+++ /dev/null
-/*
- * Copyright (C) 2011 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 android.support.v2.content;
-
-import android.content.Context;
-import android.database.ContentObserver;
-import android.os.Handler;
-import android.support.v2.util.DebugUtils;
-
-import java.io.FileDescriptor;
-import java.io.PrintWriter;
-
-/**
- * Static library support version of the framework's {@link android.content.Loader}.
- * Used to write apps that run on platforms prior to Android 3.0. When running
- * on Android 3.0 or above, this implementation is still used; it does not try
- * to switch to the framework's implementation. See the framework SDK
- * documentation for a class overview.
- */
-public class Loader<D> {
- int mId;
- OnLoadCompleteListener<D> mListener;
- Context mContext;
- boolean mStarted = false;
- boolean mAbandoned = false;
- boolean mReset = true;
- boolean mContentChanged = false;
-
- public final class ForceLoadContentObserver extends ContentObserver {
- public ForceLoadContentObserver() {
- super(new Handler());
- }
-
- @Override
- public boolean deliverSelfNotifications() {
- return true;
- }
-
- @Override
- public void onChange(boolean selfChange) {
- onContentChanged();
- }
- }
-
- public interface OnLoadCompleteListener<D> {
- /**
- * Called on the thread that created the Loader when the load is complete.
- *
- * @param loader the loader that completed the load
- * @param data the result of the load
- */
- public void onLoadComplete(Loader<D> loader, D data);
- }
-
- /**
- * Stores away the application context associated with context. Since Loaders can be used
- * across multiple activities it's dangerous to store the context directly.
- *
- * @param context used to retrieve the application context.
- */
- public Loader(Context context) {
- mContext = context.getApplicationContext();
- }
-
- /**
- * Sends the result of the load to the registered listener. Should only be called by subclasses.
- *
- * Must be called from the process's main thread.
- *
- * @param data the result of the load
- */
- public void deliverResult(D data) {
- if (mListener != null) {
- mListener.onLoadComplete(this, data);
- }
- }
-
- /**
- * @return an application context retrieved from the Context passed to the constructor.
- */
- public Context getContext() {
- return mContext;
- }
-
- /**
- * @return the ID of this loader
- */
- public int getId() {
- return mId;
- }
-
- /**
- * Registers a class that will receive callbacks when a load is complete.
- * The callback will be called on the process's main thread so it's safe to
- * pass the results to widgets.
- *
- * <p>Must be called from the process's main thread.
- */
- public void registerListener(int id, OnLoadCompleteListener<D> listener) {
- if (mListener != null) {
- throw new IllegalStateException("There is already a listener registered");
- }
- mListener = listener;
- mId = id;
- }
-
- /**
- * Remove a listener that was previously added with {@link #registerListener}.
- *
- * Must be called from the process's main thread.
- */
- public void unregisterListener(OnLoadCompleteListener<D> listener) {
- if (mListener == null) {
- throw new IllegalStateException("No listener register");
- }
- if (mListener != listener) {
- throw new IllegalArgumentException("Attempting to unregister the wrong listener");
- }
- mListener = null;
- }
-
- /**
- * Return whether this load has been started. That is, its {@link #startLoading()}
- * has been called and no calls to {@link #stopLoading()} or
- * {@link #reset()} have yet been made.
- */
- public boolean isStarted() {
- return mStarted;
- }
-
- /**
- * Return whether this loader has been abandoned. In this state, the
- * loader <em>must not</em> report any new data, and <em>must</em> keep
- * its last reported data valid until it is finally reset.
- */
- public boolean isAbandoned() {
- return mAbandoned;
- }
-
- /**
- * Return whether this load has been reset. That is, either the loader
- * has not yet been started for the first time, or its {@link #reset()}
- * has been called.
- */
- public boolean isReset() {
- return mReset;
- }
-
- /**
- * Starts an asynchronous load of the Loader's data. When the result
- * is ready the callbacks will be called on the process's main thread.
- * If a previous load has been completed and is still valid
- * the result may be passed to the callbacks immediately.
- * The loader will monitor the source of
- * the data set and may deliver future callbacks if the source changes.
- * Calling {@link #stopLoading} will stop the delivery of callbacks.
- *
- * <p>This updates the Loader's internal state so that
- * {@link #isStarted()} and {@link #isReset()} will return the correct
- * values, and then calls the implementation's {@link #onStartLoading()}.
- *
- * <p>Must be called from the process's main thread.
- */
- public final void startLoading() {
- mStarted = true;
- mReset = false;
- mAbandoned = false;
- onStartLoading();
- }
-
- /**
- * Subclasses must implement this to take care of loading their data,
- * as per {@link #startLoading()}. This is not called by clients directly,
- * but as a result of a call to {@link #startLoading()}.
- */
- protected void onStartLoading() {
- }
-
- /**
- * Force an asynchronous load. Unlike {@link #startLoading()} this will ignore a previously
- * loaded data set and load a new one. This simply calls through to the
- * implementation's {@link #onForceLoad()}. You generally should only call this
- * when the loader is started -- that is, {@link #isStarted()} returns true.
