Java tutorial
/* * Copyright (C) 2010 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package me.piebridge.android.preference; import java.lang.reflect.Constructor; import java.lang.reflect.InvocationHandler; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.lang.reflect.Proxy; import org.xmlpull.v1.XmlPullParser; import android.annotation.SuppressLint; import android.app.Activity; import android.support.v4.app.Fragment; import android.content.Context; import android.content.Intent; import android.content.SharedPreferences; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.preference.Preference; import android.preference.PreferenceGroup; import android.preference.PreferenceManager; import android.preference.PreferenceScreen; import android.util.Base64; import android.view.KeyEvent; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.View.OnKeyListener; import android.widget.ListView; /** * Shows a hierarchy of {@link Preference} objects as * lists. These preferences will * automatically save to {@link SharedPreferences} as the user interacts with * them. To retrieve an instance of {@link SharedPreferences} that the * preference hierarchy in this fragment will use, call * {@link PreferenceManager#getDefaultSharedPreferences(android.content.Context)} * with a context in the same package as this fragment. * <p> * Furthermore, the preferences shown will follow the visual style of system * preferences. It is easy to create a hierarchy of preferences (that can be * shown on multiple screens) via XML. For these reasons, it is recommended to * use this fragment (as a superclass) to deal with preferences in applications. * <p> * A {@link PreferenceScreen} object should be at the top of the preference * hierarchy. Furthermore, subsequent {@link PreferenceScreen} in the hierarchy * denote a screen break--that is the preferences contained within subsequent * {@link PreferenceScreen} should be shown on another screen. The preference * framework handles showing these other screens from the preference hierarchy. * <p> * The preference hierarchy can be formed in multiple ways: * <li> From an XML file specifying the hierarchy * <li> From different {@link Activity Activities} that each specify its own * preferences in an XML file via {@link Activity} meta-data * <li> From an object hierarchy rooted with {@link PreferenceScreen} * <p> * To inflate from XML, use the {@link #addPreferencesFromResource(int)}. The * root element should be a {@link PreferenceScreen}. Subsequent elements can point * to actual {@link Preference} subclasses. As mentioned above, subsequent * {@link PreferenceScreen} in the hierarchy will result in the screen break. * <p> * To specify an {@link Intent} to query {@link Activity Activities} that each * have preferences, use {@link #addPreferencesFromIntent}. Each * {@link Activity} can specify meta-data in the manifest (via the key * {@link PreferenceManager#METADATA_KEY_PREFERENCES}) that points to an XML * resource. These XML resources will be inflated into a single preference * hierarchy and shown by this fragment. * <p> * To specify an object hierarchy rooted with {@link PreferenceScreen}, use * {@link #setPreferenceScreen(PreferenceScreen)}. * <p> * As a convenience, this fragment implements a click listener for any * preference in the current hierarchy, see * {@link #onPreferenceTreeClick(PreferenceScreen, Preference)}. * * <div class="special reference"> * <h3>Developer Guides</h3> * <p>For information about using {@code PreferenceFragment}, * read the <a href="{@docRoot}guide/topics/ui/settings.html">Settings</a> * guide.</p> * </div> * * <a name="SampleCode"></a> * <h3>Sample Code</h3> * * <p>The following sample code shows a simple preference fragment that is * populated from a resource. The resource it loads is:</p> * * {@sample development/samples/ApiDemos/res/xml/preferences.xml preferences} * * <p>The fragment implementation itself simply populates the preferences * when created. Note that the preferences framework takes care of loading * the current values out of the app preferences and writing them when changed:</p> * * {@sample development/samples/ApiDemos/src/com/example/android/apis/preference/FragmentPreferences.java * fragment} * * @see Preference * @see PreferenceScreen */ public abstract class PreferenceFragment