Android:如何在listView中设置特定行的背景,而不更改以前的条目
我正在尝试制作一个聊天程序。我的问题是,每当背景图像更新(发送方更改)时,数组中的每个项都会获得相同的背景。我如何改变这一点,使传出的消息获得一种背景,而传入的消息获得另一种背景Android:如何在listView中设置特定行的背景,而不更改以前的条目,android,android-listview,baseadapter,Android,Android Listview,Baseadapter,我正在尝试制作一个聊天程序。我的问题是,每当背景图像更新(发送方更改)时,数组中的每个项都会获得相同的背景。我如何改变这一点,使传出的消息获得一种背景,而传入的消息获得另一种背景 public class RowAdapter extends BaseAdapter { private Context context; private int textViewResourceId; private final ArrayList<String> messageList; p
public class RowAdapter extends BaseAdapter {
private Context context;
private int textViewResourceId;
private final ArrayList<String> messageList;
private final ArrayList<String> senderList;
public String messageDirection;
boolean out;
public RowAdapter(Context context, int textViewResourceId, ArrayList<String> messageList, ArrayList<String> senderList) {
super();
this.textViewResourceId = textViewResourceId;
this.messageList = messageList;
this.senderList = senderList;
this.context = context;
}
@Override
public View getView(int position, View convertView, ViewGroup parent){
View rowView = convertView;
ViewHolder holder;
long timestamp = System.currentTimeMillis();
String readableTimestamp = (String)DateUtils.getRelativeTimeSpanString(timestamp);
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
rowView = inflater.inflate(textViewResourceId, parent, false);
holder = new ViewHolder();
holder.label = (TextView)rowView.findViewById(R.id.label);
holder.message=(TextView)rowView.findViewById(R.id.message);
holder.time = (TextView)rowView.findViewById(R.id.textTime);
holder.RL = (RelativeLayout)rowView.findViewById(R.id.userAndMessage);
rowView.setTag(holder);
}else{
holder = (ViewHolder)rowView.getTag();
}
holder.label.setText(senderList.get(position));
holder.message.setText(messageList.get(position));
holder.time.setText(readableTimestamp);
if(out){
if (messageList.get(position)!= null) {
holder.RL.setBackgroundResource(R.drawable.yellow);
((RelativeLayout) rowView).setGravity(Gravity.RIGHT);
}
}else{
if (messageList.get(position)!= null) {
holder.RL.setBackgroundResource(R.drawable.green);
((RelativeLayout) rowView).setGravity(Gravity.LEFT);
}
}
return rowView;
}
public void setOut(boolean out){
this.out = out;
}
static class ViewHolder{
RelativeLayout RL;
TextView label;
TextView message;
TextView time;
}
@Override
public int getCount() {
return messageList.size();
}
@Override
public Object getItem(int position) {
return position;
}
@Override
public long getItemId(int position) {
return position;
}
}
公共类RowAdapter扩展了BaseAdapter{
私人语境;
私有int textViewResourceId;
私有最终ArrayList消息列表;
私有最终数组列表发送者列表;
公共字符串消息方向;
布尔输出;
公共行适配器(上下文上下文、int textViewResourceId、ArrayList消息列表、ArrayList发送者列表){
超级();
this.textViewResourceId=textViewResourceId;
this.messageList=messageList;
this.senderList=senderList;
this.context=上下文;
}
@凌驾
公共视图getView(int位置、视图转换视图、视图组父级){
视图行视图=转换视图;
视窗座;
长时间戳=System.currentTimeMillis();
String readableTimestamp=(String)DateUtils.getRelativeTimeSpanString(timestamp);
if(convertView==null){
LayoutFlater充气器=(LayoutFlater)context.getSystemService(context.LAYOUT\u充气器\u服务);
rowView=充气机。充气(textViewResourceId,父项,false);
holder=新的ViewHolder();
holder.label=(TextView)rowView.findViewById(R.id.label);
holder.message=(TextView)rowView.findViewById(R.id.message);
holder.time=(TextView)rowView.findViewById(R.id.textTime);
holder.RL=(RelativeLayout)rowView.findViewById(R.id.userAndMessage);
rowView.setTag(支架);
}否则{
holder=(ViewHolder)rowView.getTag();
}
holder.label.setText(senderList.get(position));
holder.message.setText(messageList.get(position));
holder.time.setText(可读时间戳);
如果(出){
if(messageList.get(position)!=null){
支架。右后立根资源(右可抽出。黄色);
((RelativeLayout)行视图).setGravity(Gravity.RIGHT);
}
}否则{
if(messageList.get(position)!=null){
支架.右后退避地面资源(右后退避.绿色);
((RelativeLayout)行视图)。设置重力(重力。左);
}
}
返回行视图;
}
公共空白放样(布尔值放样){
this.out=out;
}
静态类视窗夹{
相对寿命;
文本视图标签;
文本视图消息;
文本查看时间;
}
@凌驾
public int getCount(){
返回messageList.size();
}
@凌驾
公共对象getItem(int位置){
返回位置;
}
@凌驾
公共长getItemId(int位置){
返回位置;
}
}
好的,尝试这样做
这只是一个示例,您必须在其中添加流程
主布局xml
现在,像这样对主活动进行一些更改
import java.util.ArrayList;
