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[英]Trying to save imageView image to gallery, but cannot saved to gallery.(Android)
[英]Trying to save image to gallery
我是Android開發的新手,嘗試將圖像保存到圖庫時有些卡住。 我已經按照https://developer.android.com/training/camera/photobasics上的指南進行操作,並且在我嘗試使用getExternalStoragePublicDirectory將圖像保存到手機上的圖庫之前,它一直工作正常。
當我使用getExternalFilesDir()時,所有工作正常,但是當我嘗試使用getExternalStoragePublicDirectory將圖片獲取到畫廊時,我得到了NullPointerException。 我已經向清單添加了WRITE_EXTERNAL_STORAGE權限。
我曾嘗試閱讀有關此問題的其他文章,但還沒有發現對這個問題的任何啟示。
這是我的代碼。 如果annyone可以幫助我找出導致NullPointerException異常的原因,我將不勝感激。
private File createImageFile() throws IOException {
// Create an image file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
File image = File.createTempFile(
imageFileName, /* prefix */
".jpg", /* suffix */
storageDir /* directory */
);
// Save a file: path for use with ACTION_VIEW intents
mCurrentPhotoPath = image.getAbsolutePath();
return image;
}
private void dispatchTakePictureIntent() {
Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
// Ensure that there's a camera activity to handle the intent
if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
// Create the File where the photo should go
File photoFile = null;
try {
photoFile = createImageFile();
} catch (IOException ex) {
// Error occurred while creating the File
}
// Continue only if the File was successfully created
if (photoFile != null) {
Uri photoURI = FileProvider.getUriForFile(this,
"com.example.android.fileprovider",
photoFile);
takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);
startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);
}
}
}
private void galleryAddPic() {
Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
File f = new File(mCurrentPhotoPath);
Uri contentUri = Uri.fromFile(f);
mediaScanIntent.setData(contentUri);
this.sendBroadcast(mediaScanIntent);
}
這是我在Logcat中的錯誤:
08-02 20:04:12.920 17455-17455/com.example.android.fishlist E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.android.fishlist, PID: 17455
java.lang.NullPointerException
at java.io.File.<init>(File.java:282)
at com.example.android.fishlist.NewCatch.galleryAddPic(NewCatch.java:192)
at com.example.android.fishlist.NewCatch.access$200(NewCatch.java:45)
at com.example.android.fishlist.NewCatch$2.onClick(NewCatch.java:101)
at android.view.View.performClick(View.java:6891)
at android.widget.TextView.performClick(TextView.java:12651)
at android.view.View$PerformClick.run(View.java:26083)
at android.os.Handler.handleCallback(Handler.java:789)
at android.os.Handler.dispatchMessage(Handler.java:98)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6938)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374)
我認為這行代碼會使您的應用崩潰
File f = new File(mCurrentPhotoPath); // mCurrentPhotoPath is null
從更改代碼
// Create an image file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
File image = File.createTempFile(
imageFileName, /* prefix */
".jpg", /* suffix */
storageDir /* directory */
);
至
// Create an image file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
File file = new File(storageDir.getPath() + File.separator + imageFileName + ".jpg");
注意:如果您的應用程序在Android 6或更高版本上運行,請確保處理運行時權限。
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