如何从Android的列表视图中选择一个特定的项目? [英] How to select a particular item from the listview in android?
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问题描述
我有一个列表视图.它通过使用包含来自Web服务的一些数据.
I have one list-view.It contains some data from the web-service by consuming it.
在这里，我需要的是，如果我从该列表视图中单击任何项目，则它想显示来自Web服务的数据. 我是否可以为此编写任何循环代码? 该怎么做?
Here my need is, if i click any item from that list-view, it wants to show data from the web service. have i to write any loop code for this?if so how?examples please. How to do this?
Logcat
03-20 13:09:07.187: W/KeyCharacterMap(275): No keyboard for id 0
03-20 13:09:07.187: W/KeyCharacterMap(275): Using default keymap: /system/usr/keychars/qwerty.kcm.bin
03-20 13:09:13.116: I/System.out(275): Transparent 17170445
03-20 13:09:13.136: W/System.err(275): org.json.JSONException: Value Login of type java.lang.String cannot be converted to JSONArray
03-20 13:09:13.136: W/System.err(275): at org.json.JSON.typeMismatch(JSON.java:107)
03-20 13:09:13.136: W/System.err(275): at org.json.JSONArray.<init>(JSONArray.java:91)
03-20 13:09:13.136: W/System.err(275): at org.json.JSONArray.<init>(JSONArray.java:103)
03-20 13:09:13.136: W/System.err(275): at com.example.png.StationsListActivity.callService(StationsListActivity.java:115)
03-20 13:09:13.136: W/System.err(275): at com.example.png.StationsListActivity$4.run(StationsListActivity.java:103)
03-20 13:09:13.196: D/AndroidRuntime(275): Shutting down VM
03-20 13:09:13.196: W/dalvikvm(275): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
03-20 13:09:13.206: E/AndroidRuntime(275): FATAL EXCEPTION: main
03-2 0 13:09:13.206: E/AndroidRuntime(275): java.lang.NullPointerException
03-20 13:09:13.206: E/AndroidRuntime(275): at com.example.png.StationsListActivity$1.handleMessage(StationsListActivity.java:43)
03-20 13:09:13.206: E/AndroidRuntime(275): at android.os.Handler.dispatchMessage(Handler.java:99)
03-20 13:09:13.206: E/AndroidRuntime(275): at android.os.Looper.loop(Looper.java:123)
03-20 13:09:13.206: E/AndroidRuntime(275): at android.app.ActivityThread.main(ActivityThread.java:4627)
03-20 13:09:13.206: E/AndroidRuntime(275): at java.lang.reflect.Method.invokeNative(Native Method)
03-20 13:09:13.206: E/AndroidRuntime(275): at java.lang.reflect.Method.invoke(Method.java:521)
03-20 13:09:13.206: E/AndroidRuntime(275): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
03-20 13:09:13.206: E/AndroidRuntime(275): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
03-20 13:09:13.206: E/AndroidRuntime(275): at dalvik.system.NativeStart.main(Native Method)
StationsListActivity.java
public class StationsListActivity extends Activity {
TextView txt;
String res_data;
Button btn_info;
ListView listView;
ProgressDialog progressDialog;
List<Stations> list;
Handler handler =new Handler()
{
public void handleMessage(android.os.Message msg)
{
if(progressDialog.isShowing())
{
progressDialog.cancel();
if(list.size() > 0)
{
listView.setAdapter(new StationAdapter(StationsListActivity.this, android.R.id.text1,list));
}
else
{
Toast.makeText(StationsListActivity.this, "List is Empty",Toast.LENGTH_LONG).show();
}
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.stations_list_layout);
listView = (ListView)findViewById(R.id.listView_stations);
Bundle extras=getIntent().getExtras();
if(extras!=null)
{
res_data =extras.getString("transfered_data");
}
System.out.println("Transparent "+android.R.color.transparent);
listView = (ListView) findViewById(R.id.listView_stations);
btn_info = (Button)findViewById(R.id.btn_info);
progressDialog = new ProgressDialog(StationsListActivity.this);
progressDialog.setTitle("Loading");
progressDialog.setMessage("Please Wait");
btn_info.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intnt = new Intent(StationsListActivity.this , InformationsActivity.class);
startActivity(intnt);
}
});
Thread thread =new Thread()
{
@Override
public void run() {
// TODO Auto-generated method stub
callService();
handler.sendEmptyMessage(0);
}
};
thread.start();
progressDialog.show();
}
public void callService() {
// TODO Auto-generated method stub
try {
JSONArray array = new JSONArray(String.valueOf(res_data).replace("verifyUserResponse{return=", "").replace("; }", ""));
list = new ArrayList<Stations>();
for (int i = 0; i < array.length(); i++)
{
System.out.println(array.getJSONObject(i).get("1")+" == "+array.getJSONObject(i).get("0"));;
Stations stations =new Stations();
stations.station_code = (String) array.getJSONObject(i).get("0");
stations.station_name = (String) array.getJSONObject(i).get("1");
list.add(stations);
stations = null;
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
StationAdaper.java
public class StationAdapter extends ArrayAdapter<Stations> {
Context context;
List<Stations> list;
public StationAdapter(Context context, int textViewResourceId,
List<Stations> objects) {
super(context, textViewResourceId, objects);
this.context = context ;
this.list = objects ;
// TODO Auto-generated constructor stub
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.station_child, null);
TextView name = (TextView) view.findViewById(R.id.textView_single_item);
ImageView img = (ImageView)view.findViewById(R.id.imageView1);
Stations stations =list.get(position);
name.setText(stations.station_name);
return view;
}}
Stations.java 公共类站 {
Stations.java public class Stations {
public String station_name ="";
public String station_code ="";
}
station_child.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal">
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="55dp" >
<TextView
android:id="@+id/textView_single_item"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:inputType="text"
android:textColor="#ffffff"
android:textStyle="normal"
android:textAppearance="?android:attr/textAppearanceMedium" />
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:layout_marginRight="10dp"
android:background="@drawable/arrow"/>
</RelativeLayout></LinearLayout>
建议 感谢您的宝贵时间！..
suggestions please Thanks for your precious time!..
推荐答案
将此代码包含在OnCreate中
Include this code in your OnCreate
// listening to single list item on click
listview.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// selected item
String nameOfStation = ((TextView)view.findViewById(R.id.textView_single_item)).getText().toString();
}
});
LogCat之后更新
您得到的是一个JSONException，它与您的听众无关.请更改
Update after LogCat
What you're getting is a JSONException which has got nothing to do with your listener. Please change
JSONArray array = new JSONArray(String.valueOf(res_data).replace("verifyUserResponse{return=", "").replace("; }", ""));
收件人:
JSONArray array = new JSONArray(res_data);
这将解决异常情况.
这篇关于如何从Android的列表视图中选择一个特定的项目?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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