示

来源：互联网发布：php rsasig 编辑：程序博客网时间：2024/05/22 17:49

Fragment生命周期主要体现在以下表中13个方法里，以下是按照Fragment从开始到销毁的先后执行顺序排序。

序号

方法名称

描述

public void onInflate(Activity activity, AttributeSet attrs,BundlesavedInstanceState)

在Activity.onCreate方法之前调用，可以获取除了View之外的资源

public void onAttach(Activity activity)

当fragment第一次与Activity产生关联时就会调用，以后不再调用

public void onCreate(Bundle savedInstanceState)

在onAttach执行完后会立刻调用此方法，通常被用于读取保存的状态值，获取或者初始化一些数据，但是该方法不执行，窗口是不会显示的，因此如果获取的数据需要访问网络，最好新开线程。

public View onCreateView(LayoutInflater inflater, ViewGroup container,

Bundle savedInstanceState)

作用：创建Fragment中显示的view,其中inflater用来装载布局文件，container表示<fragment>标签的父标签对应的ViewGroup对象，savedInstanceState可以获取Fragment保存的状态

public void onViewCreated(View view, Bundle savedInstanceState)

继上面后就会调用此方法

public void onActivityCreated(Bundle savedInstanceState)

在Activity.onCreate方法调用后会立刻调用此方法，表示窗口已经初始化完毕，此时可以调用控件了

public void onStart()

开始执行与控件相关的逻辑代码，如按键点击

public void onResume()

这是Fragment从创建到显示的最后一个回调的方法

public void onPause()

当发生界面跳转时，临时暂停，暂停时间是500ms,0.5s后直接进入下面的onStop方法

public void onStop()

当该方法返回时，Fragment将从屏幕上消失

public void onDestroyView()

当fragment状态被保存，或者从回退栈弹出，该方法被调用

public void onDestroy()

当Fragment不再被使用时，如按返回键，就会调用此方法

public void onDetach()

Fragment生命周期的最后一个方法，执行完后将不再与Activity关联，将释放所有fragment对象和资源

下面进行一个demo来观察fragment生命周期，

（1）从启动到显示整个界面：

点击跳转到第二个Actvity时的情况——

可以看到，依次调用onPause() 和 onStop()方法；观察其时间，可以发现就是相差500ms ;

当再次返回到这两个fragment时

当点击返回键，直接回到主界面时，可以看到fragment销毁并退出了

至此，Fragment的生命周期一览无余。

代码如下：

[java] view plaincopy

public class MyFragment1 extends Fragment
{
private Button button1;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
Log.d("Fragment1", "onCreateView");
View view = inflater.inflate(R.layout.my_fragment1, null);
Log.d("Fragment1_onCreateView_getActivity_edittext1",
String.valueOf(getActivity().findViewById(R.id.edittext1)));
Log.d("Fragment1_onCreateView_view_edittext1",
String.valueOf(view.findViewById(R.id.edittext1)));
button1 = (Button)view.findViewById(R.id.button1);
button1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent = new Intent(getActivity(), MainActivity.class);
startActivity(intent);
}
});
return view;
}
@Override
public void onInflate(Activity activity, AttributeSet attrs,
Bundle savedInstanceState)
{
Log.d("Fragment1", "onInflate");
Log.d("Fragment1_onInflate_activity_stringResource", activity
.getResources().getString(R.string.app_name));
Log.d("Fragment1_onInflate_class",
attrs.getAttributeValue(null, "class"));
Log.d("Fragment1_onInflate_getActivity", String.valueOf(getActivity()));
Log.d("Fragment1_onInflate_activity_edittext1",
String.valueOf(activity.findViewById(R.id.edittext1)));
Log.d("Fragment1_onInflate_savedInstanceState",
String.valueOf(savedInstanceState));
super.onInflate(activity, attrs, savedInstanceState);
}
@Override
public void onAttach(Activity activity)
{
Log.d("Fragment1", "onAttach");
Log.d("Fragment1_onAttach_activity_edittext1",
String.valueOf(activity.findViewById(R.id.edittext1)));
Log.d("Fragment1_onAttach_getActivity_edittext1",
String.valueOf(getActivity().findViewById(R.id.edittext1)));
super.onAttach(activity);
}
@Override
public void onCreate(Bundle savedInstanceState)
{
Log.d("Fragment1", "onCreate");
Log.d("Fragment1_onCreate_getActivity", String.valueOf(getActivity()));
super.onCreate(savedInstanceState);
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState)
{
Log.d("Fragment1", "onViewCreated");
Log.d("Fragment1_onViewCreated_getActivity_edittext1",
String.valueOf(getActivity().findViewById(R.id.edittext1)));
Log.d("Fragment1_onViewCreated_view_edittext1",
String.valueOf(view.findViewById(R.id.edittext1)));
super.onViewCreated(view, savedInstanceState);
}
@Override
public void onActivityCreated(Bundle savedInstanceState)
{
Log.d("Fragment1", "onActivityCreated");
Log.d("Fragment1_onActivityCreated_getActivity_edittext1",
String.valueOf(getActivity().findViewById(R.id.edittext1)));
super.onActivityCreated(savedInstanceState);
}
@Override
public void onStart()
{
Log.d("Fragment1", "onStart");
super.onStart();
}
@Override
public void onResume()
{
Log.d("Fragment1", "onResume");
super.onResume();
}
@Override
public void onPause()
{
Log.d("Fragment1", System.currentTimeMillis()+"onPause");
super.onPause();
}
@Override
public void onStop()
{
Log.d("Fragment1", System.currentTimeMillis()+"onStop");
super.onStop();
}
@Override
public void onDestroyView()
{
Log.d("Fragment1", "onDestroyView");
super.onDestroyView();
}
@Override
public void onDestroy()
{
Log.d("Fragment1", System.currentTimeMillis()+"onDestroy");
super.onDestroy();
}
@Override
public void onDetach()
{
Log.d("Fragment1", "onDetach");
super.onDetach();
}
}

