如何在android中获取特定列表视图项目的ID?
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【中文标题】如何在android中获取特定列表视图项目的ID?【英文标题】:How to get id of particular item of listview in android? 【发布时间】:2015-01-22 02:25:53 【问题描述】:我正在使用Listview
并设置多个项目,每个项目都有赞、分享和评论选项。
实际上,我已经成功获取了项目 ID 以及 TextView
的 setText
。但无法在特定项目的 Like Button Click 事件中获取项目 ID。
如何在Button
点击事件中获取Listview
中每个项目的项目ID?
MyAdapter 类的演示:
public class Adapter1 extends BaseAdapter implements OnClickListener
public ArrayList<HashMap<String, String>> arr = null;
Context context = null;
LayoutInflater layoutInflater = null;
HashMap<String, String> getData = new HashMap<String, String>();
String urlLike = null;
TextView strId = null;
public NewsFeedAdapter(Context context,
ArrayList<HashMap<String, String>> arr)
this.context = context;
this.arr= arr;
layoutInflater = LayoutInflater.from(context);
@Override
public int getCount()
return arr.size();
@Override
public Object getItem(int position)
return arr.get(position);
@Override
public long getItemId(int position)
return position;
@Override
public View getView(int position, View convertView, ViewGroup parent)
ViewHolder viewHolder = null;
if (convertView == null)
convertView = layoutInflater.inflate(
R.layout.my_list_item, null);
/** initialize ViewHolder */
viewHolder = new ViewHolder();
/** Initialize Widgets */
/** Imageview */
viewHolder.imgLike = (ImageView) convertView
.findViewById(R.id.imgLike);
viewHolder.imgLike.setOnClickListener(this);
viewHolder.imgComments = (ImageView) convertView
.findViewById(R.id.imgComments);
viewHolder.imgComments.setOnClickListener(this);
viewHolder.imgShare = (ImageView) convertView
.findViewById(R.id.imgShare);
viewHolder.imgShare.setOnClickListener(this);
/** TextView */
viewHolder.txtId = (TextView) convertView
.findViewById(R.id.txtId);
viewHolder.txtDescription = (TextView) convertView
.findViewById(R.id.txtDescription);
getData = arr.get(position);
viewHolder.txtId.setText(getData
.get(Fragment1.TAG_ID));
viewHolder.txtDescription.setText(getData
.get(Fragment1.TAG_MESSAGE));
convertView.setTag(viewHolder);
else
viewHolder = (ViewHolder) convertView.getTag();
convertView.setOnClickListener(new OnClickListener()
@Override
public void onClick(View v)
);
return convertView;
/** ViewHolder Class */
public class ViewHolder
ImageView imgLike = null, imgComments = null,
imgShare = null;
TextView txtId = null,txtDescription = null;
@Override
public void onClick(View view)
switch (view.getId())
case R.id.imgLike:
strId = ((TextView) view
.findViewById(R.id.txtId));
System.out.println("On Click====="
+ strId.getText().toString());
urlLike = "http://www.example.com?id="
+ strId.getText().toString() + "&user_id="
+ myDetail.getUserId();
new sendLikeData().execute();
break;
case R.id.imgComments:
break;
case R.id.imgShare:
break;
default:
break;
public class sendLikeData extends AsyncTask<Void, Void, Void>
protected void onPreExecute()
super.onPreExecute();
@Override
protected Void doInBackground(Void... arg0)
ServiceHandler sh = new ServiceHandler();
String jsonStr = sh.makeServiceCall(urlLike, ServiceHandler.GET);
Log.d("Response : Like", ">" + jsonStr);
return null;
protected void onPostExecute(Void result)
super.onPostExecute(result);
;
OutPut is, NullPointer Exception in System.out.println("On Click====="
+ strId.getText().toString());.
