好吧所以我在模拟器上测试我的应用程序时遇到此问题（android 6.0）（因为我没有安装android 6.0设备），我首先要求用户在执行任务之前授予必要的权限，并在获得权限之后执行我的任务，但它给了我这个错误：
Unable to decode stream: java.io.FileNotFoundException: /storage/19FA-1F0B/DCIM/Image1464800718267.jpg: open failed: EACCES (Permission denied)
06-02 12:04:11.906 21595-21595/pb.myPackage D/AndroidRuntime: Shutting down VM
----------beginning of crash
06-02 12:04:11.907 21595-21595/pb.myPackage E/AndroidRuntime: FATAL EXCEPTION: main
Process: pb.myPackage, PID: 21595
java.lang.RuntimeException: Unable to start activity ComponentInfo{pb.myPackage/pb.myPackage.CropActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.graphics.Bitmap$Config android.graphics.Bitmap.getConfig()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.graphics.Bitmap$Config android.graphics.Bitmap.getConfig()' on a null object reference
我的整个代码在哪里询问然后执行我的任务：
if (Build.VERSION.SDK_INT >= 23){
if (ContextCompat.checkSelfPermission(context,
Manifest.permission.READ_EXTERNAL_STORAGE)
!= PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[] {Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE},
REQUEST_CODE_ASK_PERMISSIONS);
}else {
//Start Activity To Select Image From Gallery
Intent gallery_Intent = new Intent(getContext(), GalleryUtil.class);
gallery_Intent.putExtra("Switch", 0);
startActivityForResult(gallery_Intent, GALLERY_ACTIVITY_CODE);
}
}else {
//Start Activity To Select Image From Gallery
Intent gallery_Intent = new Intent(getContext(), GalleryUtil.class);
gallery_Intent.putExtra("Switch", 0);
startActivityForResult(gallery_Intent, GALLERY_ACTIVITY_CODE);
}
你可以看到我正在检查是否授予了必要的权限，但仍然得到了这个例外，最重要的一点是，这只发生在我第一次执行上述所有任务时，首先是用户授予我获得此错误的权限，但当我再次运行应用程序时，我没有得到任何例外，一切正常，
似乎当用户授予权限时，此新更改尚未在系统上更新，并且在重新启动后更改更新完成并且一切正常
onActivityResult:
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == GALLERY_ACTIVITY_CODE) {
if(resultCode == Activity.RESULT_OK) {
String picturePath = data.getStringExtra("picturePath");
//perform Crop on the Image Selected from Gallery
performCrop(picturePath);}}
if (requestCode == RESULT_CROP ) {
if(resultCode == Activity.RESULT_OK){
Bundle extras = data.getExtras();
Bitmap selectedBitmap = extras.getParcelable("data");
// Set The Bitmap Data To ImageView
imageView.setImageBitmap(selectedBitmap);
imageView.setScaleType(ImageView.ScaleType.FIT_XY);}}
}
private void performCrop(String imageUri) {
Intent cropIntent = new Intent(getActivity(), CropActivity.class );
cropIntent.putExtra("imageUri", imageUri);
startActivity(cropIntent);
getActivity().finish();
}
在获取图像后发送它进行裁剪，然后从那里得到图像，错误发生在CropActivity.class
galleryClass：
public class GalleryUtil extends Activity{
private final static int RESULT_SELECT_IMAGE = 100;
final private int REQUEST_CODE_ASK_PERMISSIONS = 123;
public static final int MEDIA_TYPE_IMAGE = 1;
private static final String TAG = "GalleryUtil";
String mCurrentPhotoPath;
File photoFile = null;
Intent selectedImageIntent;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try{
//Pick Image From Gallery
Intent i = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(i, RESULT_SELECT_IMAGE);
}catch(Exception e){
e.printStackTrace();
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch(requestCode){
case RESULT_SELECT_IMAGE:
if (resultCode == Activity.RESULT_OK && data != null && data.getData() != null) {
try{
Uri selectedImage = data.getData();
String[] filePathColumn = {MediaStore.Images.Media.DATA };
Cursor cursor = getContentResolver().query(selectedImage,
filePathColumn, null, null, null);
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
String picturePath = cursor.getString(columnIndex);
cursor.close();
//return Image Path to the Main Activity
Intent returnFromGalleryIntent = new Intent();
returnFromGalleryIntent.putExtra("Switch", false);
returnFromGalleryIntent.putExtra("picturePath",picturePath);
setResult(RESULT_OK,returnFromGalleryIntent);
finish();
}catch(Exception e){
e.printStackTrace();
Intent returnFromGalleryIntent = new Intent();
setResult(RESULT_CANCELED, returnFromGalleryIntent);
finish();
}
}else{
Log.i(TAG, "RESULT_CANCELED");
Intent returnFromGalleryIntent = new Intent();
setResult(RESULT_CANCELED, returnFromGalleryIntent);
finish();
}
break;
}
}
cropActivity：
public class CropActivity extends Activity {
