[英]React Native Unable to resolve "firebase" from "firebase.js"
[英]Unable to resolve symbol storageRef in firebase
我正在使用 fire base 来存储图像,因为我在存储中遇到错误 Ref 无法解析符号,请帮忙。
public class Sample extends Activity {
public static final String GridViewDemo_ImagePath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/Pencilrulerlearner/";
StorageReference riversRef;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
File targetDirector = new File(GridViewDemo_ImagePath);
File[] files = targetDirector.listFiles();
for (File file1 : files) {
Uri file= Uri.fromFile(file1);
storageRef.child("images/" + file.getLastPathSegment());
UploadTask uploadTask = riversRef.putFile(file);
uploadTask.addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception exception) {
// Handle unsuccessful uploads
}
}).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
@Override
public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
// taskSnapshot.getMetadata() contains file metadata such as size, content-type, and download URL.
Uri downloadUrl = taskSnapshot.getDownloadUrl();
}
});
}
}
}
即使我将 storageRef 更改为riversRef ,我也收到以下错误
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.firebase.storage.StorageReference com.google.firebase.storage.StorageReference.child(java.lang.String)' on a null object reference
at nidhinkumar.firebaseexample.Sample.onCreate(Sample.java:31)
at android.app.Activity.performCreate(Activity.java:6092)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1112)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2468)
您收到此错误是因为storageRef
变量尚未初始化。 任何对null
引用调用方法的尝试都将导致java.lang.NullPointerException
。
在您的情况下,您应该首先获得对FirebaseStorage
实例的引用:
FirebaseStorage storage = FirebaseStorage.getInstance();
然后,您可以通过getReferenceFromUrl
方法获取对所需存储的引用。
StorageReference storageRef = storage.getReferenceFromUrl("Url to storage");
以下storageRef
被storageRef
并可以使用。
变量storageRef
未初始化。
首先,创建一个FirebaseStorage
变量:
storage = FirebaseStorage.getInstance();
然后像这样初始化StorageReference
类型变量storageRef
:
storageRef = storage.getReference();
StorageReference storageReference = FirebaseStorage.getInstance().getReference();
做一个简单的事情导入这个文件
import com.google.firebase.storage.StorageReference
;
欢迎您:)
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