我从数据库中获取数据并将其推送到ListView以查看所有数据。
在我的ListView中，我还有一个带有文字“Like”的TextView。现在，当我单击相同的文本时，它将更改为“Liked”，并且我正在更新我在数据库中的状态。
现在我的问题是，当我点击“赞”文字时，文字会变为“喜欢”，并且会在数据库中更新。但是当我滚动列表视图时，我可以注意到其他列表'喜欢的文字也被改为喜欢。我不确定出了什么问题。
我一直试图解决这个问题很多天但没有成功。
这是我的适配器代码。在底部，您可以看到我的onClickListener for textview
package com.mytestapp.myapp;
import java.net.URI;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebView;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ImageButton;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class ForumAdapter extends ArrayAdapter<DiscussionList> {
private static List<DiscussionList> items = null;
public ForumAdapter(Context context, List<DiscussionList> items) {
super(context, R.layout.custom_list, items);
this.items = items;
}
@Override
public int getCount() {
return items.size();
}
public static DiscussionList getModelPosition(int position) {
return items.get(position);
}
public void refill(List<DiscussionList> items) {
items.clear();
items.addAll(items);
notifyDataSetChanged();
}
public static class ViewHolder {
WebView mywebviewholder;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
View v = convertView;
if (v == null) {
LayoutInflater li = LayoutInflater.from(getContext());
v = li.inflate(R.layout.custom_list, null);
} else {
holder = (ViewHolder) convertView.getTag();
}
DiscussionList app = items.get(position);
if (app != null) {
TextView titleText = (TextView) v.findViewById(R.id.dscTitle);
TextView categoryText = (TextView) v.findViewById(R.id.dscCategory);
TextView descriptionText = (TextView) v
.findViewById(R.id.dscDescription);
TextView timeText = (TextView) v.findViewById(R.id.dscTime);
TextView idText = (TextView) v.findViewById(R.id.dscDiscId);
final TextView likeText = (TextView) v.findViewById(R.id.likeText1);
String like_Status = app.getLikeStatus();
titleText.setText(app.getTitle());
categoryText.setText(app.getCategory());
descriptionText.setText(app.getDescription());
timeText.setText(app.getTime());
idText.setText(app.getDiscId());
if (like_Status == "null") {
likeText.setText("Like");
} else {
likeText.setText("Liked");
}
final String dId = app.getDiscId();
// onClick for image button inside list view
likeText.setTag(new Integer(position));
likeText.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final Integer myposition = (Integer) view.getTag();
// Toast.makeText(getContext(), "" + dId,
// Toast.LENGTH_SHORT)
// .show();
likeText.setText("Liked");
MainActivity val = new MainActivity();
val.updateLikeTable(dId);
}
});
}
return v;
}
}
这也是我的MainActivity.java文件，我更新数据库中的喜欢
package com.mytestapp.myapp;
import java.net.URI;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ImageButton;
import android.widget.ListView;
import android.widget.Toast;
public class MainActivity extends ListActivity implements FetchDataListener {
public static String strTitle = "0", strCategory = "0",
strDescription = "0", strTime = "0", strDid = "0";
Collegemate_DB db = new Collegemate_DB(this);
int likeStatus = 1;
private ProgressDialog dialog;
public static String usId=null;
ImageButton imgButton;
List<DiscussionList> items = new ArrayList<DiscussionList>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list_forum_topics);
usId = db.getCurrentuserId();
initView();
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
.permitAll().build();
StrictMode.setThreadPolicy(policy);
}
/*
* On click listener to get values from DiscussionList class and send it
* to another activity when clicking on the list item
*/
ListView forumList = getListView();
forumList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// Get position of the clicked list item from adapter
String dTitle, dCategory, dDescription, dTime, dDid;
DiscussionList accessVar = ForumAdapter
.getModelPosition(position);
dTitle = accessVar.getTitle();
dCategory = accessVar.getCategory();
dDescription = accessVar.getDescription();
dTime = accessVar.getTime();
dDid = accessVar.getDiscId();
/*
* Storing the forum values in string and passing it to another
* activity
*/
String values[] = { dTitle, dCategory, dDescription, dTime,
dDid };
Intent i = new Intent(MainActivity.this, ForumFullView.class);
i.putExtra("sendData", values);
startActivity(i);
}
});
}
private void initView() {
// show progress dialog
Log.i("j","Inside Init");
dialog = ProgressDialog.show(this, "", "Loading...");
String url = "http://example.com/mypath/listData.php?currentUser_id="
+ usId;
Log.i("Fetch Url : ", url);
FetchDataTask task = new FetchDataTask(this);
task.execute(url);
}
@Override
public void onFetchComplete(List<DiscussionList> data) {
// dismiss the progress dialog
if (dialog != null)
dialog.dismiss();
// create new adapter
ListView forumList = getListView();
// set the adapter to list
ForumAdapter adapter = new ForumAdapter(this, data);
if (forumList.getAdapter() == null) {
//final ForumAdapter adapter = new ForumAdapter(this, data);
forumList.setAdapter(adapter);
} else {
((ForumAdapter) forumList.getAdapter()).refill(items);
}
// setListAdapter(adapter);
}
@Override
public void onFetchFailure(String msg) {
// dismiss the progress dialog
if (dialog != null)
dialog.dismiss();
// show failure message
Toast.makeText(this, msg, Toast.LENGTH_LONG).show();
}
public void updateLikeTable(String dId,List<DiscussionList> items) {
try {
String likeUrl = "http://example.com/mypath/createlike.php?discId="
+ dId + "&userId=" + usId + "&like_status=" + likeStatus;
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet();
request.setURI(new URI(likeUrl));
client.execute(request);
} catch (Exception e) {
e.printStackTrace();
}
}
}
感谢任何帮助。
提前致谢
答案 0 :(得分：1)
您遇到的问题是ListView窗口小部件可以回收其视图。一旦视图离开屏幕滚动，它就会进入垃圾堆，这样当新视图滚动到位时可以重复使用，而不是要求从头开始充气。该回收的视图是convertView方法中的getView()参数。首次填充ListView时，convertView将始终为空，因为垃圾堆中没有任何内容，因此您不得不强制新视图，但后续调用可能会有该参数为非空。
这样做的实际结果是，当点击的视图被设置为＆＃34;喜欢＆＃34;得到回收，TextView仍然存在，并且仍然填充了＃34;喜欢＆＃34;而不是推定的默认值＆＃34;喜欢＆＃34;。因此，如果您点击一个视图，然后向下滚动以使其离开屏幕，它会回来并导致您看到的错误。
您可能想要解决此问题的方法是每次根据数据库中的内容在likeText内设置getView()的文本。如果帖子已被喜欢，请将其设置为＆＃34; Liked＆＃34;，如果没有，请将其设置为＆＃34; Like＆＃34;。它应该只是一行，假设您可以轻松访问您的DiscussionList对象是否喜欢该帖子。
P.S。作为旁注，在Android中，硬编码的字符串通常不受欢迎，因此您可能希望移动您的＆＃34;喜欢＆＃34;字符串到资源文件中。除非您计划进行翻译，否则它确实是必要的，但它仍然是良好的做法。