QGIS二次开发第二讲

第一步：新建Qt Application 项目，名称为：qgis2，完成后，其解决方案的文件如下所示

第二步，设计UI

（1）双击，qgis2.ui文件，弹出qtDesigner设计器，添加相应菜单（对应的Action命名）如下图所示





（2）在面板中央的centralWidget中拖入一个QFrame容器（用来包含qgsmapcanvas），命名为frameMap；

（3）在qtDesigner中，点击保存，退出。

（4）在项目解决方案中，有点点击qgis2.ui，点击编译，使其重新生成ui_qgis2.h这个文件

第三步：修改qgis2.h文件

（PS:在Generated Files中有个ui_qgis2.h文件，此文件是有qgis2.ui文件自动生成的，无需修改，如需用到此类，用法当如：Ui::qgis2Class，如下代码所示）

修改的qigs2.h文件如下：

[cpp] view
plaincopy

#ifndef QGIS2_H

#define QGIS2_H

#include <QtGui/QMainWindow>

#include "ui_qgis2.h"

#include <qgsapplication.h>

#include <qgsproviderregistry.h>

#include <qgssinglesymbolrenderer.h>

#include <qgsmapcanvas.h>

#include <qgsvectorlayer.h>

#include <qgsmaptool.h>

#include <QtGui/QVBoxLayout>

#include <qgsmaplayerregistry.h>

#include <QtGui/QToolBar>

#include<qgsmaptoolpan.h>

#include <qgsmaptoolzoom.h>

class qgis2 : public QMainWindow,private Ui::qgis2Class

{

Q_OBJECT

public:

qgis2(QWidget *parent = 0, Qt::WFlags flags = 0);

~qgis2();

public slots:

void zoomInMode();

void zoomOutMode();

void panMode();

void addLayer();

private:

Ui::qgis2Class ui;

QgsMapCanvas *mpMapCanvas;

QVBoxLayout *mpMapLayout;

QToolBar * mpMapToolBar;

QgsMapTool *mpPanTool;

QgsMapTool *mpZoomInTool;

QgsMapTool *mpZoomOutTool;

};

#endif // QGIS2_H

第四步：修改qgis2.cpp文件

[cpp] view
plaincopy

#include "qgis2.h"

qgis2::qgis2(QWidget *parent, Qt::WFlags flags)

: QMainWindow(parent, flags)

{

ui.setupUi(this);

QString myPluginsDir = "c:/Program Files/qgis1.7.0/plugins";

QgsProviderRegistry::instance(myPluginsDir);

//创建地图画布

mpMapCanvas= new QgsMapCanvas(0,0);

mpMapCanvas->freeze(false);

mpMapCanvas->enableAntiAliasing(true);

mpMapCanvas->setCanvasColor(QColor(255,255,255));

mpMapCanvas->useImageToRender(false);

mpMapCanvas->setVisible(true);

mpMapCanvas->refresh();

mpMapCanvas->show();

mpMapCanvas->setFocus();

//将窗口部件布局

mpMapLayout = new QVBoxLayout();

mpMapLayout->addWidget(mpMapCanvas);

ui.frameMap->setLayout(mpMapLayout);

setCentralWidget(ui.frameMap);

//创建Action行为

connect(ui.mpActionPan,SIGNAL(triggered()),this,SLOT(panMode()));

connect(ui.mpActionZoomIn,SIGNAL(triggered()),this,SLOT(zoomInMode()));

connect(ui.mpActionZoomOut,SIGNAL(triggered()),this,SLOT(zoomOutMode()));

connect(ui.mpActionAddLayer,SIGNAL(triggered()),this,SLOT(addLayer()));

//创建工具条功能

mpMapToolBar=addToolBar(tr("File"));

mpMapToolBar->addAction(ui.mpActionAddLayer);

mpMapToolBar->addAction(ui.mpActionPan);

mpMapToolBar->addAction(ui.mpActionZoomIn);

mpMapToolBar->addAction(ui.mpActionZoomOut);

//创建maptool功能

mpPanTool= new QgsMapToolPan(mpMapCanvas);

mpPanTool->setAction(ui.mpActionPan);

mpZoomInTool = new QgsMapToolZoom(mpMapCanvas,FALSE);

mpZoomInTool->setAction(ui.mpActionZoomIn);

mpZoomOutTool = new QgsMapToolZoom(mpMapCanvas,TRUE);

mpZoomOutTool->setAction(ui.mpActionZoomOut);

}

qgis2::~qgis2()

{

delete mpZoomOutTool;

delete mpZoomInTool;

delete mpPanTool;

delete mpMapToolBar;

delete mpMapCanvas;

delete mpMapLayout;

}

void qgis2::panMode()

{

mpMapCanvas->setMapTool(mpPanTool);

}

void qgis2::zoomInMode()

{

mpMapCanvas->setMapTool(mpZoomInTool);

}

void qgis2::zoomOutMode()

{

mpMapCanvas->setMapTool(mpZoomOutTool);

}

void qgis2::addLayer()

{

//读取矢量数据

QString myLayerPath ="E:\\Qgis\\project\\qgis2\\data";// 此处换成自己的矢量文件

QString myLayerBaseName = "test";

QString myPoviderName="ogr";

QList<QgsMapCanvasLayer> myLayerSet;

QgsVectorLayer* myLayer = new QgsVectorLayer(myLayerPath,myLayerBaseName,myPoviderName);

if (myLayer->isValid())

{

QgsSingleSymbolRenderer *myRenderer = new QgsSingleSymbolRenderer(myLayer->geometryType());

myLayer->setRenderer(myRenderer);

//增加矢量数据到图层注册

QgsMapLayerRegistry::instance()->addMapLayer(myLayer,true);

//设置画布的extent

mpMapCanvas->setExtent(myLayer->extent());

//设置画布的图层数据集

myLayerSet.append(QgsMapCanvasLayer(myLayer));

mpMapCanvas->setLayerSet(myLayerSet);

}

else

{

return;

}

}

第五步：修改main.cpp文件

[cpp] view
plaincopy

#include "qgis2.h"

#include <QtGui/QApplication>

int main(int argc, char *argv[])

{

QgsApplication a(argc, argv,TRUE);

qgis2 w;

w.show();

return a.exec();

}

第六步：运行结果如下：