1 2Android DragAndDropAcrossApps-new Sample 3=================================== 4 5This sample contains two separate Android applications: DragSource and 6DropTarget. DragSource contains images and text that can be dropped into the DropTarget 7app. Images are shared between the two apps through a URI for which the receiving app 8must request permission first, before it can be used. 9 10It also demonstrates the use of the DragStartHelper from the v13 support library to easily 11handle drag and drop events. 12 13Introduction 14------------ 15 16Android N introduces support for drag and drop between applications, 17augmenting the existing APIs that have enabled this within a single 18window before. 19 20To start a drag operation you need to call `View.startDragAndDrop`. 21Which gesture or action triggers this is up to you as an app developer. 22The API guide recommends doing this from 23`View.OnLongClickListener.onLongClick` and this seems to be the de-facto 24standard, but you are free to use other gestures (single tap, tap and drag 25etc). 26However, if you go for a unconventional drag start gesture, note that 27the framework implementation assumes that the pointer (touch or mouse) 28is down while the drag is starting, and the most recent touch/click 29position is used as the original position of the drag shadow. 30 31See also `android.support.v13.view.DragStartHelper` which uses different 32gestures for touch and mouse (click and drag works better for mouse 33than a long click). 34 35By default a drag and drop operation is constrained by the window 36containing the view that started the drag. 37To enable cross-window and cross-app drag and drop add 38`View.DRAG_FLAG_GLOBAL` to the flags passed to the `View.startDragAndDrop` 39call. 40 41If a Uri requiring permission grants is being sent, then the 42`android.view.View.DRAG_FLAG_GLOBAL_URI_READ` and/or the 43`android.view.View.DRAG_FLAG_GLOBAL_URI_WRITE` flags must be used also. 44To access content URIs requiring permissions on the receiving side, the target 45app needs to request the `android.view.DropPermissions` from the activity via 46`android.app.Activity.requestDropPermissions`. This permission will stay either 47until the activity is alive, or until the `release()` method is called on the 48`android.view.DropPermissions` object. 49 50Pre-requisites 51-------------- 52 53- Android SDK 28 54- Android Build Tools v28.0.3 55- Android Support Repository 56 57Screenshots 58------------- 59 60<img src="screenshots/phone.png" height="400" alt="Screenshot"/> <img src="screenshots/tablet.png" height="400" alt="Screenshot"/> 61 62Getting Started 63--------------- 64 65This sample uses the Gradle build system. To build this project, use the 66"gradlew build" command or use "Import Project" in Android Studio. 67 68Support 69------- 70 71- Google+ Community: https://plus.google.com/communities/105153134372062985968 72- Stack Overflow: http://stackoverflow.com/questions/tagged/android 73 74If you've found an error in this sample, please file an issue: 75https://github.com/googlesamples/android-DragAndDropAcrossApps-new 76 77Patches are encouraged, and may be submitted by forking this project and 78submitting a pull request through GitHub. Please see CONTRIBUTING.md for more details. 79 80License 81------- 82 83Copyright 2019 The Android Open Source Project, Inc. 84 85Licensed to the Apache Software Foundation (ASF) under one or more contributor 86license agreements. See the NOTICE file distributed with this work for 87additional information regarding copyright ownership. The ASF licenses this 88file to you under the Apache License, Version 2.0 (the "License"); you may not 89use this file except in compliance with the License. You may obtain a copy of 90the License at 91 92http://www.apache.org/licenses/LICENSE-2.0 93 94Unless required by applicable law or agreed to in writing, software 95distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 96WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 97License for the specific language governing permissions and limitations under 98the License. 99
