Added image view hints

app/src/main/java/eu/faircode/email/ViewImageHint.java

@@ -0,0 +1,60 @@
+package eu.faircode.email;
+
+import android.content.Context;
+import android.text.TextUtils;
+import android.util.AttributeSet;
+import android.view.Gravity;
+import android.view.View;
+import android.widget.Toast;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.appcompat.widget.AppCompatImageView;
+
+public class ViewImageHint extends AppCompatImageView implements View.OnLongClickListener {
+    private OnLongClickListener listener;
+
+    public ViewImageHint(@NonNull Context context) {
+        super(context);
+        setOnLongClickListener(this);
+    }
+
+    public ViewImageHint(@NonNull Context context, @Nullable AttributeSet attrs) {
+        super(context, attrs);
+        setOnLongClickListener(this);
+    }
+
+    public ViewImageHint(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+        setOnLongClickListener(this);
+    }
+
+    @Override
+    public void setOnLongClickListener(OnLongClickListener listener) {
+        if (listener == this) {
+            super.setOnLongClickListener(listener);
+            return;
+        }
+
+        this.listener = listener;
+    }
+
+    @Override
+    public boolean onLongClick(View v) {
+        if (listener == null || !listener.onLongClick(v)) {
+            String title = getContentDescription().toString();
+            if (!TextUtils.isEmpty(title)) {
+                int[] pos = new int[2];
+                getLocationInWindow(pos);
+
+                Toast toast = ToastEx.makeText(getContext(), title, Toast.LENGTH_LONG);
+                toast.setGravity(Gravity.TOP | Gravity.START, pos[0], pos[1]);
+                toast.show();
+
+                return true;
+            }
+        }
+
+        return false;
+    }
+}