qt android/ios 通用截屏示例代码

Qt跨平台框架允许开发者轻松地在Android和iOS上实现屏幕截图功能。这里是一个简单的示例代码片段，它展示了如何在Qt的Android和iOS应用中捕获屏幕并保存到文件：

**对于Qt Android:**

// 引入所需的库
#include <QGuiApplication>
#include <QQmlEngine>
#include <QQuickImage>

// ... (其他Qt初始化代码)

QQuickImage screenShot;
if (screenShot.loadFromSource(QStringLiteral("qrc:/main.qml"))) { // 假设你有一个主窗口
    QImage qi = screenShot.toImage();
    QByteArray bytes;
    if (!qi.save(&bytes, "PNG")) {
        qCritical() << "Failed to save screenshot";
    } else {
        QFile file(QStringLiteral("screenshot.png")); // 创建截图文件
        if (file.open(QIODevice::WriteOnly | QIODevice::Truncate)) {
            file.write(bytes);
            file.close();
            qDebug() << "Screenshot saved successfully.";
        }
    }
}

**对于Qt iOS:**

在iOS上，你需要利用`UIWindow`和`UIGraphicsContext`来获取屏幕快照。由于Qt for iOS使用Objective-C，以下是Objective-C版本的代码：

#import <UIKit/UIKit.h>
#import <QtWidgets/QImageIO>

@interface MyClass : NSObject <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@end

@implementation MyClass

- (UIImage *)captureScreen {
    UIGraphicsBeginImageContextWithOptions(self.window.bounds.size, NO, 0.0);
    [self.window.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return image;
}

- (void)applicationDidFinishLaunching:(UIApplication *)application {
    // ... (其他启动逻辑)
    
    UIImage *screenshot = [self captureScreen];
    NSData *data = UIImagePNGRepresentation(screenshot);
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = paths[0];
    NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"screenshot.png"];
    [data writeToFile:filePath atomically:YES];

    NSLog(@"Screenshot saved at: %@", filePath);
}

@end

请注意，这只是一个基础示例，实际项目中可能需要处理更多细节，例如错误处理、资源路径管理等。