ListView Viewholder的坑 线性布局的坑

1。ListView Viewholder的坑

    /**
     * 默认带图片的menu adapter
     */
    public static class MenuImageAdapter extends BaseAdapter {
        private List<Aliquot> mDataSet;
        private Context mContext;

        public MenuImageAdapter(List<Aliquot> dataSet, Context context) {
            this.mDataSet = dataSet;
            this.mContext = context;
        }

        @Override
        public int getCount() {
            return mDataSet == null ? 0 : mDataSet.size();
        }

        @Override
        public Object getItem(int position) {
            return mDataSet.get(position);
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            MenuImageHolder holder = null;
            Aliquot aliquot = mDataSet.get(position);
            if (convertView == null) {
                holder = new MenuImageHolder();
                convertView = LayoutInflater.from(mContext).inflate(DEF_TEXT_IMAGE_ITEM_RES, null);
                holder.mImageViewLeft = (ImageView) convertView.findViewById(R.id.img_menu_dialog_left);
                holder.mImageViewRight = (ImageView) convertView.findViewById(R.id.img_menu_dialog_right);
                holder.mParentRl = (RelativeLayout) convertView.findViewById(R.id.dialog_menu_parent_rl);
                holder.mTextView = (TextView) convertView.findViewById(R.id.tv_menu_dialog);
                holder.mVline = (View) convertView.findViewById(R.id.shelf_dilog_item_v_line);
                convertView.setTag(holder);
            } else {
                holder = (MenuImageHolder) convertView.getTag();
            }
            if (aliquot.mSrcLeftDrawableId != 0) {
                holder.mImageViewLeft.setImageResource(aliquot.mSrcLeftDrawableId);
                holder.mImageViewLeft.setVisibility(View.VISIBLE);
                LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) holder.mParentRl.getLayoutParams();
                params.setMargins(15,0,0,0);
            }else{
                holder.mImageViewLeft.setVisibility(View.GONE);
            }

            if (aliquot.mSrcRightDrawableId != 0) {
                holder.mImageViewRight.setImageResource(aliquot.mSrcRightDrawableId);
                holder.mImageViewRight.setVisibility(View.VISIBLE);
            }else{
                holder.mImageViewRight.setVisibility(View.GONE);
            }

//            if(position == mDataSet.size()-1){
//                holder.mVline.setVisibility(View.INVISIBLE);
//            }else{
//                holder.mVline.setVisibility(View.VISIBLE);
//            }
            holder.mTextView.setText(aliquot.mContent);
            return convertView;
        }
    }

    public static class MenuImageHolder {
        private TextView mTextView;//文字
        private ImageView mImageViewLeft;//图片在左侧
        private ImageView mImageViewRight;//图片在右侧
        private RelativeLayout mParentRl;
        private View mVline;//分割线
    }

其中：

if (aliquot.mSrcLeftDrawableId != 0) {
                holder.mImageViewLeft.setImageResource(aliquot.mSrcLeftDrawableId);
                holder.mImageViewLeft.setVisibility(View.VISIBLE);
                LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) holder.mParentRl.getLayoutParams();
                params.setMargins(15,0,0,0);
            }else{
                holder.mImageViewLeft.setVisibility(View.GONE);
            }

如果这里没有else的话，就会导致你的holder.mImageViewLeft 显示出来。因为你holder重用了嘛，用了holder之后，记得改状态。

2。线性布局的坑

水平线性布局如果被其中一个元素布满了（match_paraent），那么你写的后面的元素都不会显示出来了。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="@dimen/dialog_menutype_item_height"
    android:gravity="center_vertical"
    android:paddingLeft="@dimen/dialog_padding_left"
    android:orientation="horizontal">

    <ImageView
        android:id="@+id/img_menu_dialog_left"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         />

    <RelativeLayout
        android:id="@+id/dialog_menu_parent_rl"
        android:layout_width="match_parent"
        android:layout_height="@dimen/dialog_menutype_item_height"
        android:layout_marginLeft="15dp"
        >

        <TextView
            android:id="@+id/tv_menu_dialog"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerVertical="true"
            android:textSize="15sp"
            android:textColor="@color/primary_color_1"
             />

        <View
            android:id="@+id/shelf_dilog_item_v_line"
            android:layout_width="match_parent"
            android:layout_height="2px"
            android:visibility="gone"
            android:layout_alignParentBottom="true"
            android:background="@color/zz_black_10_percent_transparent"
            ></View>

    </RelativeLayout>

    <ImageView
        android:id="@+id/img_menu_dialog_right"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />

</LinearLayout>

这个布局中id 为img_menu_dialog_right的元素永远也显示不出来。坑死我了，我开始没有意识到这个简单的问题。