手电筒（火炬）正在打开，但不打烊 [英] Flashlight (Torch) is opening but not closing

问题描述

以下是code这是我用于打开火炬和关闭它。但是，当我关闭它，它崩溃。 LogCat中说！运行时异常：无法连接到相机服务

+
hasFlash没有得到任何值，并抛出空指针异常。 （我用它来检查闪光灯present与否。）

什么我做错了？

 布尔hasFlash = this.getPackageManager（）hasSystemFeature（PackageManager.FEATURE_CAMERA_FLASH）。
如果（hasFlash ==真）{            如果（s.equalsIgnoreCase（手电筒）|| s.equalsIgnoreCase（闪光灯开））
            {
                相机凸轮= Camera.open（）;
                参数P = cam.getParameters（）;
                p.setFlashMode（Parameters.FLASH_MODE_TORCH）;
                cam.setParameters（P）;
                返回打开;            }
            如果（s.equalsIgnoreCase（手电筒关）|| s.equalsIgnoreCase（闪光灯关））
            {                相机凸轮= Camera.open（）;
                参数P = cam.getParameters（）;
                p.setFlashMode（Parameters.FLASH_MODE_OFF）;
                cam.setParameters（P）;
                cam.stop preVIEW（）;
                cam.release（）;                返回关闭;
            }
            }
            其他
            {
                回归不能使用闪光灯;
            }
 

解决方案

修改

 相机Cam = Camera.open（）;
参数P = cam.getParameters（）;
p.setFlashMode（Parameters.FLASH_MODE_OFF）;
cam.setParameters（P）;
cam.stop preVIEW（）;
cam.release（）;返回关闭;
 

到

  cam.stop preVIEW（）;
cam.release（）;返回关闭;
 

我遇到了很多这些问题建立一个开源的手电筒为Android可以帮助你进一步的问题。

乔手电筒github上

Following is the code which I used for opening Torch and closing it. But when I close it, it crashes. LogCat says " Runtime Exception : Fail to connect to camera service "!

+ hasFlash is not getting any value and is throwing Nullpointer exception. (I'm using it to check if the flash is present or not.)

What am I doing Wrong?

boolean hasFlash = this.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);
if(hasFlash==true)

{

            if(s.equalsIgnoreCase("FlashLight On") || s.equalsIgnoreCase("Flash Light On"))
            {
                Camera cam = Camera.open();     
                Parameters p = cam.getParameters();
                p.setFlashMode(Parameters.FLASH_MODE_TORCH);
                cam.setParameters(p);
                return "Turning on";

            }
            if(s.equalsIgnoreCase("FlashLight Off") || s.equalsIgnoreCase("Flash Light Off"))
            {

                Camera cam = Camera.open();
                Parameters p = cam.getParameters();
                p.setFlashMode(Parameters.FLASH_MODE_OFF);
                cam.setParameters(p);
                cam.stopPreview();
                cam.release();

                return "Turning off";
            }
            }
            else
            {
                return "Flash Not Available";
            }

解决方案

Change

Camera cam = Camera.open();
Parameters p = cam.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_OFF);
cam.setParameters(p);
cam.stopPreview();
cam.release();

return "Turning off";

to

cam.stopPreview();
cam.release();

return "Turning off";

I ran into a lot of these issues building an open source flashlight for Android which may help you with further questions.

Flashlight by Joe github

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