我在用Listview并设置多个项目，每个项目都有喜欢、分享和评论选项。
实际上我已经获取了 Item Id 并且还setText of TextView，成功了。但无法在特定项目的 Like 按钮单击事件上获取项目 ID。
如何获取每个项目的项目 IDListview on Button单击事件？
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_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="@dimen/five_dp" >
<TextView
android:id="@+id/txtDescription"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
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_width="fill_parent"
android:layout_height="150dp"
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_width="fill_parent"
android:layout_height="wrap_content"
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_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
<ImageView
android:id="@+id/imgLike"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerInParent="true"
android:contentDescription="@string/content_description"
android:src="@drawable/like" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
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_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
<ImageView
android:id="@+id/imgComments"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerInParent="true"
android:contentDescription="@string/content_description"
android:src="@drawable/comments" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
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_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
<ImageView
android:id="@+id/imgShare"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
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_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_margin="@dimen/ten_dp"
android:text="id"
android:textSize="20dp" />
</RelativeLayout>
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)
