Android - 通过 Intent 拍摄照片并使用自定义名称将它们保存到自定义目的地 [英] Android - Taking photos and saving them with a custom name to a custom destination via Intent

问题描述

我有一个程序可以通过 Intent 打开相机拍照.大部分工作已经很好了.但是，我希望它以某个文件名保存到某个文件夹(文件名是可选的，但它真的很有帮助).

I have a program that opens the camera via Intent to take a photo. That much part works fine already. However, I want it to save to a certain folder with a certain file name (the file name is optional but it would really really help).

这就是我目前所拥有的.

So here's what I have so far.

这是打开相机的代码行:

Here's the line of code that opens the camera:

//TODO camera stuff.
Intent openCam = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

//The two lines of code below were commented out at first.
//They were eventually added when I tried to save it with a custom name and destination
fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE); // create a file to save the image
openCam.putExtra(MediaStore.EXTRA_OUTPUT, fileUri); // set the image file name

startActivityForResult(openCam, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);

结果处理程序在这里:

//TODO handle result
if (requestCode == CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE) {
   if (resultCode == RESULT_OK) {
         // Image captured and saved to fileUri specified in the Intent
         Toast.makeText(this, "Image saved to:
" +
                     data.getData(), Toast.LENGTH_LONG).show();
            System.out.println("I am here");

   } 
   else if (resultCode == RESULT_CANCELED) {
            // User cancelled the image capture
   } 
   else {
            // Image capture failed, advise user
   }
}

在我实现以下两种方法之前，代码运行良好.但是，它以默认文件名(时间戳版本)保存到默认文件夹中.Toast 显示Imaged saved to: null"，因为我还没有设置那部分.

Before I implemented the two methods below, the code was working fine. However it was saved to the default folder with the default file name (the time stamp version). The toast displayed "Imaged saved to: null" since I haven't set that part yet.

这里是应该处理自定义文件名和目的地的方法

So here are the methods that were supposed to handle the custom filename and destination

/** Create a file Uri for saving an image or video */
private static Uri getOutputMediaFileUri(int type){
      return Uri.fromFile(getOutputMediaFile(type));
}

/** Create a File for saving an image or video */
private static File getOutputMediaFile(int type){
    // To be safe, you should check that the SDCard is mounted
    // using Environment.getExternalStorageState() before doing this.

    Environment.getExternalStorageState();

    File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
              Environment.DIRECTORY_PICTURES), "MyCameraApp");
    // This location works best if you want the created images to be shared
    // between applications and persist after your app has been uninstalled.

    // Create the storage directory if it does not exist
    if (! mediaStorageDir.exists()){
        if (! mediaStorageDir.mkdirs()){
            Log.d("MyCameraApp", "failed to create directory");
            return null;
        }
    }

    // Create a media file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    File mediaFile;
    if (type == MEDIA_TYPE_IMAGE){
        mediaFile = new File(mediaStorageDir.getPath() + File.separator +
        "IMG_"+ timeStamp + ".jpg");
    } else {
        return null;
    }

    return mediaFile;
}

*这些代码摘自 developer.android.com 的相机指南.

*These code were lifted from the Camera Guide from developer.android.com.

上面的代码设法打开相机并拍照并保存它们.但是，当用户决定停止拍照并按返回键时，就会出现问题.发生的情况是应用程序强制关闭并出现此错误:

The code above manages to open the Camera and take photos and save them. However, the problem occurs when the user decides to stop taking photos and press the back key. What happens is that the app force closes giving this error:

10-21 12:44:33.699: E/AndroidRuntime(13016): FATAL EXCEPTION: main
10-21 12:44:33.699: E/AndroidRuntime(13016): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=100, result=-1, data=null} to activity {com.AIC.QRCodeScanner/com.AIC.QRCodeScanner.QRCodeScanner}: java.lang.NullPointerException
10-21 12:44:33.699: E/AndroidRuntime(13016): at android.app.ActivityThread.deliverResults(ActivityThread.java:2536)
10-21 12:44:33.699: E/AndroidRuntime(13016): at android.app.ActivityThread.handleSendResult(ActivityThread.java:2578)
10-21 12:44:33.699: E/AndroidRuntime(13016): at android.app.ActivityThread.access$2000(ActivityThread.java:117)
10-21 12:44:33.699: E/AndroidRuntime(13016): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:965)
10-21 12:44:33.699: E/AndroidRuntime(13016): at android.os.Handler.dispatchMessage(Handler.java:99)
10-21 12:44:33.699: E/AndroidRuntime(13016): at android.os.Looper.loop(Looper.java:123)
10-21 12:44:33.699: E/AndroidRuntime(13016): at android.app.ActivityThread.main(ActivityThread.java:3691)
10-21 12:44:33.699: E/AndroidRuntime(13016): at java.lang.reflect.Method.invokeNative(Native Method)
10-21 12:44:33.699: E/AndroidRuntime(13016): at java.lang.reflect.Method.invoke(Method.java:507)
10-21 12:44:33.699: E/AndroidRuntime(13016): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:847)
10-21 12:44:33.699: E/AndroidRuntime(13016): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605)
10-21 12:44:33.699: E/AndroidRuntime(13016): at dalvik.system.NativeStart.main(Native Method)
10-21 12:44:33.699: E/AndroidRuntime(13016): Caused by: java.lang.NullPointerException
10-21 12:44:33.699: E/AndroidRuntime(13016): at com.AIC.QRCodeScanner.QRCodeScanner.onActivityResult(QRCodeScanner.java:379)
10-21 12:44:33.699: E/AndroidRuntime(13016): at android.app.Activity.dispatchActivityResult(Activity.java:3934)
10-21 12:44:33.699: E/AndroidRuntime(13016): at android.app.ActivityThread.deliverResults(ActivityThread.java:2532)
10-21 12:44:33.699: E/AndroidRuntime(13016):    
... 11 more

它指向的行将是这一行(第 379 行):data.getData(), Toast.LENGTH_LONG

The line it points to would be this line (line 379): data.getData(), Toast.LENGTH_LONG

但是，这些文件与拍摄的 Instagram 照片一起保存在文件夹 /Pictures/MyCameraApp 中.

However, the files are saved at the folder /Pictures/MyCameraApp together with the Instagram photos that were taken.

所以问题是:1. 有没有办法让 onActivityResult 正常工作?我知道我只能求助于使用 startActivity 以免杀死应用程序.2. 有没有办法只用相机拍一张?因此，在用户保存照片后，应用程序将返回主活动.3. 另外，我可以将它保存到我自己的文件夹中吗?我不确定为什么它会将照片保存在 /Pictures/MyCameraApp 中，我希望它只保存到 /MyCameraApp.

So the questions are: 1. Is there a way to make onActivityResult work properly? I know I can just resort to using startActivity in order not to kill the app. 2. Is there a way to only take one shot with the camera? So after the user saves the photo, the app goes back to the main activity. 3. Also, can I save it to a folder of my own? I'm not sure why it saves the photos in /Pictures/MyCameraApp, I want it to save only to /MyCameraApp.

我想我在这里错过了一些简单的东西.

I think I'm missing out on something simple here.

推荐答案

这是使其工作的代码:

//camera stuff
Intent imageIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());

//folder stuff
File imagesFolder = new File(Environment.getExternalStorageDirectory(), "MyImages");
imagesFolder.mkdirs();

File image = new File(imagesFolder, "QR_" + timeStamp + ".png");
Uri uriSavedImage = Uri.fromFile(image);

imageIntent.putExtra(MediaStore.EXTRA_OUTPUT, uriSavedImage);
startActivityForResult(imageIntent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);

它打开相机并拍摄一张照片(在用户保存拍摄的图像后返回主活动.它将图像保存到指定的文件夹.

It opens the camera and takes exactly one shot (it goes back to the main activity after the user saves the image that was taken. It saves the image to the specified folder.

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