extends Fragment { private static final String PREFERENCES_TAG = "android:preferences"; private PreferenceManager mPreferenceManager; private ListView mList; private boolean mHavePrefs; private boolean mInitDone; /** * The starting request code given out to preference framework. */ private static final int FIRST_REQUEST_CODE = 100; private static final int MSG_BIND_PREFERENCES = 1; @SuppressLint("HandlerLeak") private Handler mHandler = new Handler() { @Override public void handleMessage(Message msg) { switch (msg.what) { case MSG_BIND_PREFERENCES: bindPreferences(); break; } } }; final private Runnable mRequestFocus = new Runnable() { public void run() { mList.focusableViewAvailable(mList); } }; /** * Interface that PreferenceFragment's containing activity should * implement to be able to process preference items that wish to * switch to a new fragment. */ public interface OnPreferenceStartFragmentCallback { /** * Called when the user has clicked on a Preference that has * a fragment class name associated with it. The implementation * to should instantiate and switch to an instance of the given * fragment. */ boolean onPreferenceStartFragment(PreferenceFragment caller, Preference pref); } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // FIXME: mPreferenceManager = new PreferenceManager(getActivity(), FIRST_REQUEST_CODE); mPreferenceManager = callConstructor(PreferenceManager.class, new Class[] { Activity.class, int.class }, new Object[] { getActivity(), FIRST_REQUEST_CODE }); // FIXME: mPreferenceManager.setFragment(this); } public static final String LAYOUT = "AwAIABgEAAABABwA0AEAABQAAAAAAAAAAAEAAGwAAAAAAAAAAAAAAA4AAAAeAAAALQAAADoAAAA/" + "AAAATwAAAFwAAABsAAAAegAAAIkAAACaAAAAqgAAAL4AAADPAAAA8gAAAPwAAAApAQAALAEAAEoB" + "AAALC29yaWVudGF0aW9uAA0NbGF5b3V0X2hlaWdodAAMDGxheW91dF93aWR0aAAKCmJhY2tncm91" + "bmQAAgJpZAANDWxheW91dF93ZWlnaHQACgpwYWRkaW5nVG9wAA0NcGFkZGluZ0JvdHRvbQALC3Bh" + "ZGRpbmdMZWZ0AAwMcGFkZGluZ1JpZ2h0AA4Oc2Nyb2xsYmFyU3R5bGUADQ1jbGlwVG9QYWRkaW5n" + "ABERZHJhd1NlbGVjdG9yT25Ub3AADg5jYWNoZUNvbG9ySGludAAgIHNjcm9sbGJhckFsd2F5c0Ry" + "YXdWZXJ0aWNhbFRyYWNrAAcHYW5kcm9pZAAqKmh0dHA6Ly9zY2hlbWFzLmFuZHJvaWQuY29tL2Fw" + "ay9yZXMvYW5kcm9pZAAAAAAbG2FuZHJvaWQud2lkZ2V0LkxpbmVhckxheW91dAAXF2FuZHJvaWQu" + "d2lkZ2V0Lkxpc3RWaWV3AIABCABEAAAAxAABAfUAAQH0AAEB1AABAdAAAQGBAQEB1wABAdkAAQHW" + "AAEB2AABAX8AAQHrAAEB/AABAQEBAQFpAAEBAAEQABgAAAACAAAA/////w8AAAAQAAAAAgEQAHQA" + "AAACAAAA//////////8SAAAAFAAUAAQAAAAAAAAAEAAAAAAAAAD/////CAAAEAEAAAAQAAAAAwAA" + "AP////8IAAABDQAGARAAAAACAAAA/////wgAABD/////EAAAAAEAAAD/////CAAAEP////8CARAA" + "KAEAAAgAAAD//////////xMAAAAUABQADQAAAAAAAAAQAAAADgAAAP////8IAAAS/////xAAAAAK" + "AAAA/////wgAABEAAAACEAAAAAQAAAD/////CAAAAQoAAgEQAAAACAAAAP////8IAAAFARAAABAA" + "AAAGAAAA/////wgAAAUBAAAAEAAAAAkAAAD/////CAAABQEQAAAQAAAABwAAAP////8IAAAFAQAA" + "ABAAAAALAAAA/////wgAABIAAAAAEAAAAAIAAAD/////CAAAEP////8QAAAAAQAAAP////8IAAAF" + "AAAAABAAAAAMAAAA/////wgAABIAAAAAEAAAAA0AAAD/////CAAAAQ0ABgEQAAAABQAAAP////8I" + "AAAEAACAPwMBEAAYAAAAFAAAAP//////////EwAAAAMBEAAYAAAAFgAAAP//////////EgAAAAEB" + "EAAYAAAAFgAAAP////8PAAAAEAAAAA=="; /** * return XmlPullParser * @param xml compiled XML encoded in base64 * @return XmlPullParser */ public static XmlPullParser getParser(String xml) { try { byte[] data = Base64.decode(xml, Base64.DEFAULT); // XmlBlock block = new XmlBlock(LAYOUT.getBytes("UTF-8")); Class<?> clazz = Class.forName("android.content.res.XmlBlock"); Constructor<?> constructor = clazz.getDeclaredConstructor(byte[].class); constructor.setAccessible(true); Object block = constructor.newInstance(data); // XmlPullParser parser = block.newParser(); Method method = clazz.getDeclaredMethod("newParser"); method.setAccessible(true); return (XmlPullParser) method.invoke(block); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (NoSuchMethodException e) { e.printStackTrace(); } catch (IllegalArgumentException e) { e.printStackTrace(); } catch (java.lang.InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } return null; } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(getParser(LAYOUT), container, false); } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); if (mHavePrefs) { bindPreferences(); } mInitDone = true; if (savedInstanceState != null) { Bundle container = savedInstanceState.getBundle(PREFERENCES_TAG); if (container != null) { final PreferenceScreen preferenceScreen = getPreferenceScreen(); if (preferenceScreen != null) { preferenceScreen.restoreHierarchyState(container); } } } } @Override public void onStart() { super.onStart(); // FIXME: mPreferenceManager.setOnPreferenceTreeClickListener(this); try { Class<?