我正在使用ArrayAdapter创建一个listView。每个视图包含4个TextView和一个ImageButton。当我点击一行时，它会在表格中显示数据，如果我点击行中的imageButton，它会将用户发送到另一个活动。
我的问题是：当我滚动列表并单击一个imageButton（在开始时不在列表的可见部分）我有一个例外
07-23 11:07:50.150: E/AndroidRuntime(9326): FATAL EXCEPTION: main
07-23 11:07:50.150: E/AndroidRuntime(9326): java.lang.IllegalStateException: Could not execute method of the activity
07-23 11:07:50.150: E/AndroidRuntime(9326): atandroid.view.View$1.onClick(View.java:2700)
07-23 11:07:50.150: E/AndroidRuntime(9326):at ndroid.view.View.performClick(View.java:3127)
07-23 11:07:50.150: E/AndroidRuntime(9326): at android.view.View$PerformClick.run(View.java:12025)
07-23 11:07:50.150: E/AndroidRuntime(9326): at android.os.Handler.handleCallback(Handler.java:587)
07-23 11:07:50.150: E/AndroidRuntime(9326): at android.os.Handler.dispatchMessage(Handler.java:92)
07-23 11:07:50.150: E/AndroidRuntime(9326): at android.os.Looper.loop(Looper.java:132)
07-23 11:07:50.150: E/AndroidRuntime(9326): at android.app.ActivityThread.main(ActivityThread.java:4126)
07-23 11:07:50.150: E/AndroidRuntime(9326): at java.lang.reflect.Method.invokeNative(Native Method)
07-23 11:07:50.150: E/AndroidRuntime(9326): at java.lang.reflect.Method.invoke(Method.java:491)
07-23 11:07:50.150: E/AndroidRuntime(9326): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:844)
07-23 11:07:50.150: E/AndroidRuntime(9326): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
07-23 11:07:50.150: E/AndroidRuntime(9326): at dalvik.system.NativeStart.main(Native Method)
07-23 11:07:50.150: E/AndroidRuntime(9326): Caused by: java.lang.reflect.InvocationTargetException
07-23 11:07:50.150: E/AndroidRuntime(9326): at java.lang.reflect.Method.invokeNative(Native Method)
07-23 11:07:50.150: E/AndroidRuntime(9326): at java.lang.reflect.Method.invoke(Method.java:491)
07-23 11:07:50.150: E/AndroidRuntime(9326): at android.view.View$1.onClick(View.java:2695)
07-23 11:07:50.150: E/AndroidRuntime(9326): ... 11 more
07-23 11:07:50.150: E/AndroidRuntime(9326): Caused by: java.lang.NullPointerException
07-23 11:07:50.150: E/AndroidRuntime(9326): at com.android.androidlistview.MainActivity.MyHandler(MainActivity.java:48)
这是我的代码：
MainActivity：
public class MainActivity extends ListActivity {
private ListView listView;
private String id;
private static final int REQUEST_CODE = 1;
private AccountNameListAdapter adapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ArrayList<Account> accountData = new ArrayList<Account>();
for (int i = 0; i < 50; i++) {
Account account = new Account("n" + i, "test", "0154654654",
"gdfg", "gfdg", "2635454564");
accountData.add(account);
}
adapter = new AccountNameListAdapter(this, R.layout.list_detail,
accountData);
listView = this.getListView();
listView.setAdapter(adapter);
}
public void MyHandler(View v) {
ImageButton cb = (ImageButton) v;
int position = Integer.parseInt(cb.getTag().toString());
View o = listView.getChildAt(position).findViewById(R.id.blocCheck);
TextView t = (TextView) listView.getChildAt(position).findViewById(
R.id.id);
Toast.makeText(getApplicationContext(), t.getText(), Toast.LENGTH_LONG)
.show();
Intent editIntent = new Intent(MainActivity.this, EditActivity.class);
editIntent.putExtra("accountId", t.getText());
startActivityForResult(editIntent, REQUEST_CODE);
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK) {
final Account account = new Account("424242", "RhfghOCK", "0154654654",
"ghfgh", "hgfh", "2635454564");
adapter.add(account);
adapter.notifyDataSetChanged();
}
}
}
第48行对应于：
View o = listView.getChildAt(position).findViewById(R.id.blocCheck);
我的自定义广告：
public class AccountNameListAdapter extends ArrayAdapter<Account> {
private Context context;
private int layoutResourceId;
private ArrayList<Account> data;
private TableLayout table;
private TextView tableName;
private TextView tableId;
public AccountNameListAdapter(Context context, int layoutResourceId, ArrayList<Account> data) {
super(context, layoutResourceId, data);
this.layoutResourceId = layoutResourceId;
this.context = context;
this.data = data;
table = (TableLayout) ((Activity) context).findViewById(R.id.tableLayout);
tableName = (TextView) ((Activity) context).findViewById(R.id.NameText);
tableId = (TextView) ((Activity) context).findViewById(R.id.idText);
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
