自定义布局DynamicGridLayout优化

app/src/main/java/cn/yunliyunwai/beyondclouds/view/DynamicGridLayout.java

 package cn.yunliyunwai.beyondclouds.view;
 
 import android.content.Context;
+import android.graphics.drawable.BitmapDrawable;
 import android.os.Build;
 import android.util.AttributeSet;
 import android.view.ViewGroup;
 import android.widget.ImageView;
 
+import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 
 import com.bumptech.glide.Glide;
 import com.bumptech.glide.Priority;
+import com.bumptech.glide.RequestBuilder;
+import com.bumptech.glide.load.DataSource;
 import com.bumptech.glide.load.engine.DiskCacheStrategy;
+import com.bumptech.glide.load.engine.GlideException;
+import com.bumptech.glide.request.RequestListener;
 import com.bumptech.glide.request.RequestOptions;
+import com.bumptech.glide.request.target.Target;
 
 import java.util.List;
 
@@ -26,6 +33,8 @@ public class DynamicGridLayout extends ViewGroup {
     private int mCol;
     private int mSpacing;
     List<String> mImgUrls;
+    private boolean isImageInit;
+
 
 
     public DynamicGridLayout(Context context) {
@@ -54,7 +63,32 @@ public class DynamicGridLayout extends ViewGroup {
 
     @Override
     protected void onLayout(boolean changed, int l, int t, int r, int b) {
+        if (!isImageInit) {
+            initImages();
+        }
+    }
+
+    private int computePosition(int directionIndex, int imageSize) {
+        return (imageSize + mSpacing) * directionIndex;
+    }
+
+    public void setImages(List<String> imgUrls) {
+        removeAllViewsInLayout();
+        this.mImgUrls = imgUrls;
+        LayoutParams layoutParams = getLayoutParams();
+        isImageInit = false;
+
+        if (!hasImages()) {
+            layoutParams.height = 0;
+            setLayoutParams(layoutParams);
+            return;
+        }
+
+        initGridParams();
+        requestLayout();
+    }
 
+    private void initImages() {
         if (!hasImages()) {
             return;
         }
@@ -64,6 +98,11 @@ public class DynamicGridLayout extends ViewGroup {
 
         // 每个图片的尺寸
         int imageSize = (maxWidth - (mCol - 1) * mSpacing) / mCol;
+
+        if (getImageCount() == 1) {
+            imageSize = (int) (imageSize * 0.66);
+        }
+
         int layoutHeight = imageSize * mRow + (mRow - 1) * mSpacing;
 
         LayoutParams layoutParams = getLayoutParams();
@@ -75,40 +114,51 @@ public class DynamicGridLayout extends ViewGroup {
         for (int i = 0; i < mImgUrls.size(); i++) {
             currentRow = i / mCol;
             currentCol = i - (currentRow * mCol);
-            ImageView imageView = new ImageView(this.getContext());
-            RequestOptions options = new RequestOptions()
-                    .centerCrop()
-                    .placeholder(R.drawable.placeholder_square)
-                    .error(R.drawable.placeholder_square)
-                    .priority(Priority.HIGH)
-                    .diskCacheStrategy(DiskCacheStrategy.AUTOMATIC);
-            Glide.with(this).load(mImgUrls.get(i)).apply(options).into(imageView);
+            ImageView imageView = createImageView(mImgUrls.get(i));
             this.addView(imageView, new LayoutParams(imageSize, imageSize));
             int left = computePosition(currentCol, imageSize);
             int top = computePosition(currentRow, imageSize);
-            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
             imageView.layout(left, top, left + imageSize, top + imageSize);
         }
+        isImageInit = true;
     }
 
-    private int computePosition(int directionIndex, int imageSize) {
-        return (imageSize + mSpacing) * directionIndex;
-    }
-
-    public void setImages(List<String> imgUrls) {
-        removeAllViewsInLayout();
-        this.mImgUrls = imgUrls;
-        LayoutParams layoutParams = getLayoutParams();
+    private ImageView createImageView(String imgUrl) {
 
-        if (!hasImages()) {
-            layoutParams.height = 0;
-            setLayoutParams(layoutParams);
-            return;
+        ImageView imageView = new ImageView(this.getContext());
+        if (getImageCount() == 1) {
+            imageView.setScaleType(ImageView.ScaleType.FIT_START);
+        } else {
+            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
         }
 
-
-        initGridParams();
-        requestLayout();
+        RequestOptions options = new RequestOptions()
+                .placeholder(R.drawable.placeholder_square)
+                .error(R.drawable.placeholder_square)
+                .priority(Priority.HIGH)
+                .diskCacheStrategy(DiskCacheStrategy.AUTOMATIC);
+        RequestBuilder builder = Glide.with(this).load(imgUrl).apply(options);
+        if (getImageCount() == 1) {
+            builder.addListener(new RequestListener() {
+                @Override
+                public boolean onLoadFailed(@Nullable GlideException e, Object model, Target target, boolean isFirstResource) {
+                    return false;
+                }
+
+                @Override
+                public boolean onResourceReady(Object resource, Object model, Target target, DataSource dataSource, boolean isFirstResource) {
+                    if (resource instanceof BitmapDrawable) {
+                        LayoutParams layoutParams = getLayoutParams();
+                        layoutParams.height = ((BitmapDrawable) resource).getBitmap().getHeight();
+                        setLayoutParams(layoutParams);
+                    }
+
+                    return false;
+                }
+            });
+        }
+        builder.into(imageView);
+        return imageView;
     }
 
     /**

app/src/main/res/layout/swipe_refresh_list.xml

@@ -15,7 +15,6 @@
 
         <androidx.recyclerview.widget.RecyclerView
             android:id="@+id/recycler_view"
-            app:fastScrollEnabled="false"
             android:layout_width="match_parent"
             android:layout_height="match_parent"
             android:scrollbars="vertical" />