Fragment的基本使用技巧之add（1）

FragmentTransaction.add把fragment加入到当前的container里面去，commit之后fragment就会自动执行它的生命周期方法，下面是一个简单的fragment使用方法：

package com.example.fragmentdemo;import java.util.List;import com.example.fragmentdemo.fragment.MainFragment;import com.example.fragmentdemo.listener.BackkeyPressListener;import com.example.fragmentdemo.listener.FragmentOp;import android.os.Bundle;import android.app.Activity;import android.content.Context;import android.content.Intent;import android.support.v4.app.Fragment;import android.support.v4.app.FragmentActivity;import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentManager.BackStackEntry;import android.support.v4.app.FragmentManager.OnBackStackChangedListener;import android.support.v4.app.FragmentTransaction;import android.util.AttributeSet;import android.util.Log;import android.view.Menu;import android.view.View;import android.view.ViewGroup;import android.widget.FrameLayout;import android.widget.TextView;public class MainActivity extends FragmentActivity {private String TAG = "MainActivity";private MainActivity mActivity = null;private FragmentManager mFragmentManager = null;private FrameLayout mContainer = null;private TextView titleCenter = null;private MainFragment mMainFragment = null;private String title = null;private FragmentOp mFragmentListener = new FragmentOp() {@Overridepublic void onFragmentReplace(Fragment fragment) {FragmentTransaction ft = mFragmentManager.beginTransaction();ft.replace(R.id.content_layout, fragment, null);ft.commit();}@Overridepublic void onFragmentAdded(Fragment fragment) {setTitle(fragment);FragmentTransaction ft = mFragmentManager.beginTransaction();ft.setCustomAnimations(R.anim.push_up_in, R.anim.push_up_out);ft.add(R.id.content_layout, fragment, title);ft.addToBackStack(fragment.getClass().getName());ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);ft.commit();}};private BackkeyPressListener mBackkeyPressListener = new BackkeyPressListener() {@Overridepublic void onBackkeyPress() {if (0 == mFragmentManager.getBackStackEntryCount()) {mActivity.finish();} else {mFragmentManager.popBackStack();}}};private OnBackStackChangedListener mOnBackStackChangedListener = new OnBackStackChangedListener() {@Overridepublic void onBackStackChanged() {Log.v(TAG, "onBackStackChanged");int count = mFragmentManager.getBackStackEntryCount();Log.v(TAG, "getBackStackEntryCount = " + count);String title = null;if (0 == count) {title = MainFragment.class.getName();} else {BackStackEntry entry = mFragmentManager.getBackStackEntryAt(count - 1);title = entry.getName();}titleCenter.setText(title);}};private void setTitle(Fragment fragment) {title = fragment.getClass().getName();titleCenter.setText(title);}public FragmentManager getMyFragmentManager() {return mFragmentManager;}public BackkeyPressListener getBackkeyPressListener() {return mBackkeyPressListener;}/* * onCreateView ->　onCreate -> onStart -> onResume -> onResumeFragments -> onAttachFragment -> onPostResume * onPause -> onSaveInstanceState -> onStop * @see android.support.v4.app.FragmentActivity#onCreate(android.os.Bundle) */@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);Log.v(TAG, "onCreate");initParams();findWidget();setListener();}private void setListener() {mFragmentManager.addOnBackStackChangedListener(mOnBackStackChangedListener);}private void findWidget() {mContainer= (FrameLayout) this.findViewById(R.id.content_layout);titleCenter = (TextView) this.findViewById(R.id.title_center);}private void initParams() {mFragmentManager = this.getSupportFragmentManager();mActivity = this;}@Overridepublic void onAttachFragment(Fragment fragment) {// TODO 自动生成的方法存根super.onAttachFragment(fragment);Log.v(TAG, "onAttachFragment");}@Overridepublic void onBackPressed() {Log.v(TAG, "onBackPressed");if (null != mBackkeyPressListener) {mBackkeyPressListener.onBackkeyPress();}}@Overridepublic View onCreateView(String name, Context context, AttributeSet attrs) {// TODO 自动生成的方法存根Log.v(TAG, "onCreateView");return super.onCreateView(name, context, attrs);}@Overrideprotected void onDestroy() {// TODO 自动生成的方法存根super.onDestroy();Log.v(TAG, "onDestroy");}@Overrideprotected void onNewIntent(Intent intent) {// TODO 自动生成的方法存根super.onNewIntent(intent);Log.v(TAG, "onNewIntent");}@Overrideprotected void onPause() {// TODO 自动生成的方法存根super.onPause();Log.v(TAG, "onPause");}@Overrideprotected void onPostResume() {// TODO 自动生成的方法存根super.onPostResume();Log.v(TAG, "onPostResume");}@Overrideprotected void onResume() {super.onResume();Log.v(TAG, "onResume");if (null == mMainFragment) {mMainFragment = new MainFragment();mMainFragment.setFragmentListener(mFragmentListener);}title = mMainFragment.getClass().getName();if (!mMainFragment.isAdded()) {FragmentTransaction ft = mFragmentManager.beginTransaction();ft.add(R.id.content_layout, mMainFragment, title);ft.commit();}titleCenter.setText(title);}@Overrideprotected void onResumeFragments() {// TODO 自动生成的方法存根super.onResumeFragments();Log.v(TAG, "onResumeFragments");}@Overridepublic Object onRetainCustomNonConfigurationInstance() {Log.v(TAG, "onRetainCustomNonConfigurationInstance");return super.onRetainCustomNonConfigurationInstance();}@Overrideprotected void onSaveInstanceState(Bundle outState) {// TODO 自动生成的方法存根super.onSaveInstanceState(outState);Log.v(TAG, "onSaveInstanceState");}@Overrideprotected void onStart() {// TODO 自动生成的方法存根super.onStart();Log.v(TAG, "onStart");}@Overrideprotected void onStop() {// TODO 自动生成的方法存根super.onStop();Log.v(TAG, "onStop");}}