AccountHolder holder = null;
if(convertView == null)
{
LayoutInflater inflater = ((Activity)context).getLayoutInflater();
convertView = inflater.inflate(layoutResourceId, parent, false);
holder = new AccountHolder();
convertView.setClickable(true);
convertView.setFocusable(true);
convertView.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
new AlertDialog.Builder(context).setTitle("touched").show();
table.setVisibility(0);
tableName.setText("ok name");
tableId.setText("ok "+ data.get(position).getAccountId());
}
});
holder.txtName = (TextView)convertView.findViewById(R.id.nom);
holder.txtId = (TextView)convertView.findViewById(R.id.id);
convertView.setTag(holder);
}
else{
holder = (AccountHolder)convertView.getTag();
}
holder.txtName.setText(data.get(position).getName());
holder.txtId.setText(data.get(position).getAccountId());
ImageButton img = (ImageButton) convertView.findViewById (R.id.check);
img.setTag (position);
});
return convertView;
}
static class AccountHolder
{
TextView txtName;
TextView txtId;
}
}
list_detail.xml：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="fill_parent"
android:layout_height="wrap_content">
<TableLayout android:id="@+id/blocCheck"
android:background="#EEF9F8"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:layout_marginTop="5dp"
android:layout_marginBottom="5dp">
<TableRow android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="4sp"
android:paddingBottom="4sp">
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="20sp"
android:layout_weight="1"
android:gravity="center"
>
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:text="Name : "
android:layout_gravity="left"
android:layout_marginRight="5sp" />
<TextView android:id="@+id/nom"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:layout_gravity="left" />
</LinearLayout>
</TableRow>
<TableRow android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="4sp"
android:baselineAligned="true">
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="20sp"
android:layout_weight="1"
android:gravity="center">
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:text="Id : "
android:layout_gravity="left"
android:layout_marginRight="5sp" />
<TextView android:id="@+id/id"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:layout_gravity="left" />
</LinearLayout>
<ImageButton android:layout_height="wrap_content"
android:id="@+id/check"
android:layout_width="wrap_content"
android:background="@drawable/edit"
android:layout_gravity="right"
android:layout_marginRight="10sp"
android:onClick="MyHandler"/>
</TableRow>
</TableLayout>
答案 0 :(得分：0)
只有当位置对应于屏幕上的可见子项时，方法getChildAt才会为ListView返回有效的View（null静止）。提供给该方法的整数必须位于ListView.getLastVisiblePosition() - ListView.getFirstVisiblePosition()定义的区间内。
尝试从position中减去getFirstVisiblePosition()的值：
View o = listView.getChildAt(position - listView.getFirstVisiblePosition()).findViewById(R.id.blocCheck);
答案 1 :(得分：0)
尝试设置自定义列表Linearlayout ID并基于该点击事件调用....
这是ListAdapter的调用
lv.setAdapter(new Listadapter(getApplicationContext(), R.id.listView1, list));
这是ListAdapter类....
public class Listadapter extends ArrayAdapter<BinForBlog>
{
ArrayList<BinForBlog> mList = new ArrayList<BinForBlog>();
public Listadapter(Context context, int textViewResourceId,ArrayList<BinForBlog> list)
{
super(context, textViewResourceId, list);
this.mList = list;
}
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
View v = convertView;
if(v==null)
{
LayoutInflater li = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v=li.inflate(R.layout.custom_blog, null);
}
TextView Title = (TextView) v.findViewById(R.id.blog_title);
TextView Date = (TextView) v.findViewById(R.id.blog_date);
TextView Desc = (TextView) v.findViewById(R.id.blog_desc);
LinearLayout content = (LinearLayout) v.findViewById(R.id.lnrblog);
final BinForBlog listitem = mList.get(position);
// For Underline
SpannableString text = new SpannableString(listitem.getTitle());
text.setSpan(new UnderlineSpan(), 0, text.length(), 0);
Title.setText(text);
Date.setText(listitem.getDate());
Desc.setText(listitem.getDesc());
content.setOnClickListener(new OnClickListener()
{
public void onClick(View arg0)
{
Intent i = new Intent(getApplicationContext(),show_blog_web.class);
i.putExtra("link1", listitem.getLink());
startActivity(i);
}
});
return v;
}
}