qt android开发篇之如何实现在不同分辨率手机中自适应字体大小，或者像素什么的

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我们知道现在手机屏幕的分辨率跟电脑的分辨率不同，或许你直接在电脑中设置的字体像素大小为20，在电脑中运行的时候看起来很正常的字体，但是部署到手机后大家分先那些字看起来像蚂蚁一样小，这时候改怎么办呢？小编通过调用android api来解决这个问题，本来很高兴的说发现qt中的qpplicationwindows这个有一个devicePixelRatio属性，但是它的值我不知道怎么算到手机上，所以只能调用android API了！源码： Screen.java

package com.tommego.work;//tommegoimport java.util.List;import android.content.Context;//屏幕像素密度import android.util.DisplayMetrics;//蓝牙 开关import android.bluetooth.BluetoothAdapter;public class Screen extends org.qtproject.qt5.android.bindings.QtActivity{    private static Screen m_instance;//单例对象    private static BluetoothAdapter m_bluetoothAdapter;//蓝牙控制对象    public Screen(){        m_instance = this;//实例化单例对象        m_bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();        if (!m_bluetoothAdapter.isEnabled()){            //打开蓝牙            m_bluetoothAdapter.enable();        }    }    //获取屏幕像素密度    public static double getDentisy(){        DisplayMetrics metrics=new DisplayMetrics();        m_instance.getWindowManager().getDefaultDisplay().getMetrics(metrics);        return metrics.density;//        return 3;    }}

devicescreen.h

#ifndef DEVICESCREEN_H#define DEVICESCREEN_H#include <QObject>#include <QAndroidJniObject>#include <QList>#include <QString>class DeviceScreen : public QObject{    Q_OBJECTpublic:    explicit DeviceScreen();    ~DeviceScreen();    Q_PROPERTY(double dentisty READ dentisty WRITE setDentisty NOTIFY dentistyChanged)    //获取屏幕像素密度    Q_INVOKABLE double getDentisy();    double dentisty(){        return this->m_dentisty;    }    void setDentisty(double a){        this->m_dentisty=a;    }signals:    void dentistyChanged();public slots://    void onDentistyChangedprivate:    double m_dentisty;};#endif // DEVICESCREEN_H>##devicscreen.cpp#include"devicescreen.h"DeviceScreen::DeviceScreen(){    m_dentisty=getDentisy();    dentistyChanged();}DeviceScreen::~DeviceScreen(){}//获取屏幕像素密度double DeviceScreen::getDentisy(){    return QAndroidJniObject::callStaticMethod<double>("com/tommego/work/Screen",                                                    "getDentisy","()D");}

main.cpp

#include <QApplication>#include <QQmlApplicationEngine>#include <QtQml>#include <QQmlContext>#include "Device/devicescreen.h"int main(int argc, char *argv[]){    QApplication app(argc, argv);    QQmlApplicationEngine engine;    qmlRegisterType<DeviceScreen>("Device",1,0,"MyDevice");//    QQmlContext *context = new QQmlContext(engine.rootContext());    DeviceScreen device;//    context->setContextProperty("mydevice",&device);//    context->set    engine.rootContext()->setContextProperty("mydevice",&device);    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));    return app.exec();}

main.qml

import QtQuick 2.4import QtQuick.Controls 1.3import QtQuick.Window 2.2ApplicationWindow {    width: Screen.desktopAvailableWidth    height: Screen.desktopAvailableHeight    visible: true    Text{            text:"hello"            font.pixelSize:20*mydevice.dentisty//设置字体大小            anchors.centerIn:parent    }}

转载：http://ju.outofmemory.cn/entry/200667

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