我有一个程序可以通过 Intent 打开相机拍照。这么多部分已经很好了。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)。
这就是我到目前为止所拥有的。
这是打开相机的代码行:
//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:\n" +
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。吐司显示“图像已保存到:null”,因为我还没有设置那部分。
所以这里是应该处理自定义文件名和目标的方法
/** 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;
}
*这些代码来自 developer.android.com 的相机指南。
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给出此错误:
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
它指向的线将是这条线(第 379 行):data.getData(), Toast.LENGTH_LONG
/Pictures/MyCameraApp
但是,这些文件与拍摄的 Instagram 照片一起保存在该文件夹中。
所以问题是: 1.有没有办法让 onActivityResult 正常工作?我知道我可以诉诸使用 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,应用程序会返回到主要活动。3. 另外,我可以将它保存到我自己的文件夹中吗?我不确定它为什么将照片保存在 中/Pictures/MyCameraApp
,我希望它只保存到/MyCameraApp
.
我想我在这里错过了一些简单的东西。