在講述Fragment的生命週期之前,我覺得有必要先對Fragment做一個簡單的介紹,閱讀英文文檔沒問題的同學,建議直接閱讀官方文檔,本人也是菜鳥,這邊的簡單介紹也只是對閱讀過官方文檔與查閱相關資料後做的一個簡單的總結(所以還是建議閱讀官方文檔,畢竟每個人的理解會有所出入)。
Fragment簡介
Fragment生命週期
Fragment用法
示例
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:gravity="center" >
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="I am a Fragment!"
android:gravity="center" />
</LinearLayout>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<LinearLayout
android:id="@+id/line"
android:layout_width="match_parent"
android:layout_height="150dip"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginTop="150dip"
android:background="#FFFF0000"
android:orientation="vertical" >
</LinearLayout>
</RelativeLayout>
4.創建一個類,繼承自Fragment,此處我定義的類名爲Fragment,其實現如下所示,爲每個方法都添加了Log輸出
package com.example.android_fragment_lifetime;
import android.app.Activity;
import android.app.Fragment;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class MyFragment extends Fragment {
private final static String TAG = "MyFragment";
@Override
public void onAttach(Activity activity) {
// TODO Auto-generated method stub
super.onAttach(activity);
Log.e(TAG, "-MyFragment- onAttach ->>");
}
@Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
Log.e(TAG, "-MyFragment- onCreate ->>");
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
Log.e(TAG, "-MyFragment- onCreateView ->>");
View view = inflater.inflate(R.layout.ff, null);
//return super.onCreateView(inflater, container, savedInstanceState);
return view;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onActivityCreated(savedInstanceState);
Log.e(TAG, "-MyFragment- onActivityCreated ->>");
}
@Override
public void onStart() {
// TODO Auto-generated method stub
super.onStart();
Log.e(TAG, "-MyFragment- onStart ->>");
}
@Override
public void onResume() {
// TODO Auto-generated method stub
super.onResume();
Log.e(TAG, "-MyFragment- onResume ->>");
}
@Override
public void onPause() {
// TODO Auto-generated method stub
super.onPause();
Log.e(TAG, "-MyFragment- onPause ->>");
}
@Override
public void onStop() {
// TODO Auto-generated method stub
super.onStop();
Log.e(TAG, "-MyFragment- onStop ->>");
}
@Override
public void onDestroyView() {
// TODO Auto-generated method stub
super.onDestroyView();
Log.e(TAG, "-MyFragment- onDestroyView ->>");
}
@Override
public void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
Log.e(TAG, "-MyFragment- onDestroy ->>");
}
@Override
public void onDetach() {
// TODO Auto-generated method stub
super.onDetach();
Log.e(TAG, "-MyFragment- onDetach ->>");
}
}
5.修改程序入口的Activity(默認爲MainActivity)
package com.example.android_fragment_lifetime;
import android.os.Bundle;
import android.app.Activity;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.util.Log;
import android.view.Menu;
public class MainActivity extends Activity {
private final static String TAG = "MainActivity";
FragmentManager manager;
FragmentTransaction transaction;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.e(TAG, "-MainActivity- onCreate ->>");
manager = getFragmentManager(); //獲取該Activity的FragmentManager
transaction = manager.beginTransaction(); //啓動Fragment業務
MyFragment myFragment = new MyFragment();
transaction.add(R.id.line, myFragment); //添加一個操作業務,爲指定區域添加一個Fragment
transaction.commit(); //提交Fragment的操作
}
@Override
protected void onRestart() {
// TODO Auto-generated method stub
super.onRestart();
Log.e(TAG, "-MainActivity- onRestart ->>");
}
@Override
protected void onStart() {
// TODO Auto-generated method stub
super.onStart();
Log.e(TAG, "-MainActivity- onStart ->>");
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
Log.e(TAG, "-MainActivity- onResume ->>");
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
Log.e(TAG, "-MainActivity- onPause ->>");
}
@Override
protected void onStop() {
// TODO Auto-generated method stub
super.onStop();
Log.e(TAG, "-MainActivity- onStop ->>");
}
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
Log.e(TAG, "-MainActivity- onDestroy ->>");
}
}
6.運行這個Android應用,發現程序中間潛入了我們的文本數據“I am a Fragment”