- *
- * <p>Must be called from the process's main thread.
- */
- public void forceLoad() {
- onForceLoad();
- }
-
- /**
- * Subclasses must implement this to take care of requests to {@link #forceLoad()}.
- * This will always be called from the process's main thread.
- */
- protected void onForceLoad() {
- }
-
- /**
- * Stops delivery of updates until the next time {@link #startLoading()} is called.
- * Implementations should <em>not</em> invalidate their data at this point --
- * clients are still free to use the last data the loader reported. They will,
- * however, typically stop reporting new data if the data changes; they can
- * still monitor for changes, but must not report them to the client until and
- * if {@link #startLoading()} is later called.
- *
- * <p>This updates the Loader's internal state so that
- * {@link #isStarted()} will return the correct
- * value, and then calls the implementation's {@link #onStopLoading()}.
- *
- * <p>Must be called from the process's main thread.
- */
- public void stopLoading() {
- mStarted = false;
- onStopLoading();
- }
-
- /**
- * Subclasses must implement this to take care of stopping their loader,
- * as per {@link #stopLoading()}. This is not called by clients directly,
- * but as a result of a call to {@link #stopLoading()}.
- * This will always be called from the process's main thread.
- */
- protected void onStopLoading() {
- }
-
- /**
- * Tell the Loader that it is being abandoned. This is called prior
- * to {@link #reset} to have it retain its current data but not report
- * any new data.
- */
- public void abandon() {
- mAbandoned = true;
- onAbandon();
- }
-
- /**
- * Subclasses implement this to take care of being abandoned. This is
- * an optional intermediate state prior to {@link #onReset()} -- it means that
- * the client is no longer interested in any new data from the loader,
- * so the loader must not report any further updates. However, the
- * loader <em>must</em> keep its last reported data valid until the final
- * {@link #onReset()} happens. You can retrieve the current abandoned
- * state with {@link #isAbandoned}.
- */
- protected void onAbandon() {
- }
-
- /**
- * Resets the state of the Loader. The Loader should at this point free
- * all of its resources, since it may never be called again; however, its
- * {@link #startLoading()} may later be called at which point it must be
- * able to start running again.
- *
- * <p>This updates the Loader's internal state so that
- * {@link #isStarted()} and {@link #isReset()} will return the correct
- * values, and then calls the implementation's {@link #onReset()}.
- *
- * <p>Must be called from the process's main thread.
- */
- public void reset() {
- onReset();
- mReset = true;
- mStarted = false;
- mAbandoned = false;
- mContentChanged = false;
- }
-
- /**
- * Subclasses must implement this to take care of resetting their loader,
- * as per {@link #reset()}. This is not called by clients directly,
- * but as a result of a call to {@link #reset()}.
- * This will always be called from the process's main thread.
- */
- protected void onReset() {
- }
-
- /**
- * Take the current flag indicating whether the loader's content had
- * changed while it was stopped. If it had, true is returned and the
- * flag is cleared.
- */
- public boolean takeContentChanged() {
- boolean res = mContentChanged;
- mContentChanged = false;
- return res;
- }
-
- /**
- * Called when {@link ForceLoadContentObserver} detects a change. The
- * default implementation checks to see if the loader is currently started;
- * if so, it simply calls {@link #forceLoad()}; otherwise, it sets a flag
- * so that {@link #takeContentChanged()} returns true.
- *
- * <p>Must be called from the process's main thread.
- */
- public void onContentChanged() {
- if (mStarted) {
- forceLoad();
- } else {
- // This loader has been stopped, so we don't want to load
- // new data right now... but keep track of it changing to
- // refresh later if we start again.
- mContentChanged = true;
- }
- }
-
- /**
- * For debugging, converts an instance of the Loader's data class to
- * a string that can be printed. Must handle a null data.
- */
- public String dataToString(D data) {
- StringBuilder sb = new StringBuilder(64);
- DebugUtils.buildShortClassTag(data, sb);
- sb.append("}");
- return sb.toString();
- }
-
- @Override
- public String toString() {
- StringBuilder sb = new StringBuilder(64);
- DebugUtils.buildShortClassTag(this, sb);
- sb.append(" id=");
- sb.append(mId);
- sb.append("}");
- return sb.toString();
- }
-
- /**
- * Print the Loader's state into the given stream.
- *
- * @param prefix Text to print at the front of each line.
- * @param fd The raw file descriptor that the dump is being sent to.
- * @param writer A PrintWriter to which the dump is to be set.
- * @param args Additional arguments to the dump request.
- */
- public void dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args) {
- writer.print(prefix); writer.print("mId="); writer.print(mId);
- writer.print(" mListener="); writer.println(mListener);
- writer.print(prefix); writer.print("mStarted="); writer.print(mStarted);
- writer.print(" mContentChanged="); writer.print(mContentChanged);
- writer.print(" mAbandoned="); writer.print(mAbandoned);
- writer.print(" mReset="); writer.println(mReset);
- }
-}
\ No newline at end of file
notaz.gp2x.de / android_pandora.git / blobdiff