Exception de pointeur nul lors d'une tentative de compression de bitmap
Je reçois une exception de pointeur null lorsque j'essaie de compresser une image bitmap afin de l'envoyer à un ByteArrayOutputStream afin d'obtenir un tableau d'octets. J'ai besoin de ce tableau d'octets pour pouvoir télécharger l'image dans ma base de données Parse en tant que fichier Parse. L'erreur de journal est indiquée ci-dessous.
01-11 23:29:41.522 32015-32015/com.example.whhsfbla.fashionnow E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.whhsfbla.fashionnow, PID: 32015
Java.lang.NullPointerException: Attempt to invoke virtual method 'boolean Android.graphics.Bitmap.compress(Android.graphics.Bitmap$CompressFormat, int, Java.io.OutputStream)' on a null object reference
at com.example.whhsfbla.fashionnow.PostActivity.uploadPost(PostActivity.Java:140)
at com.example.whhsfbla.fashionnow.PostActivity.access$100(PostActivity.Java:34)
at com.example.whhsfbla.fashionnow.PostActivity$2.onClick(PostActivity.Java:92)
at Android.view.View.performClick(View.Java:5254)
at Android.view.View$PerformClick.run(View.Java:21179)
at Android.os.Handler.handleCallback(Handler.Java:739)
at Android.os.Handler.dispatchMessage(Handler.Java:95)
at Android.os.Looper.loop(Looper.Java:145)
at Android.app.ActivityThread.main(ActivityThread.Java:6837)
at Java.lang.reflect.Method.invoke(Native Method)
at Java.lang.reflect.Method.invoke(Method.Java:372)
at com.Android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.Java:1404)
at com.Android.internal.os.ZygoteInit.main(ZygoteInit.Java:1199)
La ligne qui cause l'erreur est bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
public class PostActivity extends Activity {
private final int SELECT_PHOTO = 1;
private InputStream imageStream;
private Uri uploadFileUri;
private Bitmap bitmap;
private TextView txtPostTitle;
private EditText editText;
private Button btnChoosePic, btnUploadPost;
private ImageView imgPreview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_post);
txtPostTitle = (TextView) findViewById(R.id.txtPostTitle);
editText = (EditText) findViewById(R.id.editText);
btnChoosePic = (Button) findViewById(R.id.btnChoosePic);
btnUploadPost = (Button) findViewById(R.id.btnMakePost);
imgPreview = (ImageView) findViewById(R.id.imgPreview);
txtPostTitle.setText("Title:");
btnChoosePic.setText("Choose Picture");
btnUploadPost.setText("Create Post");
btnUploadPost.setEnabled(false);
/*btnChoosePic.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
openImageIntent();
} catch (IOException e) {
e.printStackTrace();
}
}
}); */
btnChoosePic.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
openImageIntent();
} catch (IOException e) {
e.printStackTrace();
}
}
});
btnUploadPost.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
uploadPost();
finish();
}
});
}
private void openImageIntent() throws IOException {
final File root = new File(Environment.getExternalStorageDirectory() +
File.separator + "MyDir" + File.separator);
root.mkdirs();
final String fileName = File.createTempFile("tmp", ".txt").getPath();
final File sdImageMainDirectory = new File(root, fileName);
uploadFileUri = Uri.fromFile(sdImageMainDirectory);
//Camera
final List<Intent> cameraIntents = new ArrayList<Intent>();
final Intent captureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
final PackageManager packageManager = getPackageManager();
final List<ResolveInfo> resolveInfoList = packageManager.queryIntentActivities(captureIntent, 0);
for (ResolveInfo res : resolveInfoList) {
final String packageName = res.activityInfo.packageName;
final Intent intent = new Intent(captureIntent);
intent.setComponent(new ComponentName(res.activityInfo.packageName, res.activityInfo.name));
intent.setPackage(packageName);
intent.putExtra(MediaStore.EXTRA_OUTPUT, uploadFileUri);
cameraIntents.add(intent);
}
//Filesystem
final Intent galleryIntent = new Intent();
galleryIntent.setType("image/*");
galleryIntent.setAction(Intent.ACTION_GET_CONTENT);
final Intent chooserIntent = Intent.createChooser(galleryIntent, "Select Source");
chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, cameraIntents.toArray(new Parcelable[cameraIntents.size()]));
startActivityForResult(chooserIntent, SELECT_PHOTO);
}
private void uploadPost() {
// Locate the image in res > drawable-hdpi
bitmap = BitmapFactory.decodeResource(getResources(), R.id.imgPreview);
// Convert it to byte
ByteArrayOutputStream stream = new ByteArrayOutputStream();
// Compress image to lower quality scale 1 - 100
bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
byte[] image = stream.toByteArray();
// Create the ParseFile
ParseFile file = new ParseFile("image.png",image);
// Upload the image into ParseCloud
file.saveInBackground();
// Create a New Class called "ImageUpload" in Parse
ParseObject post = new ParseObject("Post");
// Create a column named "ImageName" and set the string
post.put("title", editText.getText().toString());
// Create a column named "ImageFile" and insert the image
post.put("ImageFile", file);
post.put("user", User.username);
// Create the class and the columns
post.saveInBackground();
// Show a simple toast message
Toast.makeText(PostActivity.this, "Post Uploaded",
Toast.LENGTH_SHORT).show();
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent imageIntent) {
super.onActivityResult(requestCode, resultCode, imageIntent);
if (resultCode == RESULT_OK) {
if (requestCode == SELECT_PHOTO) {
//Get the URI
final boolean isCamera;
if (imageIntent == null) {
isCamera = true;
} else {
final String action = imageIntent.getAction();
if (action == null) {
isCamera = false;
} else {
isCamera = action.equals(MediaStore.ACTION_IMAGE_CAPTURE);
}
}
Uri selectedImageUri;
if (isCamera) {
selectedImageUri = uploadFileUri;
} else {
selectedImageUri = imageIntent == null ? null : imageIntent.getData();
}
//Get the Bitmap from the URI, and set it to the ImageView
try {
imageStream = getContentResolver().openInputStream(selectedImageUri);
final Bitmap selectedImage = BitmapFactory.decodeStream(imageStream);
imgPreview.setImageBitmap(selectedImage);
btnUploadPost.setEnabled(true);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
}
}
}
Vous obtenez une exception de pointeur null car bitmap est null. Remplace la ligne qui va
bitmap = BitmapFactory.decodeResource(getResources(), R.id.imgPreview);
avec ça
bitmap = ((BitmapDrawable) imgPreview.getDrawable()).getBitmap();
si vous utilisez le format PNG, votre image ne sera pas compressée, car le format PNG est un format sans perte. utilisez JPEG pour compresser votre image et utilisez 0 au lieu de 100 en qualité.
puis utiliser
Bitmap decoded = BitmapFactory.decodeStream(new ByteArrayInputStream(stream.toByteArray()));
Une erreur peut se produire lorsque bitmap est null.
Declare Bitmap bitmap; en tant que variable globale.
Et utilisez l'objet bitmap dans votre méthode onActivityResult .
Essayez d’utiliser Bitmap.createScaledBitmap
Bitmap.createScaledBitmap(Bitmap src, int dstWidth, int dstHeight, boolean filter);