File savedFile;
Button btnCancel;
Context context;
PhotoViewAttacher mAttacher;
Bitmap mImage;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.new_crop_actvity);
final CropImageView cropImageView = (CropImageView)findViewById(R.id.cropImageView);
final ImageView croppedImageView = (ImageView)findViewById(R.id.croppedImageView);
final ImageView bgImgView = (ImageView) findViewById(R.id.blurBGImgView);
btnCancel = (Button)findViewById(R.id.btnCancel);
context = this.getBaseContext();
mAttacher = new PhotoViewAttacher(croppedImageView);
Uri imgUri1 = Uri.parse(getIntent().getExtras().getString("imageUri"));
String UriStr = imgUri1.toString();
File f = new File(UriStr);
final String filePath = f.getPath();
Bitmap bitmap = BitmapFactory.decodeFile(filePath);
cropImageView.setImageBitmap(bitmap);
Bitmap blurredBitmap = Blur.fastblur(this, bitmap, 20);
bgImgView.setImageBitmap(blurredBitmap);
cropImageView.setCropMode(CropImageView.CropMode.CIRCLE);
//customising crop activity
cropImageView.setBackgroundColor(getResources().getColor(R.color.transparent));
cropImageView.setOverlayColor(0xAA1C1C1C);
cropImageView.setFrameColor(getResources().getColor(R.color.transparent));
cropImageView.setHandleColor(getResources().getColor(R.color.transparent));
cropImageView.setGuideColor(getResources().getColor(R.color.transparent));
// Set image for cropping
//cropImageView.setImageBitmap(BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher));
//cropImageView.setImageBitmap(mImage);
Button cropButton = (Button)findViewById(R.id.crop_button);
cropButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// Bitmap CroppedIamge = cropImageView.getCroppedBitmap();
// Get cropped image, and show result.
croppedImageView.setImageBitmap(cropImageView.getCroppedBitmap());
View content = croppedImageView;
content.setDrawingCacheEnabled(true);
Bitmap bitmap = content.getDrawingCache();
//
// File root = Environment.getExternalStorageDirectory();
// File file = new File(root.getAbsolutePath() + "/Download/img.jpg");
// File root = Environment.getExternalStorageDirectory();
File file = new File(context.getApplicationContext().getFilesDir() + "/img.gpj");
String path = file.getPath();
// File file = new File("/DCIM/Camera/image.jpg");
try {
file.createNewFile();
FileOutputStream ostream = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.JPEG, 60, ostream);
savedFile = new File(path);
ostream.close();
}
catch (Exception e)
{
e.printStackTrace();
}
croppedImageView.buildDrawingCache();
Bitmap CroppedIamge = croppedImageView.getDrawingCache();
Intent sendCroppedImgIntent = new Intent(CropActivity.this, MainActivity.class);
Bundle extras = new Bundle();
//extras.putParcelable("imagebitmap", CroppedIamge);
extras.putString("croppedImgUri", savedFile.toString() );
extras.putInt("Switch",1);
sendCroppedImgIntent.putExtras(extras);
startActivity(sendCroppedImgIntent);
}
});
}
public void cancel(View view) {
Intent cancelIntent = new Intent(CropActivity.this, MainActivity.class);
startActivity(cancelIntent);
}
}
答案 0 :(得分：0)
if (Build.VERSION.SDK_INT >= 23) {
if (ContextCompat.checkSelfPermission(ActivityName.this,
Manifest.permission.READ_EXTERNAL_STORAGE)
!= PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE},
REQUEST_CODE_ASK_PERMISSIONS);
} else {
Intent gallery_Intent = new Intent(getContext(), GalleryUtil.class);
gallery_Intent.putExtra("Switch", 0);
startActivityForResult(gallery_Intent, GALLERY_ACTIVITY_CODE);
}
} else {
//Start Activity To Select Image From Gallery
Intent gallery_Intent = new Intent(getContext(), GalleryUtil.class);
gallery_Intent.putExtra("Switch", 0);
startActivityForResult(gallery_Intent, GALLERY_ACTIVITY_CODE);
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
switch (requestCode) {
case REQUEST_CODE_ASK_PERMISSIONS:
final int numOfRequest = grantResults.length;
final boolean isGranted = numOfRequest == 1
&& PackageManager.PERMISSION_GRANTED == grantResults[numOfRequest - 1];
if (isGranted) {
Intent gallery_Intent = new Intent(getContext(), GalleryUtil.class);
gallery_Intent.putExtra("Switch", 0);
startActivityForResult(gallery_Intent, GALLERY_ACTIVITY_CODE);
}
break;
default:
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
}
}