ListView的优化及显示

最近做一个有聊天界面的应用，从服务器获取数据，显示有问题，如下图

这种错误真令人恶心，开始以为是优化代码搞出来的问题，仔细看了下，没问题，估计是缓存的问题，

布局代码如下：

<?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="match_parent"    android:orientation="vertical" >    <TableLayout        android:id="@+id/tl_item_send"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_margin="5dp"        android:padding="3dp"        android:shrinkColumns="0">        <TableRow            android:layout_width="0dp"            android:layout_height="wrap_content"            android:gravity="right|top"             >            <TextView                android:id="@+id/tv_item_send"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_marginLeft="50dp"                android:background="@drawable/conversion_send"                android:text="ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss疼啊蛋疼啊头也疼啊"                android:textColor="#000000"                android:textSize="18sp" />            <ImageView                android:id="@+id/iv_item_send"                android:layout_width="70dp"                android:layout_height="70dp"                android:layout_marginRight="10dp"                android:background="@drawable/account" />            <ImageView                android:id="@+id/iv_sendAvatar"                android:layout_width="45dp"                android:layout_height="45dp"                android:layout_marginRight="10dp"                android:layout_marginTop="10dp"                android:background="@drawable/circle_send" />        </TableRow>    </TableLayout>    <TableLayout        android:id="@+id/tl_item_receive"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_margin="5dp"        android:padding="3dp"            android:visibility="gone"        android:shrinkColumns="2">        <TableRow            android:layout_width="0dp"            android:layout_height="wrap_content"            android:gravity="left|top"             >            <ImageView                android:id="@+id/iv_receiverAvatar"                android:layout_width="45dp"                android:layout_height="45dp"                android:layout_marginRight="10dp"                android:background="@drawable/circle_send" />            <ImageView                android:id="@+id/iv_item_receive"                android:layout_width="70dp"                android:layout_height="70dp"                android:background="@drawable/account"/>            <TextView                android:id="@+id/tv_item_receiver"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_marginRight="50dp"                android:background="@drawable/conversion_receiver"                android:gravity="center_vertical"                android:text="ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss疼啊蛋疼啊头也疼啊"                android:textColor="#000000"                android:textSize="18sp"/>        </TableRow>    </TableLayout></LinearLayout>

BaseAadapter中的getView代码如下：

public View getView(int position, View convertView, ViewGroup parent) {View view;ViewHolder holder = null;if(convertView != null){view = convertView;holder = (ViewHolder) view.getTag();}else{view = View.inflate(context, R.layout.item_conversion_detail, null);holder = new ViewHolder();holder.tl_item_send = view.findViewById(R.id.tl_item_send);holder.tv_item_send = (TextView) view.findViewById(R.id.tv_item_send);holder.iv_sendAvatar = (ImageView) view.findViewById(R.id.iv_sendAvatar);holder.iv_item_send = (ImageView) view.findViewById(R.id.iv_item_send);holder.tl_item_receive = view.findViewById(R.id.tl_item_receive);holder.tv_item_receiver = (TextView) view.findViewById(R.id.tv_item_receiver);holder.iv_receiverAvatar = (ImageView) view.findViewById(R.id.iv_receiverAvatar);holder.iv_item_receive = (ImageView) view.findViewById(R.id.iv_item_receive);view.setTag(holder);}if(conservationList.get(position).getIsSend()){//若是发送的会话holder.tl_item_send.setVisibility(View.VISIBLE);if(conservationList.get(position).getIsTV()){//若会话内容是字符串holder.tv_item_send.setVisibility(View.VISIBLE);holder.iv_item_send.setVisibility(View.GONE);holder.tv_item_send.setText(position + ":"+ conservationList.get(position).getSendStr());}else{//若会话内容是图片holder.tv_item_send.setVisibility(View.GONE);holder.iv_item_send.setVisibility(View.VISIBLE);holder.iv_item_send.setBackgroundResource(R.drawable.consult);}//}else{//若是接收到的会话}else if(!conservationList.get(position).getIsSend()){//若是接收到的会话holder.tl_item_receive.setVisibility(View.VISIBLE);if(conservationList.get(position).getIsTV()){//若会话内容是字符串holder.tv_item_receiver.setVisibility(View.VISIBLE);holder.iv_item_receive.setVisibility(View.GONE);holder.tv_item_receiver.setText(position + ":"+ conservationList.get(position).getReceiveStr());}else{//若会话内容是图片holder.tv_item_receiver.setVisibility(View.GONE);holder.iv_item_receive.setVisibility(View.VISIBLE);holder.iv_item_receive.setBackgroundResource(R.drawable.consult);}}return view;}

