问题
新增和编辑APN都是使用ApnEditorActivity，但是进入的方式不同，如果APN做成插件的话，点击添加按钮的时候会提示“选择要使用的应用”，因为Settings本身也有这个界面被安装进去了 。
- 新增功能通过Intent.ACTION_INSERT跳转界面
- 编辑功能通过Intent.ACTION_EDIT跳转界面
参考解决方案
通过优先级设置(<intent-filter android:priority="100">)并不能解决“选择要使用的应用”弹窗的问题，只能在AndroidManifest.xml移除Settings中对ApnEditorActivity的定义。
<!--<activity android:name="Settings$ApnEditorActivity"android:configChanges="orientation|keyboardHidden|screenSize"android:exported="true"android:label="@string/apn_edit"><intent-filter><action android:name="android.intent.action.VIEW" /><action android:name="android.intent.action.EDIT" /><category android:name="android.intent.category.DEFAULT" /><data android:mimeType="vnd.android.cursor.item/telephony-carrier" /></intent-filter><intent-filter><action android:name="android.intent.action.INSERT" /><category android:name="android.intent.category.DEFAULT" /><data android:mimeType="vnd.android.cursor.dir/telephony-carrier" /></intent-filter><meta-data android:name="com.android.settings.FRAGMENT_CLASS"android:value="com.android.settings.network.apn.ApnEditor" /><meta-data android:name="com.android.settings.HIGHLIGHT_MENU_KEY"android:value="@string/menu_key_network"/></activity>-->代码分析
新增APN
在ApnSettings中创建菜单，添加对应key=MENU_NEW，当菜单选择时执行addNewApn从而Intent.ACTION_INSERT
ApnSettings.java - OpenGrok cross reference for /packages/apps/Settings/src/com/android/settings/network/apn/ApnSettings.java
/** Handle each different apn setting. */
public class ApnSettings extends RestrictedSettingsFragmentimplements Preference.OnPreferenceChangeListener {static final String TAG = "ApnSettings";public static final String EXTRA_POSITION = "position";private static final int MENU_NEW = Menu.FIRST;private static final int MENU_RESTORE = Menu.FIRST + 1;//APN设置的菜单@Overridepublic void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {if (!mUnavailable) {if (mAllowAddingApns) {menu.add(0, MENU_NEW, 0,//新建getResources().getString(R.string.menu_new)).setIcon(R.drawable.ic_add_24dp).setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);}menu.add(0, MENU_RESTORE, 0,//重置getResources().getString(R.string.menu_restore)).setIcon(android.R.drawable.ic_menu_upload);}super.onCreateOptionsMenu(menu, inflater);}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {switch (item.getItemId()) {case MENU_NEW:addNewApn();return true;case MENU_RESTORE:restoreDefaultApn();return true;}return super.onOptionsItemSelected(item);}private void addNewApn() {final Intent intent = new Intent(Intent.ACTION_INSERT, Telephony.Carriers.CONTENT_URI);final int subId = mSubscriptionInfo != null ? mSubscriptionInfo.getSubscriptionId(): SubscriptionManager.INVALID_SUBSCRIPTION_ID;intent.putExtra(SUB_ID, subId);intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);if (!TextUtils.isEmpty(mMvnoType) && !TextUtils.isEmpty(mMvnoMatchData)) {intent.putExtra(MVNO_TYPE, mMvnoType);intent.putExtra(MVNO_MATCH_DATA, mMvnoMatchData);}startActivity(intent);}}编辑APN
在ApnSettings中apn_list添加了ApnPreference，将每个APN加载到APN列表中，而ApnPreference会相应点击事件，触发APN编辑功能，进入APN详情页。
ApnPreference.java - OpenGrok cross reference for /packages/apps/Settings/src/com/android/settings/network/apn/ApnPreference.java
/*** Preference of APN UI entry*/
public class ApnPreference extends Preference implements CompoundButton.OnCheckedChangeListener,View.OnClickListener {private static final String TAG = "ApnPreference";private int mSubId = SubscriptionManager.INVALID_SUBSCRIPTION_ID;@Overridepublic void onClick(View layoutView) {super.onClick();final Context context = getContext();final int pos = Integer.parseInt(getKey());if (context == null) {Log.w(TAG, "No context available for pos=" + pos);return;}if (mHideDetails) {Toast.makeText(context, context.getString(R.string.cannot_change_apn_toast), Toast.LENGTH_LONG).show();return;}//APN对应的数据库信息final Uri url = ContentUris.withAppendedId(Telephony.Carriers.CONTENT_URI, pos);final Intent editIntent = new Intent(Intent.ACTION_EDIT, url);editIntent.putExtra(ApnSettings.SUB_ID, mSubId);editIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);context.startActivity(editIntent);}