java - 我得到一个由布尔位图引起的空指针
问题描述
我得到了这种空指针，原因是：java.lang.NullPointerException：尝试调用虚拟方法'boolean android.graphics.Bitmap.compress（android.graphics.Bitmap$CompressFormat，int，java.io.OutputStream）'在空对象引用上，这是我的日志猫
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.umo2.players, PID: 1771
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.umo2.players/com.umo2.players.Profile.AccountSettingsActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.graphics.Bitmap.compress(android.graphics.Bitmap$CompressFormat, int, java.io.OutputStream)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2868)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2958)
at android.app.ActivityThread.-wrap12(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1653)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6739)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:449)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.graphics.Bitmap.compress(android.graphics.Bitmap$CompressFormat, int, java.io.OutputStream)' on a null object reference
at com.umo2.players.Utils.ImageManager.getBytesFromBitmap(ImageManager.java:46)
at com.umo2.players.Utils.FirebaseMethods.uploadNewPhoto(FirebaseMethods.java:428)
at com.umo2.players.Profile.AccountSettingsActivity.getIncomingIntent(AccountSettingsActivity.java:90)
at com.umo2.players.Profile.AccountSettingsActivity.onCreate(AccountSettingsActivity.java:66)
at android.app.Activity.performCreate(Activity.java:7045)
at android.app.Activity.performCreate(Activity.java:7036)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1217)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2815)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2958)
at android.app.ActivityThread.-wrap12(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1653)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6739)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:449)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
这是我的图像管理器实用程序
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
public class ImageManager {
private static final String TAG = "ImageManager";
public static final int IMAGE_SAVE_QUALITY = 90;
public static Bitmap getBitmap(String imgUrl) {
File imageFile = new File(imgUrl);
FileInputStream fis = null;
Bitmap bitmap = null;
try {
fis = new FileInputStream(imageFile);
bitmap = BitmapFactory.decodeStream(fis);
} catch (FileNotFoundException e) {
Log.e(TAG, "getBitmap: FileNotFoundException: " + e.getMessage());
} finally {
try {
fis.close();
} catch (IOException e) {
Log.e(TAG, "getBitmap: FileNotFoundException: " + e.getMessage());
}
}
return bitmap;
}
/**
* return byte array from a bitmap
* quality is greater than 0 but less than 100
*
* @param bm
* @param quality
* @return
*/
public static byte[] getBytesFromBitmap(Bitmap bm, int quality){
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.JPEG, quality, stream);
return stream.toByteArray();
}
}
这是我的firebase方法
public void uploadNewPhoto(String photoType, final String caption,final int count, final String imgUrl,
Bitmap bm) {
Log.d(TAG, "uploadNewPhoto: attempting to uplaod new photo.");
FilePaths filePaths = new FilePaths();
if (photoType.equals(mContext.getString(R.string.new_photo))){
Log.d(TAG, "uploadNewPhoto: uploading NEW photo.");
String user_id = FirebaseAuth.getInstance().getCurrentUser().getUid();
StorageReference storageReference = mStorageReference
.child(filePaths.FIREBASE_IMAGE_STORAGE + "/" + user_id + "/photo" + (count + 1));
//convert image url to bitmap
if(bm == null){
bm = com.umo2.players.Utils.ImageManager.getBitmap(imgUrl);
}
byte[] bytes = ImageManager.getBytesFromBitmap(bm, 100);
UploadTask uploadTask = null;
uploadTask = storageReference.putBytes(bytes);
uploadTask.addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
@Override
public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
String firebaseUrl = Objects.requireNonNull(taskSnapshot.getMetadata().getReference()).getDownloadUrl().toString();
Toast.makeText(mContext, "photo upload success", Toast.LENGTH_SHORT).show();
//add the new photo to 'photos' node and 'user_photos' node
addPhotoToDatabase(caption, firebaseUrl.toString());
//navigate to the main feed so the user can see their photo
Intent intent = new Intent(mContext, HomeActivity.class);
mContext.startActivity(intent);
}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
Log.d(TAG, "onFailure: Photo upload failed.");
