java - 处理3.0科泰相机。图片无法保存

Question

您好，我正在使用 processing 3.0 和 ketai library，我正在尝试保存图像，但由于某种原因它不起作用。每个按钮都有自己的监听器，以便识别它是否被按下。相机正常打开，但按下保存按钮时没有任何反应。处理控制台中显示一条错误消息。控制台中显示的消息是:

failed to create directory to save photo: /storage/emulated/0/Pictures/testing6

testing6 是我正在处理的 .pde 文件。此外，我正在 android 模拟器而不是 android 设备上测试应用程序。我希望能够保存图像并创建包含图像的文件夹。例如，一个文件夹将有动物照片，另一个文件夹将有风景等。创建任意数量的文件夹和照片。我在 Ketai 库和 GitHub 上看到了文档，但找不到解决方案。

import ketai.camera.*; 
import java.lang.String.*;  
KetaiCamera camera;



void setup()  
{
    camera = new KetaiCamera(this,width,height/2,15); 
    // 0: back camera; 1: front camera 
    camera.setCameraID(0); 
}  

void draw()  
{  
     image(camera, width/2, height/2, width, height);  
     drawUI();
}  

void drawUI()  
{  
     fill(255);
     stroke(0);
     orientation(LANDSCAPE);
     //here there is a for loop to create the buttons when the camera open
     //there are many buttons in other pages that is why we start from 28.
     for(int i = 28; i <= 31; i++)        
     {
         buttons[i].draw(color(0,128),textColor);
     }
} 

void onCameraPreviewEvent()  
{  
    camera.read(); 
} 

void onSavePhotoEvent(String filename)  
{  
    camera.addToMediaLibrary(filename);  
}  

//mousePressed is a build-in function and I check which button was pressed.
//each button has on click listener.
void mousePressed()  
{  
    if(buttons[28].isPressed())          //button Start, PAGE CAMERA 
    {
        if (camera.isStarted())
        {
            camera.stop();
        }
        else
        {
            if (!camera.start())
            {
                println("Failed to start camera.");
            }
        }
    }//end of if statement for the START button

    else if(buttons[29].isPressed())        //button Save, PAGE CAMERA
    {
        if(camera.isStarted())
        {
            camera.savePhoto("test.png");
        }
    }//end of else if for the SAVE button

    else if(buttons[30].isPressed())        //button Flash, PAGE CAMERA
    {
        if (camera.isFlashEnabled())
        {
            camera.disableFlash();
        }
        else
        {
            camera.enableFlash();
        }
    }//end of else if statement for the Flash button

    else if(buttons[31].isPressed())      //button Exit, PAGE CAMERA
    {
        camera.stop();
    }//end of else if statement for the Exit button

}//end of mousePressed function

Answer 1

较新版本的 Android 会在运行时而非安装期间要求用户授予访问敏感资源的权限。因此，在调用 KetaiCamera::savePhoto() 之前，您需要提示用户授予您的应用写入文件系统的权限。。

来自Processing for Android documentation :

void setup() {
  requestPermission("android.permission.WRITE_EXTERNAL_STORAGE", "checkPermission");
}

void checkPermission(boolean wasPermissionGranted){
    if (wasPermissionGranted)
        println("Hooray! I can now write to the local file system!");
    else 
        println("Oh no! I was not granted write permission =(");
}