QtQuick获取屏幕信息

/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/ **
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of The Qt Company Ltd nor the names of its
**     contributors may be used to endorse or promote products derived
**     from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/

import QtQuick 2.3
import QtQuick.Window 2.1

Item {
id: root
width: 400
height: propertyGrid.implicitHeight + 16

function orientationToString(o) {
switch (o) {
case Qt.PrimaryOrientation:
return "primary";
case Qt.PortraitOrientation:
return "portrait";
case Qt.LandscapeOrientation:
return "landscape";
case Qt.InvertedPortraitOrientation:
return "inverted portrait";
case Qt.InvertedLandscapeOrientation:
return "inverted landscape";
}
return "unknown";
}

Grid {
id: propertyGrid
columns: 2
spacing: 8
x: spacing
y: spacing

Text {
text: "Screen \"" + Screen.name + "\":"
font.bold: true
}
Item { width: 1; height: 1 } // spacer

Text { text: "dimensions" }
Text { text: Screen.width + "x" + Screen.height }

Text { text: "pixel density" }
Text { text: Screen.pixelDensity.toFixed(2) + " dots/mm (" + (Screen.pixelDensity * 25.4).toFixed(2) + " dots/inch)" }

Text { text: "logical pixel density" }
Text { text: Screen.logicalPixelDensity.toFixed(2) + " dots/mm (" + (Screen.logicalPixelDensity * 25.4).toFixed(2) + " dots/inch)" }

Text { text: "device pixel ratio" }
Text { text: Screen.devicePixelRatio.toFixed(2) }

Text { text: "available virtual desktop" }
Text { text: Screen.desktopAvailableWidth + "x" + Screen.desktopAvailableHeight }

Text { text: "orientation" }
Text { text: orientationToString(Screen.orientation) + " (" + Screen.orientation + ")" }

Text { text: "primary orientation" }
Text { text: orientationToString(Screen.primaryOrientation) + " (" + Screen.primaryOrientation + ")" }
}
}

http://doc.qt.io/qt-5/qtquick-window-screeninfo-qml.html

设置屏幕方向为横向，在AndroidManifest.xml文件中:

<activity android:screenOrientation="portrait" ...

http://stackoverflow.com/questions/20774498/qml-screen-orientation-lock

https://forum.qt.io/topic/49120/how-to-lock-screen-orientation-qml-android-ios/3

屏幕方向选项值：

1.landscape：横屏(风景照)，显示时宽度大于高度；

2.portrait：竖屏(肖像照)， 显示时高度大于宽度；

3.user：用户当前的首选方向；

4.behind：继承Activity堆栈中当前Activity下面的那个Activity的方向；

5.sensor：由物理感应器决定显示方向，它取决于用户如何持有设备，当设备被旋转时方向会随之变化——在横屏与竖屏之间；

6.nosensor：忽略物理感应器——即显示方向与物理感应器无关，不管用户如何旋转设备显示方向都不会随着改变(“unspecified”设置除外)；

7.unspecified：未指定，此为默认值，由Android系统自己选择适当的方向，选择策略视具体设备的配置情况而定，因此不同的设备会有不同的方向选择；

其他信息：

为app添加收费功能:

http://blog.qt.io/blog/2013/12/12/implementing-in-app-purchase-on-android/