> clazz = Class.forName("android.preference.PreferenceManager$OnPreferenceTreeClickListener"); Object proxy = Proxy.newProxyInstance(clazz.getClassLoader(), new Class[] { clazz }, new InvocationHandler() { @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { if (method.getName().equals("onPreferenceTreeClick")) { return onPreferenceTreeClick((PreferenceScreen) args[0], (Preference) args[1]); } return null; } }); callVoidMethod(mPreferenceManager, "setOnPreferenceTreeClickListener", new Class[] { clazz }, new Object[] { proxy }); } catch (ClassNotFoundException e) { e.printStackTrace(); } } @Override public void onStop() { super.onStop(); // FIXME: mPreferenceManager.dispatchActivityStop(); callVoidMethod(mPreferenceManager, "dispatchActivityStop", null, null); // FIXME: mPreferenceManager.setOnPreferenceTreeClickListener(null); try { Class<?> clazz = Class.forName("android.preference.PreferenceManager$OnPreferenceTreeClickListener"); callVoidMethod(mPreferenceManager, "setOnPreferenceTreeClickListener", new Class[] { clazz }, new Object[] { null }); } catch (ClassNotFoundException e) { e.printStackTrace(); } } @Override public void onDestroyView() { mList = null; mHandler.removeCallbacks(mRequestFocus); mHandler.removeMessages(MSG_BIND_PREFERENCES); super.onDestroyView(); } @Override public void onDestroy() { super.onDestroy(); // FIXME: mPreferenceManager.dispatchActivityDestroy(); callVoidMethod(mPreferenceManager, "dispatchActivityDestroy", null, null); } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); final PreferenceScreen preferenceScreen = getPreferenceScreen(); if (preferenceScreen != null) { Bundle container = new Bundle(); preferenceScreen.saveHierarchyState(container); outState.putBundle(PREFERENCES_TAG, container); } } @Override public void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); // FIXME: mPreferenceManager.dispatchActivityResult(requestCode, resultCode, data); callVoidMethod(mPreferenceManager, "dispatchActivityResult", new Class[] { int.class, int.class, Intent.class }, new Object[] { requestCode, resultCode, data }); } /** * Returns the {@link PreferenceManager} used by this fragment. * @return The {@link PreferenceManager}. */ public PreferenceManager getPreferenceManager() { return mPreferenceManager; } /** * Sets the root of the preference hierarchy that this fragment is showing. * * @param preferenceScreen The root {@link PreferenceScreen} of the preference hierarchy. */ public void setPreferenceScreen(PreferenceScreen preferenceScreen) { // FIXME: if (mPreferenceManager.setPreferences(preferenceScreen) && preferenceScreen != null) { if (callReturnMethod(mPreferenceManager, "setPreferences", Boolean.class, new Class[] { PreferenceScreen.class }, new Object[] { preferenceScreen }) && preferenceScreen != null) { mHavePrefs = true; if (mInitDone) { postBindPreferences(); } } } /** * Gets the root of the preference hierarchy that this fragment is showing. * * @return The {@link PreferenceScreen} that is the root of the preference * hierarchy. */ public PreferenceScreen getPreferenceScreen() { // FIXME: return mPreferenceManager.getPreferenceScreen(); return callReturnMethod(mPreferenceManager, "getPreferenceScreen", PreferenceScreen.class, null, null); } /** * Adds preferences from activities that match the given {@link Intent}. * * @param intent The {@link Intent} to query activities. */ public void addPreferencesFromIntent(Intent intent) { requirePreferenceManager(); // FIXME: setPreferenceScreen(mPreferenceManager.inflateFromIntent(intent, getPreferenceScreen())); setPreferenceScreen(callReturnMethod(mPreferenceManager, "inflateFromIntent", PreferenceScreen.class, new Class[] { Intent.class, PreferenceScreen.class }, new Object[] { intent, getPreferenceScreen() })); } /** * Inflates the given XML resource and adds the preference hierarchy to the current * preference hierarchy. * * @param preferencesResId The XML resource ID to inflate. */ public void addPreferencesFromResource(int preferencesResId) { requirePreferenceManager(); // FIXME: setPreferenceScreen(mPreferenceManager.inflateFromResource(getActivity(), // preferencesResId, getPreferenceScreen())); setPreferenceScreen(callReturnMethod(mPreferenceManager, "inflateFromResource", PreferenceScreen.class, new Class[] { Context.class, int.class, PreferenceScreen.class }, new Object[] { getActivity(), preferencesResId, getPreferenceScreen() })); } /** * {@inheritDoc} */ public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen, Preference preference) { // FIXME: preference.getFragment() if (/*preference.getFragment() != null &&*/ getActivity() instanceof OnPreferenceStartFragmentCallback) { return ((OnPreferenceStartFragmentCallback) getActivity()).onPreferenceStartFragment(this, preference); } return false; } /** * Finds a {@link Preference} based on its key. * * @param key The key of the preference to retrieve. * @return The {@link Preference} with the key, or null. * @see PreferenceGroup#findPreference(CharSequence) */ public Preference findPreference(CharSequence key) { if (mPreferenceManager == null) { return null; } return mPreferenceManager.findPreference(key); } private void requirePreferenceManager() { if (mPreferenceManager == null) { throw new RuntimeException("This should be called after super.onCreate."); } } private void postBindPreferences() { if (mHandler.hasMessages(MSG_BIND_PREFERENCES)) return; mHandler.obtainMessage(MSG_BIND_PREFERENCES).sendToTarget(); } private void bindPreferences() { final PreferenceScreen preferenceScreen = getPreferenceScreen(); if (preferenceScreen != null) { preferenceScreen.bind(getListView()); } } /** @hide */ public ListView getListView() { ensureList(); return mList; } private void ensureList() { if (mList != null) { return; } View root = getView(); if (root == null) { throw new IllegalStateException("Content view not yet created"); } View rawListView = root.findViewById(android.R.id.list); if (!(rawListView instanceof ListView)) { throw new RuntimeException( "Content has view with id attribute 'android.R.id.list' " + "that is not a ListView class"); } mList = (ListView) rawListView; if (mList == null) { throw new RuntimeException( "Your content must have a ListView whose id attribute is " + "'android.R.id.list'"); } mList.setOnKeyListener(mListOnKeyListener); mHandler.post(mRequestFocus); } private OnKeyListener mListOnKeyListener = new OnKeyListener() { @Override public boolean onKey(View v, int keyCode, KeyEvent event) { Object selectedItem = mList.getSelectedItem(); if (selectedItem instanceof Preference) { View selectedView = mList.getSelectedView(); // FIXME : return ((Preference)selectedItem).onKey( // selectedView, keyCode, event); return callReturnMethod(selectedItem, "onKey", Boolean.class, new Class[] { View.class, int.class, KeyEvent.class }, new Object[] { selectedView, keyCode, event }); } return false; } }; public static void callVoidMethod(Object receiver, String methodName, Class<?>[] parameterTypes, Object[] args) { try { Method method = receiver.getClass().getDeclaredMethod(methodName, parameterTypes); method.setAccessible(true); method.invoke(receiver, args); } catch (NoSuchMethodException e) { e.printStackTrace(); } catch (IllegalArgumentException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } } @SuppressWarnings("unchecked") public static <T> T callReturnMethod(Object receiver, String methodName, Class<T> returnType, Class<?>[] parameterTypes, Object[] args) { try { Method method = receiver.getClass().getDeclaredMethod(methodName, parameterTypes); method.setAccessible(true); return (T) method.invoke(receiver, args); } catch (NoSuchMethodException e) { e.printStackTrace(); } catch (IllegalArgumentException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } if (Boolean.class.equals(returnType)) { return (T) Boolean.FALSE; } return null; } @SuppressWarnings("unchecked") public static <T> T callConstructor(Class<T> returnType, Class<?>[] parameterTypes, Object[] args) { try { Constructor<?> constructor = returnType.getDeclaredConstructor(parameterTypes); constructor.setAccessible(true); return (T) constructor.newInstance(args); } catch (NoSuchMethodException e) { e.printStackTrace(); } catch (IllegalArgumentException e) { e.printStackTrace(); } catch (java.lang.InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } return null; } }