上面是Activity控制中心， 负责控制fragment的add、replace，下面是一个fragment，从中可以看出fragmetn的生命周期及基本使用方法，其实它与一般的UI组件类似，之不过它更灵活，它有自己的生命 控制周期，从这点来看它又像是一个特殊的Activitiy，其实它与Activity差不多，只不过它必须依附于Activity运行，当Activity运行到可交互状态后才能自由的在代码中添加、删除的自己fragment，看代码：

package com.example.fragmentdemo.fragment;import com.example.fragmentdemo.R;import com.example.fragmentdemo.listener.FragmentOp;import android.app.Activity;import android.content.Context;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.View.OnClickListener;import android.view.ViewGroup;import android.widget.Button;public class MainFragment extends Fragment {private String TAG = "MainFragment";private View mView = null;private Activity mActivity = null;private Context mContext = null;private Button btn = null;private FragmentOp listener = null;private NestedFragment mNestedFragment = null;public MainFragment() {// TODO 自动生成的构造函数存根}public void setFragmentListener(FragmentOp l) {this.listener = l;}/* * onAttach -> onCreate -> onCreateView -> onActivityCreated -> onStart -> onResume * onPause -> onStop -> onDestoryView -> onDestory -> onDettach * @see android.support.v4.app.Fragment#onActivityCreated(android.os.Bundle) */@Overridepublic void onActivityCreated(Bundle savedInstanceState) {// TODO 自动生成的方法存根super.onActivityCreated(savedInstanceState);Log.v(TAG, "onActivityCreated");}@Overridepublic void onAttach(Activity activity) {// TODO 自动生成的方法存根super.onAttach(activity);Log.v(TAG, "onAttach");this.mActivity = activity;this.mContext = activity.getApplicationContext();}@Overridepublic void onCreate(Bundle savedInstanceState) {// TODO 自动生成的方法存根super.onCreate(savedInstanceState);Log.v(TAG, "onCreate");}@Overridepublic void onPause() {// TODO 自动生成的方法存根super.onPause();Log.v(TAG, "onPause");}@Overridepublic void onResume() {// TODO 自动生成的方法存根super.onResume();Log.v(TAG, "onResume");}@Overridepublic void onStart() {// TODO 自动生成的方法存根super.onStart();Log.v(TAG, "onStart");}@Overridepublic void onStop() {// TODO 自动生成的方法存根super.onStop();Log.v(TAG, "onStop");}@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {// TODO 自动生成的方法存根Log.v(TAG, "onCreateView");this.mView = inflater.inflate(R.layout.main_layout, container, false);findWidget();setListener();return mView;}private void findWidget() {btn = (Button) this.mView.findViewById(R.id.btn);}private void setListener() {btn.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View view) {if (null == mNestedFragment) {mNestedFragment = new NestedFragment();mNestedFragment.setFragmentListener(listener);}if (null != listener) {listener.onFragmentAdded(mNestedFragment);}}});}@Overridepublic void onDestroy() {// TODO 自动生成的方法存根super.onDestroy();Log.v(TAG, "onDestroy");}@Overridepublic void onDestroyView() {// TODO 自动生成的方法存根super.onDestroyView();Log.v(TAG, "onDestroyView");}@Overridepublic void onDetach() {// TODO 自动生成的方法存根super.onDetach();Log.v(TAG, "onDetach");}}

代码的整个工程连接如下：

源代码