xml文件是,
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/masterLayout"
android:layout_
android:layout_
android:layout_margin="@dimen/five_dp" >
<TextView
android:id="@+id/txtDescription"
android:layout_
android:layout_
android:layout_alignParentLeft="true"
android:layout_marginLeft="@dimen/ten_dp"
android:layout_marginRight="@dimen/ten_dp"
android:layout_marginTop="@dimen/ten_dp" />
<ImageView
android:id="@+id/imgImage"
android:layout_
android:layout_
android:layout_below="@+id/txtDescription"
android:layout_centerHorizontal="true"
android:layout_marginBottom="@dimen/ten_dp"
android:layout_marginLeft="@dimen/ten_dp"
android:layout_marginRight="@dimen/ten_dp"
android:layout_marginTop="@dimen/ten_dp"
android:background="@null"
android:contentDescription="@string/content_description"
android:src="@drawable/ic_launcher" />
<LinearLayout
android:layout_
android:layout_
android:layout_alignParentLeft="true"
android:layout_below="@+id/imgImage"
android:background="@drawable/strip"
android:baselineAligned="false"
android:gravity="center_vertical"
android:orientation="horizontal" >
<RelativeLayout
android:layout_
android:layout_
android:layout_weight="1" >
<ImageView
android:id="@+id/imgLike"
android:layout_
android:layout_
android:layout_centerHorizontal="true"
android:layout_centerInParent="true"
android:contentDescription="@string/content_description"
android:src="@drawable/like" />
<TextView
android:layout_
android:layout_
android:layout_alignTop="@+id/imgLike"
android:layout_toRightOf="@+id/imgLike"
android:background="@drawable/getbg"
android:gravity="center"
android:padding="@dimen/two_dp"
android:textColor="@color/white"
android:textSize="@dimen/ten_sp" />
</RelativeLayout>
<RelativeLayout
android:layout_
android:layout_
android:layout_weight="1" >
<ImageView
android:id="@+id/imgComments"
android:layout_
android:layout_
android:layout_centerHorizontal="true"
android:layout_centerInParent="true"
android:contentDescription="@string/content_description"
android:src="@drawable/comments" />
<TextView
android:layout_
android:layout_
android:layout_toRightOf="@+id/imgComments"
android:background="@drawable/getbg"
android:gravity="center"
android:padding="@dimen/two_dp"
android:text="+1"
android:textColor="@android:color/white"
android:textSize="@dimen/ten_sp" />
</RelativeLayout>
<RelativeLayout
android:layout_
android:layout_
android:layout_weight="1" >
<ImageView
android:id="@+id/imgShare"
android:layout_
android:layout_
android:layout_centerHorizontal="true"
android:layout_centerInParent="true"
android:contentDescription="@string/content_description"
android:src="@drawable/share" />
</RelativeLayout>
</LinearLayout>
<TextView
android:id="@+id/txtId"
android:layout_
android:layout_
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_margin="@dimen/ten_dp"
android:text="id"
android:textSize="20dp" />
</RelativeLayout>
而 Logcat 是,
11-24 18:54:20.354: E/AndroidRuntime(7120): java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.widget.TextView
11-24 18:54:20.354: E/AndroidRuntime(7120): Adapter.onClick(Fragment.java:342)
11-24 18:54:20.354: E/AndroidRuntime(7120): at android.view.View.performClick(View.java:4562)
11-24 18:54:20.354: E/AndroidRuntime(7120): at android.view.View$PerformClick.run(View.java:18918)
