为preview_image添加单击事件，随机改变容器背景色

- 为preview_image的父级LinearLayout添加id标识(preview_image_container)
- 实现单击preview_image时随机生成颜色并改变容器背景
- 添加必要的import语句(LinearLayout, Random)

gallery/src/main/java/cc/winboll/studio/gallery/CropActivity.java

@@ -19,6 +19,7 @@ import android.widget.ImageView;
 import android.widget.ScrollView;
 import android.widget.SeekBar;
 import android.widget.TextView;
+import android.widget.LinearLayout;
 import android.widget.Toast;
 import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.app.AppCompatActivity;
@@ -26,6 +27,7 @@ import cc.winboll.studio.libappbase.LogUtils;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.util.Random;
 
 public class CropActivity extends AppCompatActivity {
     public static final String TAG = "CropActivity";
@@ -310,10 +312,18 @@ public class CropActivity extends AppCompatActivity {
         View dialogView = getLayoutInflater().inflate(R.layout.dialog_crop_info, null);
         TextView infoText = dialogView.findViewById(R.id.info_text);
         ImageView previewImage = dialogView.findViewById(R.id.preview_image);
+        LinearLayout previewImageContainer = dialogView.findViewById(R.id.preview_image_container);
         infoText.setText(info.toString());
         if (previewBitmap != null) {
             previewImage.setImageBitmap(previewBitmap);
         }
+        previewImage.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                int randomColor = 0xFF000000 | new Random().nextInt(0x00FFFFFF);
+                previewImageContainer.setBackgroundColor(randomColor);
+            }
+        });
         
         AlertDialog dialog = new AlertDialog.Builder(this)
             .setTitle("裁剪信息")