要实现Android的BottomSheet覆盖一半的锚定ImageView，可以按照以下步骤进行操作：

1. 在XML布局文件中添加ImageView和BottomSheet控件：

2. 在Activity或Fragment中使用BottomSheetBehavior控制BottomSheet的显示和隐藏：

import com.google.android.material.bottomsheet.BottomSheetBehavior;

public class YourActivity extends AppCompatActivity {
    private BottomSheetBehavior bottomSheetBehavior;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.your_layout);

        // 获取BottomSheet控件
        LinearLayout bottomSheetLayout = findViewById(R.id.bottomSheetLayout);

        // 设置BottomSheet的最大高度为屏幕高度的一半
        int screenHeight = getResources().getDisplayMetrics().heightPixels;
        ViewGroup.LayoutParams layoutParams = bottomSheetLayout.getLayoutParams();
        layoutParams.height = screenHeight / 2;
        bottomSheetLayout.setLayoutParams(layoutParams);

        // 初始化BottomSheetBehavior
        bottomSheetBehavior = BottomSheetBehavior.from(bottomSheetLayout);
        bottomSheetBehavior.setHideable(true);
        bottomSheetBehavior.setPeekHeight(layoutParams.height);
        bottomSheetBehavior.setState(BottomSheetBehavior.STATE_HIDDEN);

        // 设置ImageView的点击事件，点击时显示/隐藏BottomSheet
        ImageView anchorImageView = findViewById(R.id.anchorImageView);
        anchorImageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (bottomSheetBehavior.getState() == BottomSheetBehavior.STATE_HIDDEN) {
                    bottomSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
                } else {
                    bottomSheetBehavior.setState(BottomSheetBehavior.STATE_HIDDEN);
                }
            }
        });
    }
}

通过上述代码，当点击ImageView时，BottomSheet会从底部滑动出现覆盖一半的锚定ImageView，再次点击ImageView时，BottomSheet会滑动回底部隐藏起来。