11-24 18:54:20.354: E/AndroidRuntime(7120): at android.os.Handler.handleCallback(Handler.java:808)
11-24 18:54:20.354: E/AndroidRuntime(7120): at android.os.Handler.dispatchMessage(Handler.java:103)
11-24 18:54:20.354: E/AndroidRuntime(7120): at android.os.Looper.loop(Looper.java:193)
11-24 18:54:20.354: E/AndroidRuntime(7120): at android.app.ActivityThread.main(ActivityThread.java:5388)
11-24 18:54:20.354: E/AndroidRuntime(7120): at java.lang.reflect.Method.invokeNative(Native Method)
11-24 18:54:20.354: E/AndroidRuntime(7120): at java.lang.reflect.Method.invoke(Method.java:515)
11-24 18:54:20.354: E/AndroidRuntime(7120): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
11-24 18:54:20.354: E/AndroidRuntime(7120): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:655)
11-24 18:54:20.354: E/AndroidRuntime(7120): at dalvik.system.NativeStart.main(Native Method)
【问题讨论】:
android.widget.RelativeLayout 无法转换为 android.widget.TextView.... 移除 onclicklistener 的实现,并为每个可以工作的视图编写单独的视图监听器。我自己检查了示例代码... @Pratt TextView strId = (TextView) (((TextView) view.getParent()).findViewById(R.id.txtId)); System.out.println("!!!!!!!!!strId==="+strId.getText().toString()); @Pratt 这一行是放在 imgLike 按钮点击事件中。 @sri 是的,这是使用 TextView 时的错误 strId = (TextView) (((TextView) view.getParent()).findViewById(R.id.txtId)); System.out.println("!!!!!!!!!strId==="+strId.getText().toString()); 【参考方案1】:试试下面的代码:
public class Adapter1 extends BaseAdapter implements OnClickListener
public ArrayList<HashMap<String, String>> arr = null;
Context context = null;
LayoutInflater layoutInflater = null;
HashMap<String, String> getData = new HashMap<String, String>();
String urlLike = null;
TextView strId = null;
public NewsFeedAdapter(Context context,
ArrayList<HashMap<String, String>> arr)
this.context = context;
this.arr= arr;
layoutInflater = LayoutInflater.from(context);
@Override
public int getCount()
return arr.size();
@Override
public Object getItem(int position)
return arr.get(position);
@Override
public long getItemId(int position)
return position;
@Override
public View getView(int position, View convertView, ViewGroup parent)
ViewHolder viewHolder = null;
if (convertView == null)
convertView = layoutInflater.inflate(
R.layout.my_list_item, null);
/** initialize ViewHolder */
viewHolder = new ViewHolder();
/** Initialize Widgets */
/** Imageview */
viewHolder.imgLike = (ImageView) convertView
.findViewById(R.id.imgLike);
viewHolder.imgComments = (ImageView) convertView
.findViewById(R.id.imgComments);
viewHolder.imgComments.setOnClickListener(this);
viewHolder.imgShare = (ImageView) convertView
.findViewById(R.id.imgShare);
viewHolder.imgShare.setOnClickListener(this);
/** TextView */
viewHolder.txtId = (TextView) convertView
.findViewById(R.id.txtId);
viewHolder.txtDescription = (TextView) convertView
.findViewById(R.id.txtDescription);
getData = arr.get(position);
viewHolder.txtId.setText(getData
.get(Fragment1.TAG_ID));
viewHolder.txtDescription.setText(getData
.get(Fragment1.TAG_MESSAGE));
convertView.setTag(viewHolder);
else
viewHolder = (ViewHolder) convertView.getTag();
convertView.setOnClickListener(new OnClickListener()
@Override
public void onClick(View v)
);
viewHolder.imgLike.setOnClickListener(new OnClickListener()
@Override
public void onClick(View v)
strId=arr.get(position).getId();//or whatever you want to do do here.