导入android.app.Activity;
导入android.graphics.Color;
导入android.os.Bundle;
导入android.view.LayoutInflater;
导入android.view.Menu;
导入android.view.view;
导入android.view.ViewGroup;
导入android.widget.BaseAdapter;
导入android.widget.ListView;
导入android.widget.TextView;
公共类MainActivity扩展了活动{
private ArrayList items=new ArrayList();
ListView ListView_聊天;
自定义适配器;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
适配器=新的CustomAdapter(项目);
listView\u chat=(listView)findViewById(R.id.listView\u chat);
listView_chat.setAdapter(适配器);
}
@凌驾
公共布尔onCreateOptions菜单(菜单){
//为菜单充气;这会将项目添加到操作栏(如果存在)。
getMenuInflater().充气(R.menu.main,menu);
返回true;
}
MEBT的公共无效(视图五){
ChatObject对象=新的ChatObject(“来自我:)”,0);
添加(对象);
adapter.notifyDataSetChanged();
listView_chat.setSelection(items.size());
}
其他BT的公共无效(视图五){
ChatObject对象=新的ChatObject(“来自其他:)”,1);
添加(对象);
adapter.notifyDataSetChanged();
listView_chat.setSelection(items.size());
}
类CustomAdapter扩展了BaseAdapter{
数组列表项;
公共CustomAdapter(ArrayList项){
//TODO自动生成的构造函数存根
这个项目=项目;
}
@凌驾
public int getCount(){
//TODO自动生成的方法存根
返回items.size();
}
@凌驾
公共对象getItem(int位置){
//TODO自动生成的方法存根
返回项目。获取(位置);
}
@凌驾
公共长getItemId(int位置){
//TODO自动生成的方法存根
返回0;
}
@凌驾
公共视图getView(int位置、视图转换视图、视图组父视图){
//TODO自动生成的方法存根
convertView=LayoutInflater.from(parent.getContext()).flate(R.layout.row\u chat,null);
TextView txt_chat=(TextView)convertView.findViewById(R.id.txt_chat);
ChatObject对象=items.get(位置);
txt_chat.setText(object.getMssg());
if(object.getFrom()==0){
convertView.setBackgroundColor(颜色:蓝色);
}否则{
convertView.setBackgroundColor(Color.CYAN);
}
返回视图;
}
}
}
就是这样,如果您想更改xml布局中的填充或将其添加到dimens.xml文件中
<resources>
<!-- Default screen margins, per the Android Design guidelines. -->
<dimen name="activity_horizontal_margin">16dp</dimen>
<dimen name="activity_vertical_margin">16dp</dimen>
</resources>
16dp
16dp
现在快乐吗?我希望这对您有所帮助您是否找到了解决问题的方法??
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin" >
<TextView
android:id="@+id/txt_chat"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
public class ChatObject {
private String mssg;
private int from;
public ChatObject(String mssg, int from) {
super();
this.mssg = mssg;
this.from = from;
}
public String getMssg() {
return mssg;
}
public void setMssg(String mssg) {
this.mssg = mssg;
}
public int getFrom() {
return from;
}
public void setFrom(int from) {
this.from = from;
}
}
import java.util.ArrayList;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
public class MainActivity extends Activity {
private ArrayList<ChatObject> items = new ArrayList<ChatObject>();
ListView listView_chat;
CustomAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
adapter = new CustomAdapter(items);
listView_chat = (ListView) findViewById(R.id.listView_Chat);
listView_chat.setAdapter(adapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public void fromMeBt(View v) {
ChatObject object = new ChatObject("from me :)", 0);
items.add(object);
adapter.notifyDataSetChanged();
listView_chat.setSelection(items.size());
}
public void fromOtherBt(View v) {
ChatObject object = new ChatObject("from other :)", 1);
items.add(object);
adapter.notifyDataSetChanged();
listView_chat.setSelection(items.size());
}
class CustomAdapter extends BaseAdapter {
ArrayList<ChatObject> items;
public CustomAdapter(ArrayList<ChatObject> items) {
// TODO Auto-generated constructor stub
this.items = items;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return items.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return items.get(position);
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
convertView = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_chat, null);
TextView txt_chat = (TextView) convertView.findViewById(R.id.txt_chat);
ChatObject object = items.get(position);
txt_chat.setText(object.getMssg());
if (object.getFrom() == 0) {
convertView.setBackgroundColor(Color.BLUE);
}else {
convertView.setBackgroundColor(Color.CYAN);
}
return convertView;
}
}
}
<resources>
<!-- Default screen margins, per the Android Design guidelines. -->
<dimen name="activity_horizontal_margin">16dp</dimen>
<dimen name="activity_vertical_margin">16dp</dimen>
</resources>