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/*
* 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.view;
import dalvik.system.CloseGuard;
import android.os.Looper;
import android.os.MessageQueue;
import android.util.Log;
import android.util.SparseIntArray;
/**
* Provides a low-level mechanism for an application to receive input events.
* @hide
*/
public abstract class InputEventReceiver {
private static final String TAG = "InputEventReceiver";
private final CloseGuard mCloseGuard = CloseGuard.get();
private int mReceiverPtr;
// We keep references to the input channel and message queue objects here so that
// they are not GC'd while the native peer of the receiver is using them.
private InputChannel mInputChannel;
private MessageQueue mMessageQueue;
// Map from InputEvent sequence numbers to dispatcher sequence numbers.
private final SparseIntArray mSeqMap = new SparseIntArray();
private static native int nativeInit(InputEventReceiver receiver,
InputChannel inputChannel, MessageQueue messageQueue);
private static native void nativeDispose(int receiverPtr);
private static native void nativeFinishInputEvent(int receiverPtr, int seq, boolean handled);
private static native void nativeConsumeBatchedInputEvents(int receiverPtr);
/**
* Creates an input event receiver bound to the specified input channel.
*
* @param inputChannel The input channel.
* @param looper The looper to use when invoking callbacks.
*/
public InputEventReceiver(InputChannel inputChannel, Looper looper) {
if (inputChannel == null) {
throw new IllegalArgumentException("inputChannel must not be null");
}
if (looper == null) {
throw new IllegalArgumentException("looper must not be null");
}
mInputChannel = inputChannel;
mMessageQueue = looper.getQueue();
mReceiverPtr = nativeInit(this, inputChannel, mMessageQueue);
mCloseGuard.open("dispose");
}
@Override
protected void finalize() throws Throwable {
try {
dispose();
} finally {
super.finalize();
}
}
/**
* Disposes the receiver.
*/
public void dispose() {
if (mCloseGuard != null) {
mCloseGuard.close();
}
if (mReceiverPtr != 0) {
nativeDispose(mReceiverPtr);
mReceiverPtr = 0;
}
mInputChannel = null;
mMessageQueue = null;
}
/**
* Called when an input event is received.
* The recipient should process the input event and then call {@link #finishInputEvent}
* to indicate whether the event was handled. No new input events will be received
* until {@link #finishInputEvent} is called.
*
* @param event The input event that was received.
*/
public void onInputEvent(InputEvent event) {
finishInputEvent(event, false);
}
/**
* Called when a batched input event is pending.
*
* The batched input event will continue to accumulate additional movement
* samples until the recipient calls {@link #consumeBatchedInputEvents} or
* an event is received that ends the batch and causes it to be consumed
* immediately (such as a pointer up event).
*/
public void onBatchedInputEventPending() {
consumeBatchedInputEvents();
}
/**
* Finishes an input event and indicates whether it was handled.
* Must be called on the same Looper thread to which the receiver is attached.
*
* @param event The input event that was finished.
* @param handled True if the event was handled.
*/
public final void finishInputEvent(InputEvent event, boolean handled) {
if (event == null) {
throw new IllegalArgumentException("event must not be null");
}
if (mReceiverPtr == 0) {
Log.w(TAG, "Attempted to finish an input event but the input event "
+ "receiver has already been disposed.");
} else {
int index = mSeqMap.indexOfKey(event.getSequenceNumber());
if (index < 0) {
Log.w(TAG, "Attempted to finish an input event that is not in progress.");
} else {
int seq = mSeqMap.valueAt(index);
mSeqMap.removeAt(index);
nativeFinishInputEvent(mReceiverPtr, seq, handled);
}
}
event.recycleIfNeededAfterDispatch();
}
/**
* Consumes all pending batched input events.
* Must be called on the same Looper thread to which the receiver is attached.
*
* This method forces all batched input events to be delivered immediately.
* Should be called just before animating or drawing a new frame in the UI.
*/
public final void consumeBatchedInputEvents() {
if (mReceiverPtr == 0) {
Log.w(TAG, "Attempted to consume batched input events but the input event "
+ "receiver has already been disposed.");
} else {
nativeConsumeBatchedInputEvents(mReceiverPtr);
}
}
// Called from native code.
@SuppressWarnings("unused")
private void dispatchInputEvent(int seq, InputEvent event) {
mSeqMap.put(event.getSequenceNumber(), seq);
onInputEvent(event);
}
// Called from native code.
@SuppressWarnings("unused")
private void dispatchBatchedInputEventPending() {
onBatchedInputEventPending();
}
public static interface Factory {
public InputEventReceiver createInputEventReceiver(
InputChannel inputChannel, Looper looper);
}
}
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