首选项框架PreferenceFragment部分源代码分析

     由于要改一些settings里面的bug以及之前在里面有做过勿扰模式，准备对勿扰模式做一个总结，那先分析一下settings的源代码，里面的核心应该就是android3.0 上面的首选项框架PreferenceFragment。

由于在3.0之前都是把这些东西放在PreferenceActivity的，可是3.0之后google建议把setting放在PreferenceFragment，可是PreferenceActivity也同一时候在用的，以下就此总结一下：

     PreferenceActivity的作用是管理全部headers，而每个header相应一个PreferenceFragment，相应不同的设置种类界面所以我感觉PreferenceActivity偏向系统级的设置，就比方android系统的settings。对于一些简单的应用设置一个PreferenceFragment是能够搞定的。

     我们自己定义一个 activity extends PreferenceActivity必须重写onBuildHeaders()这个方法，在这里载入一个xml布局显示：

@Override
	public void onBuildHeaders(List<Header> target) {
		// TODO Auto-generated method stub
		loadHeadersFromResource(R.xml.activity_headers, target);
	}

<?xml version="1.0" encoding="utf-8"?>
<preference-headers xmlns:android="http://schemas.android.com/apk/res/android" >
    <header
        android:id="@+id/wifi"
        android:title="wifi"
        android:icon="@drawable/ic_launcher"
        android:fragment="com.example.preferencefragmenttest.WifiFragment"/>
    
     <header
        android:id="@+id/net"
        android:title="移动网络"
        android:icon="@drawable/ic_launcher"
        android:fragment="com.example.preferencefragmenttest.NetFragment"/>
     
     <header
        android:id="@+id/ee"
        android:title="打开activity"
        android:icon="@drawable/ic_launcher"
        >
        <intent android:action="android.intent.action.NEW"></intent>
</header>
</preference-headers>

public void onHeaderClick(Header header, int position) {
        if (header.fragment != null) {
            if (mSinglePane) {
                int titleRes = header.breadCrumbTitleRes;
                int shortTitleRes = header.breadCrumbShortTitleRes;
                if (titleRes == 0) {
                    titleRes = header.titleRes;
                    shortTitleRes = 0;
                }
                startWithFragment(header.fragment, header.fragmentArguments, null, 0,
                        titleRes, shortTitleRes);
            } else {
                switchToHeader(header);
            }
        } else if (header.intent != null) {
            startActivity(header.intent);
        }
    }

private void switchToHeaderInner(String fragmentName, Bundle args, int direction) {
        getFragmentManager().popBackStack(BACK_STACK_PREFS,
                FragmentManager.POP_BACK_STACK_INCLUSIVE);
        if (!isValidFragment(fragmentName)) {
            throw new IllegalArgumentException("Invalid fragment for this activity: "
                    + fragmentName);
        }
        Fragment f = Fragment.instantiate(this, fragmentName, args);
        FragmentTransaction transaction = getFragmentManager().beginTransaction();
        transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
        transaction.replace(com.android.internal.R.id.prefs, f);
        transaction.commitAllowingStateLoss();
    }

startActivity(new Intent( android.provider.Settings.ACTION_WIRELESS_SETTINGS)); 

@Override
	public void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		addPreferencesFromResource(R.xml.wifi_preference);
	}

<?
xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <CheckBoxPreference
        android:key="isopen"
        android:title="wifi"
        android:defaultValue="true"/>
    <ListPreference
        android:key="list"
        android:title="声音大小"
        android:entries="@array/keys"
        android:entryValues="@array/values"/>
    <Preference
        android:key="click"
        android:title="单独的"
        />

</PreferenceScreen>

<PreferenceCategory >
        <cn.com.demo.ota.MyButtonPreference 
            android:key="start_install"
            android:title="@string/update_install"/>
    </PreferenceCategory>

 /**
     * {@inheritDoc}
     */
    public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen,
            Preference preference) {
        if (preference.getFragment() != null &&
                getActivity() instanceof OnPreferenceStartFragmentCallback) {
            return ((OnPreferenceStartFragmentCallback)getActivity()).onPreferenceStartFragment(
                    this, preference);
        }
        return false;
    }

update_more = (Preference)findPreference("update_more");<span style="font-size:18px;"><span style="font-size:18px;"><span style="font-size:18px;">

</span></span></span><pre name="code" class="java">update_more.setOnPreferenceClickListener(new OnPreferenceClickListener() {
				
				@Override
				public boolean onPreferenceClick(Preference preference) {
					
				}
			});

/**
     * Populate the activity with the top-level headers.
     */
    @Override
    public void onBuildHeaders(List<Header> headers) {
        loadHeadersFromResource(R.xml.iradar_settings_headers, headers);
        updateHeaderList(headers);
    }