[java] view plaincopy

public class MyFragment1 extends Fragment
{
private Button button1;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
Log.d("Fragment1", "onCreateView");
View view = inflater.inflate(R.layout.my_fragment1, null);
Log.d("Fragment1_onCreateView_getActivity_edittext1",
String.valueOf(getActivity().findViewById(R.id.edittext1)));
Log.d("Fragment1_onCreateView_view_edittext1",
String.valueOf(view.findViewById(R.id.edittext1)));
button1 = (Button)view.findViewById(R.id.button1);
button1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent = new Intent(getActivity(), MainActivity.class);
startActivity(intent);
}
});
return view;
}
@Override
public void onInflate(Activity activity, AttributeSet attrs,
Bundle savedInstanceState)
{
Log.d("Fragment1", "onInflate");
Log.d("Fragment1_onInflate_activity_stringResource", activity
.getResources().getString(R.string.app_name));
Log.d("Fragment1_onInflate_class",
attrs.getAttributeValue(null, "class"));
Log.d("Fragment1_onInflate_getActivity", String.valueOf(getActivity()));
Log.d("Fragment1_onInflate_activity_edittext1",
String.valueOf(activity.findViewById(R.id.edittext1)));
Log.d("Fragment1_onInflate_savedInstanceState",
String.valueOf(savedInstanceState));
super.onInflate(activity, attrs, savedInstanceState);
}
@Override
public void onAttach(Activity activity)
{
Log.d("Fragment1", "onAttach");
Log.d("Fragment1_onAttach_activity_edittext1",
String.valueOf(activity.findViewById(R.id.edittext1)));
Log.d("Fragment1_onAttach_getActivity_edittext1",
String.valueOf(getActivity().findViewById(R.id.edittext1)));
super.onAttach(activity);
}
@Override
public void onCreate(Bundle savedInstanceState)
{
Log.d("Fragment1", "onCreate");
Log.d("Fragment1_onCreate_getActivity", String.valueOf(getActivity()));
super.onCreate(savedInstanceState);
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState)
{
Log.d("Fragment1", "onViewCreated");
Log.d("Fragment1_onViewCreated_getActivity_edittext1",
String.valueOf(getActivity().findViewById(R.id.edittext1)));
Log.d("Fragment1_onViewCreated_view_edittext1",
String.valueOf(view.findViewById(R.id.edittext1)));
super.onViewCreated(view, savedInstanceState);
}
@Override
public void onActivityCreated(Bundle savedInstanceState)
{
Log.d("Fragment1", "onActivityCreated");
Log.d("Fragment1_onActivityCreated_getActivity_edittext1",
String.valueOf(getActivity().findViewById(R.id.edittext1)));
super.onActivityCreated(savedInstanceState);
}
@Override
public void onStart()
{
Log.d("Fragment1", "onStart");
super.onStart();
}
@Override
public void onResume()
{
Log.d("Fragment1", "onResume");
super.onResume();
}
@Override
public void onPause()
{
Log.d("Fragment1", System.currentTimeMillis()+"onPause");
super.onPause();
}
@Override
public void onStop()
{
Log.d("Fragment1", System.currentTimeMillis()+"onStop");
super.onStop();
}
@Override
public void onDestroyView()
{
Log.d("Fragment1", "onDestroyView");
super.onDestroyView();
}
@Override
public void onDestroy()
{
Log.d("Fragment1", System.currentTimeMillis()+"onDestroy");
super.onDestroy();
}
@Override
public void onDetach()
{
Log.d("Fragment1", "onDetach");
super.onDetach();
}
}

演示Demo 下载

使用Fragmen的好处就是可以把业务逻辑和UI封装在一起，与外部关联系不大，其他程序也可以用该组件，从而实现复用最大化。

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