Java tutorial
package android.support.v4.app; import java.lang.reflect.Constructor; import java.lang.reflect.Field; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; import java.lang.reflect.Proxy; import android.app.Activity; import android.content.Context; import android.content.Intent; import android.preference.Preference; import android.preference.PreferenceManager; import android.preference.PreferenceScreen; import android.util.Log; public class PreferenceManagerCompat { protected static final String TAG = PreferenceManagerCompat.class.getSimpleName(); /** * Interface definition for a callback to be invoked when a * {@link Preference} in the hierarchy rooted at this {@link PreferenceScreen} is * clicked. */ interface OnPreferenceTreeClickListener { /** * Called when a preference in the tree rooted at this * {@link PreferenceScreen} has been clicked. * * @param preferenceScreen The {@link PreferenceScreen} that the * preference is located in. * @param preference The preference that was clicked. * @return Whether the click was handled. */ boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen, Preference preference); } static PreferenceManager newInstance(Activity activity, int firstRequestCode) { try { Constructor<PreferenceManager> c = PreferenceManager.class.getDeclaredConstructor(Activity.class, int.class); c.setAccessible(true); return c.newInstance(activity, firstRequestCode); } catch (Exception e) { Log.w(TAG, "Couldn't call constructor PreferenceManager by reflection", e); } return null; } /** * Sets the callback to be invoked when a {@link Preference} in the * hierarchy rooted at this {@link PreferenceManager} is clicked. * * @param listener The callback to be invoked. */ static void setOnPreferenceTreeClickListener(PreferenceManager manager, final OnPreferenceTreeClickListener listener) { try { Field onPreferenceTreeClickListener = PreferenceManager.class .getDeclaredField("mOnPreferenceTreeClickListener"); onPreferenceTreeClickListener.setAccessible(true); if (listener != null) { Object proxy = Proxy.newProxyInstance(onPreferenceTreeClickListener.getType().getClassLoader(), new Class[] { onPreferenceTreeClickListener.getType() }, new InvocationHandler() { public Object invoke(Object proxy, Method method, Object[] args) { if (method.getName().equals("onPreferenceTreeClick")) { return Boolean.valueOf(listener.onPreferenceTreeClick( (PreferenceScreen) args[0], (Preference) args[1])); } else { return null; } } }); onPreferenceTreeClickListener.set(manager, proxy); } else { onPreferenceTreeClickListener.set(manager, null); } } catch (Exception e) { Log.w(TAG, "Couldn't set PreferenceManager.mOnPreferenceTreeClickListener by reflection", e); } } /** * Inflates a preference hierarchy from the preference hierarchies of * {@link Activity Activities} that match the given {@link Intent}. An * {@link Activity} defines its preference hierarchy with meta-data using * the {@link #METADATA_KEY_PREFERENCES} key. * <p> * If a preference hierarchy is given, the new preference hierarchies will * be merged in. * * @param queryIntent The intent to match activities. * @param rootPreferences Optional existing hierarchy to merge the new * hierarchies into. * @return The root hierarchy (if one was not provided, the new hierarchy's * root). */ static PreferenceScreen inflateFromIntent(PreferenceManager manager, Intent intent, PreferenceScreen screen) { try { Method m = PreferenceManager.class.getDeclaredMethod("inflateFromIntent", Intent.class, PreferenceScreen.class); m.setAccessible(true); PreferenceScreen prefScreen = (PreferenceScreen) m.invoke(manager, intent, screen); return prefScreen; } catch (Exception e) { Log.w(TAG, "Couldn't call PreferenceManager.inflateFromIntent by reflection", e); } return null; } /** * Inflates a preference hierarchy from XML. If a preference hierarchy is * given, the new preference hierarchies will be merged in. * * @param context The context of the resource. * @param resId The resource ID of the XML to inflate. * @param rootPreferences Optional existing hierarchy to merge the new * hierarchies into. * @return The root hierarchy (if one was not provided, the new hierarchy's * root). * @hide */ static PreferenceScreen inflateFromResource(PreferenceManager manager, Activity activity, int resId, PreferenceScreen screen) { try { Method m = PreferenceManager.class.getDeclaredMethod("inflateFromResource", Context.class, int.class, PreferenceScreen.class); m.setAccessible(true); PreferenceScreen prefScreen = (PreferenceScreen) m.invoke(manager, activity, resId, screen); return prefScreen; } catch (Exception e) { Log.w(TAG, "Couldn't call PreferenceManager.inflateFromResource by reflection", e); } return null; } /** * Returns the root of the preference hierarchy managed by this class. * * @return The {@link PreferenceScreen} object that is at the root of the hierarchy. */ static PreferenceScreen getPreferenceScreen(PreferenceManager manager) { try { Method m = PreferenceManager.class.getDeclaredMethod("getPreferenceScreen"); m.setAccessible(true); return (PreferenceScreen) m.invoke(manager); } catch (Exception e) { Log.w(TAG, "Couldn't call PreferenceManager.getPreferenceScreen by reflection", e); } return null; } /** * Called by the {@link PreferenceManager} to dispatch a subactivity result. */ static void dispatchActivityResult(PreferenceManager manager, int requestCode, int resultCode, Intent data) { try { Method m = PreferenceManager.class.getDeclaredMethod("dispatchActivityResult", int.class, int.class, Intent.class); m.setAccessible(true); m.invoke(manager, requestCode, resultCode, data); } catch (Exception e) { Log.w(TAG, "Couldn't call PreferenceManager.dispatchActivityResult by reflection", e); } } /** * Called by the {@link PreferenceManager} to dispatch the activity stop * event. */ static void dispatchActivityStop(PreferenceManager manager) { try { Method m = PreferenceManager.class.getDeclaredMethod("dispatchActivityStop"); m.setAccessible(true); m.invoke(manager); } catch (Exception e) { Log.w(TAG, "Couldn't call PreferenceManager.dispatchActivityStop by reflection", e); } } /** * Called by the {@link PreferenceManager} to dispatch the activity destroy * event. */ static void dispatchActivityDestroy(PreferenceManager manager) { try { Method m = PreferenceManager.class.getDeclaredMethod("dispatchActivityDestroy"); m.setAccessible(true); m.invoke(manager); } catch (Exception e) { Log.w(TAG, "Couldn't call PreferenceManager.dispatchActivityDestroy by reflection", e); } } /** * Sets the root of the preference hierarchy. * * @param preferenceScreen The root {@link PreferenceScreen} of the preference hierarchy. * @return Whether the {@link PreferenceScreen} given is different than the previous. */ static boolean setPreferences(PreferenceManager manager, PreferenceScreen screen) { try { Method m = PreferenceManager.class.getDeclaredMethod("setPreferences", PreferenceScreen.class); m.setAccessible(true); return ((Boolean) m.invoke(manager, screen)); } catch (Exception e) { Log.w(TAG, "Couldn't call PreferenceManager.setPreferences by reflection", e); } return false; } }