);
return convertView;
/** ViewHolder Class */
public class ViewHolder
ImageView imgLike = null, imgComments = null,
imgShare = null;
TextView txtId = null,txtDescription = null;
【讨论】:
不获取 getId();在 strId=arr.get(position).getId(); @Reena 我的办公时间结束了,你可以发邮件给我源,让我解决并回复你。 @Reena 没关系,欢迎您,如果上面的代码工作正常,那么请接受并投票,祝您编码愉快!!!【参考方案2】:试试这个:
strId = (TextView) view.getParent().findViewById(R.id.txtId);
这将解决您的崩溃问题,但您需要重新考虑您的设计。
【讨论】:
【参考方案3】:你需要做的是在 diff 视图上设置 Diff onclick 监听器
viewHolder.txtDescription.setTag(R.id.txtDescription,position);
viewHolder.txtDescription.setOnClickListener(new OnClickListener()
@Override
public void onClick(View v)
int position_clicked=(Integer)v.getTag();
);
对您想要设置监听器的每个视图重复此操作
【讨论】:
我正在使用 int position_clicked=(Integer)v.getTag(); 但它给出了空指针异常。 setTag(R.id.txtDescription,position) 对每个视图使用这个,使用 R.id.txtDescription(即每个视图的 id 作为键) 请帮帮我。我使用 viewHolder.imgMyNewsFeedLike.setTag(R.id.imgMyNewsFeedLike,position); viewHolder.imgMyNewsFeedLike.setOnClickListener(new OnClickListener() @Override public void onClick(View v) int position_clicked=(Integer)v.getTag(); System.out.println("!!!!!!!!!! !id====="+position_clicked); );它给出空指针异常。我在 View getView() 方法中使用这个。【参考方案4】:需要在getView()中初始化strId
在下面的代码中,它无法根据“视图”对象对其进行初始化,因此你得到了空指针。
case R.id.imgLike:
strId = ((TextView) view.findViewById(R.id.txtId));
如果您觉得答案有用,请标记为已解决。
【讨论】:
【参考方案5】:您也可以在适配器类中使用 onClickListener。
看看这个示例代码
viewHolder.imgLike = (ImageView) convertView.findViewById(R.id.imgLike);
viewHolder.imgLike.setOnClickListener(new OnClickListener()
@Override
public void onClick(View arg0)
// TODO Auto-generated method stub
String id = getData.get(Fragment1.TAG_ID);
);
【讨论】:
我是这个但它再次得到 NullPointerException【参考方案6】:试试这样,
@Override
public View getView(int position, View convertView, ViewGroup parent)
ViewHolder viewHolder = null;
if (convertView == null)
convertView = layoutInflater.inflate(
R.layout.my_list_item, null);
/** initialize ViewHolder */
viewHolder = new ViewHolder();
/** Initialize Widgets */
/** Imageview */
viewHolder.imgLike = (ImageView) convertView
.findViewById(R.id.imgLike);
viewHolder.imgLike.setOnClickListener(this);
viewHolder.imgLike.setTag(position);
viewHolder.imgComments = (ImageView) convertView
.findViewById(R.id.imgComments);
viewHolder.imgComments.setOnClickListener(this);
viewHolder.imgShare = (ImageView) convertView
.findViewById(R.id.imgShare);
viewHolder.imgShare.setOnClickListener(this);
/** TextView */
viewHolder.txtId = (TextView) convertView
.findViewById(R.id.txtId);
viewHolder.txtDescription = (TextView) convertView
.findViewById(R.id.txtDescription);
getData = arr.get(position);
viewHolder.txtId.setText(getData
.get(Fragment1.TAG_ID));
viewHolder.txtDescription.setText(getData
.get(Fragment1.TAG_MESSAGE));
convertView.setTag(viewHolder);
else
viewHolder = (ViewHolder) convertView.getTag();
convertView.setOnClickListener(new OnClickListener()
@Override
public void onClick(View v)
);
return convertView;
@Override
public void onClick(View view)
switch (view.getId())
case R.id.imgLike:
View view = listview.getAdapter().getView(((ImageView)v).getTag(), null, listview);
txtId = (TextView) view.findViewById(R.id.txtId);
System.out.println("On Click====="
+ strId.getText().toString());
urlLike = "http://www.example.com?id="
+ strId.getText().toString() + "&user_id="
+ myDetail.getUserId();
new sendLikeData().execute();
break;
case R.id.imgComments:
break;
case R.id.imgShare:
break;
default:
break;
【讨论】:
@Pratt,我正在使用 strId = ((TextView)v);然后给出 java.lang.ClassCastException 之类的错误:android.widget.ImageView cannot be cast to android.widget.TextView @Akash 在适配器类中声明列表视图在哪里? 把你的适配器放在你的列表类中,从那里你可以得到列表视图 视图视图 = listview.getAdapter().getView(((ImageView)v).getTag(), null, listview);在此如何获取listview? 只需将您的适配器代码放在您声明 ListView 的主类中以上是关于如何在android中获取特定列表视图项目的ID?的主要内容,如果未能解决你的问题,请参考以下文章
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