其中ViewHolder是一个防止多次findViewById的类，以空间换时间的做法，代码：

static class ViewHolder{public View tl_item_send;public TextView tv_item_send;public ImageView iv_sendAvatar;public ImageView iv_item_send;public View tl_item_receive;public TextView tv_item_receiver;public ImageView iv_receiverAvatar;public ImageView iv_item_receive;}

后来发现是省懒劲，以为布局中为每个view设置了visibility=gone在代码中就不必要再某些地方加代码xxx.setVisibility(View.GONE);了，其实这一句是非常重要的，不然当在某一个地方让这个view显示后，缓存中就存有这个效果，然后会莫名其妙的在其他地方出现了这个效果，令人蛋疼。。。

将getView的代码稍微加上几句看似紧要的代码即可正常：

public View getView(int position, View convertView, ViewGroup parent) {View view;ViewHolder holder = null;if(convertView != null){view = convertView;holder = (ViewHolder) view.getTag();}else{view = View.inflate(context, R.layout.item_conversion_detail, null);holder = new ViewHolder();holder.tl_item_send = view.findViewById(R.id.tl_item_send);holder.tv_item_send = (TextView) view.findViewById(R.id.tv_item_send);holder.iv_sendAvatar = (ImageView) view.findViewById(R.id.iv_sendAvatar);holder.iv_item_send = (ImageView) view.findViewById(R.id.iv_item_send);holder.tl_item_receive = view.findViewById(R.id.tl_item_receive);holder.tv_item_receiver = (TextView) view.findViewById(R.id.tv_item_receiver);holder.iv_receiverAvatar = (ImageView) view.findViewById(R.id.iv_receiverAvatar);holder.iv_item_receive = (ImageView) view.findViewById(R.id.iv_item_receive);view.setTag(holder);}if(conservationList.get(position).getIsSend()){//若是发送的会话holder.tl_item_send.setVisibility(View.VISIBLE); holder.tl_item_receive.setVisibility(View.GONE);if(conservationList.get(position).getIsTV()){//若会话内容是字符串holder.tv_item_send.setVisibility(View.VISIBLE);holder.iv_item_send.setVisibility(View.GONE);holder.tv_item_send.setText(position + ":"+ conservationList.get(position).getSendStr());}else{//若会话内容是图片holder.tv_item_send.setVisibility(View.GONE);holder.iv_item_send.setVisibility(View.VISIBLE);holder.iv_item_send.setBackgroundResource(R.drawable.consult);}//}else{//若是接收到的会话}else if(!conservationList.get(position).getIsSend()){//若是接收到的会话 holder.tl_item_send.setVisibility(View.GONE);holder.tl_item_receive.setVisibility(View.VISIBLE);if(conservationList.get(position).getIsTV()){//若会话内容是字符串holder.tv_item_receiver.setVisibility(View.VISIBLE);holder.iv_item_receive.setVisibility(View.GONE);holder.tv_item_receiver.setText(position + ":"+ conservationList.get(position).getReceiveStr());}else{//若会话内容是图片holder.tv_item_receiver.setVisibility(View.GONE);holder.iv_item_receive.setVisibility(View.VISIBLE);holder.iv_item_receive.setBackgroundResource(R.drawable.consult);}}return view;}

正常显示：