如何在 Android 中实时检索 Firebase 中的图像？

Question

我有这个代码只检索一个图像。 我如何编辑它以检索更多图像？

以及如何将 URL 与图像附加在一起，以便如果用户单击图像 URL 将打开？

public class MainActivity extends AppCompatActivity {
    
    ImageView rImage;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        rImage = findViewById(R.id.rImage);

        FirebaseDatabase firebaseDatabase = FirebaseDatabase.getInstance();

        DatabaseReference databaseReference = firebaseDatabase.getReference();

        DatabaseReference getImage = databaseReference.child("image");

        getImage.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                
                String link = dataSnapshot.getValue(String.class);

                Picasso.get().load(link).into(rImage);
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
                // we are showing that error message in toast
                Toast.makeText(MainActivity.this, "Error Loading Image", Toast.LENGTH_SHORT).show();
            }
        });
    }
}

这是 XML 代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <!-- we are using ImageView for displaying image-->
    <ImageView
        android:id="@+id/rImage"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp" />

</LinearLayout>

Answer 1

首先在xml中添加一个按钮。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <!-- we are using ImageView for displaying image-->
    <ImageView
        android:id="@+id/rImage"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp" />
<Button
    android:id="@+id/btn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>
</LinearLayout>

现在通过该按钮onclick您将获得您的图像。

public class MainActivity extends AppCompatActivity {
    
    ImageView rImage;
    Button btn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        rImage = findViewById(R.id.rImage);
        //button reference
        btn= findViewById(R.id.btn);
        FirebaseDatabase firebaseDatabase = FirebaseDatabase.getInstance();

        DatabaseReference databaseReference = firebaseDatabase.getReference();

        DatabaseReference getImage = databaseReference.child("image");
        
        //setting onclick.
        btn.setOnClickListener(v -> {
             getImage.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                
                String link = dataSnapshot.getValue(String.class);

                Picasso.get().load(link).into(rImage);
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
                // we are showing that error message in toast
                Toast.makeText(MainActivity.this, "Error Loading Image", Toast.LENGTH_SHORT).show();
            }
        });
        });
       
    }
}

Answer 2

也许您可以尝试将ImageView更改为ImageButton ，这样您就可以拥有 ClickListener 和图像