Toast.makeText(mContext, "Photo upload failed ", Toast.LENGTH_SHORT).show();
}
}).addOnProgressListener(new OnProgressListener<UploadTask.TaskSnapshot>() {
@Override
public void onProgress(UploadTask.TaskSnapshot taskSnapshot) {
double progress = (100 * taskSnapshot.getBytesTransferred()) / taskSnapshot.getTotalByteCount();
if(progress - 15 > mPhotoUploadProgress){
Toast.makeText(mContext, "photo upload progress: " + String.format("%.0f", progress) + "%", Toast.LENGTH_SHORT).show();
mPhotoUploadProgress = progress;
}
Log.d(TAG, "onProgress: upload progress: " + progress + "% done");
}
});
}
//case new profile photo
else if(photoType.equals(mContext.getString(R.string.profile_photo))){
Log.d(TAG, "uploadNewPhoto: uploading new PROFILE photo");
String user_id = FirebaseAuth.getInstance().getCurrentUser().getUid();
StorageReference storageReference = mStorageReference
.child(filePaths.FIREBASE_IMAGE_STORAGE + "/" + user_id + "/profile_photo");
//convert image url to bitmap
if(bm == null){
bm = com.umo2.players.Utils.ImageManager.getBitmap(imgUrl);
}
byte[] bytes = ImageManager.getBytesFromBitmap(bm, 100);
UploadTask uploadTask = null;
uploadTask = storageReference.putBytes(bytes);
uploadTask.addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
@Override
public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
String firebaseUrl = Objects.requireNonNull(taskSnapshot.getMetadata().getReference()).getDownloadUrl().toString();
Toast.makeText(mContext, "photo upload success", Toast.LENGTH_SHORT).show();
//insert into 'user_account_settings' node
setProfilePhoto(firebaseUrl.toString());
((AccountSettingsActivity)mContext).setViewPager(
((AccountSettingsActivity)mContext).pagerAdapter
.getFragmentNumber(mContext.getString(R.string.edit_profile_fragment))
);
}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
Log.d(TAG, "onFailure: Photo upload failed.");
Toast.makeText(mContext, "Photo upload failed ", Toast.LENGTH_SHORT).show();
}
}).addOnProgressListener(new OnProgressListener<UploadTask.TaskSnapshot>() {
@Override
public void onProgress(UploadTask.TaskSnapshot taskSnapshot) {
double progress = (100 * taskSnapshot.getBytesTransferred()) / taskSnapshot.getTotalByteCount();
if(progress - 15 > mPhotoUploadProgress){
Toast.makeText(mContext, "photo upload progress: " + String.format("%.0f", progress) + "%", Toast.LENGTH_SHORT).show();
mPhotoUploadProgress = progress;
}
Log.d(TAG, "onProgress: upload progress: " + progress + "% done");
}
});
}
}
最后是我的帐户设置活动
private void getIncomingIntent(){
Intent intent = getIntent();
if(intent.hasExtra(getString(R.string.selected_image))
|| intent.hasExtra(getString(R.string.selected_bitmap))){
//if there is an imageUrl attached as an extra, then it was chosen from the gallery/photo fragment
Log.d(TAG, "getIncomingIntent: New incoming imgUrl");
if(intent.getStringExtra(getString(R.string.return_to_fragment)).equals(getString(R.string.edit_profile_fragment))){
if(intent.hasExtra(getString(R.string.selected_image))){
//set the new profile picture
FirebaseMethods firebaseMethods = new FirebaseMethods(AccountSettingsActivity.this);
firebaseMethods.uploadNewPhoto(getString(R.string.profile_photo), null, 0,
intent.getStringExtra(getString(R.string.selected_image)), null);
}
else if(intent.hasExtra(getString(R.string.selected_bitmap))){
//set the new profile picture
FirebaseMethods firebaseMethods = new FirebaseMethods(AccountSettingsActivity.this);
firebaseMethods.uploadNewPhoto(getString(R.string.profile_photo), null, 0,
null,(Bitmap) intent.getParcelableExtra(getString(R.string.selected_bitmap)));
}
}
}
if(intent.hasExtra(getString(R.string.calling_activity))){
Log.d(TAG, "getIncomingIntent: received incoming intent from " + getString(R.string.profile_activity));
setViewPager(pagerAdapter.getFragmentNumber(getString(R.string.edit_profile_fragment)));
}
}
解决方案
firebaseMethods.uploadNewPhoto(getString(R.string.profile_photo), null, 0,
null,(Bitmap) intent.getParcelableExtra(getString(R.string.selected_bitmap)));
您将 imageUrl 作为 null 传递，这是您的第四个参数。所以 fis = new FileInputStream(imageFile); 将返回 null，这就是您收到 NullPointerException 的原因。
由于您已经从意图中获取位图作为可打包的额外内容，请将位图而不是 imageUrl 传递给您的 getBitmap 方法，这样您就有了：
getBitmap(Bitmap bitmap) {
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
if (bitmap != null) {
bitmap.compress(Bitmap.CompressFormat.JPEG, 80, bytes);
}
// At this point, you have a compressed bitmap.
}
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