Home | History | Annotate | Download | only in wm 
      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.server.wm;
     18 
     19 import static android.view.InputDevice.SOURCE_CLASS_POINTER;
     20 import static android.view.MotionEvent.ACTION_CANCEL;
     21 import static android.view.MotionEvent.ACTION_DOWN;
     22 import static android.view.MotionEvent.ACTION_MOVE;
     23 import static android.view.MotionEvent.ACTION_UP;
     24 import static android.view.MotionEvent.BUTTON_STYLUS_PRIMARY;
     25 import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_DRAG;
     26 import static com.android.server.wm.WindowManagerDebugConfig.TAG_WM;
     27 
     28 import android.os.Looper;
     29 import android.util.Slog;
     30 import android.view.InputChannel;
     31 import android.view.InputDevice;
     32 import android.view.InputEvent;
     33 import android.view.InputEventReceiver;
     34 import android.view.MotionEvent;
     35 
     36 /**
     37  * Input receiver for drag and drop
     38  */
     39 class DragInputEventReceiver extends InputEventReceiver {
     40     private final DragDropController mDragDropController;
     41 
     42     // Set, if stylus button was down at the start of the drag.
     43     private boolean mStylusButtonDownAtStart;
     44     // Indicates the first event to check for button state.
     45     private boolean mIsStartEvent = true;
     46     // Set to true to ignore input events after the drag gesture is complete but the drag events
     47     // are still being dispatched.
     48     private boolean mMuteInput = false;
     49 
     50     DragInputEventReceiver(InputChannel inputChannel, Looper looper,
     51             DragDropController controller) {
     52         super(inputChannel, looper);
     53         mDragDropController = controller;
     54     }
     55 
     56     @Override
     57     public void onInputEvent(InputEvent event, int displayId) {
     58         boolean handled = false;
     59         try {
     60             if (!(event instanceof MotionEvent)
     61                     || (event.getSource() & SOURCE_CLASS_POINTER) == 0
     62                     || mMuteInput) {
     63                 return;
     64             }
     65             final MotionEvent motionEvent = (MotionEvent) event;
     66             final float newX = motionEvent.getRawX();
     67             final float newY = motionEvent.getRawY();
     68             final boolean isStylusButtonDown =
     69                     (motionEvent.getButtonState() & BUTTON_STYLUS_PRIMARY) != 0;
     70 
     71             if (mIsStartEvent) {
     72                 // First event and the button was down, check for the button being
     73                 // lifted in the future, if that happens we'll drop the item.
     74                 mStylusButtonDownAtStart = isStylusButtonDown;
     75                 mIsStartEvent = false;
     76             }
     77 
     78             switch (motionEvent.getAction()) {
     79                 case ACTION_DOWN:
     80                     if (DEBUG_DRAG) Slog.w(TAG_WM, "Unexpected ACTION_DOWN in drag layer");
     81                     return;
     82                 case ACTION_MOVE:
     83                     if (mStylusButtonDownAtStart && !isStylusButtonDown) {
     84                         if (DEBUG_DRAG) {
     85                             Slog.d(TAG_WM, "Button no longer pressed; dropping at " + newX + ","
     86                                     + newY);
     87                         }
     88                         mMuteInput = true;
     89                     }
     90                     break;
     91                 case ACTION_UP:
     92                     if (DEBUG_DRAG) {
     93                         Slog.d(TAG_WM, "Got UP on move channel; dropping at " + newX + "," + newY);
     94                     }
     95                     mMuteInput = true;
     96                     break;
     97                 case ACTION_CANCEL:
     98                     if (DEBUG_DRAG) Slog.d(TAG_WM, "Drag cancelled!");
     99                     mMuteInput = true;
    100                     break;
    101                 default:
    102                     return;
    103             }
    104 
    105             mDragDropController.handleMotionEvent(!mMuteInput /* keepHandling */, newX, newY);
    106             handled = true;
    107         } catch (Exception e) {
    108             Slog.e(TAG_WM, "Exception caught by drag handleMotion", e);
    109         } finally {
    110             finishInputEvent(event, handled);
    111         }
    112     }
    113 }
    114