在我的应用程序中，我创建了Custom ListView.So 作为我的问题，我想在ListView.According的特定行中添加和删除一些视图。但它给了我空指针异常。
连续有一个按钮（比如说添加），我正在将它看到到特定的位置。通过单击它，我正在添加一个带有 textView 和按钮的布局（比如说删除）。成功我可以添加新的布局。
但它不是删除添加的布局（空指针exp。）。
以下是适配器类：
public class TestAdapter extends ArrayAdapter<String> {
Context con;
ArrayList<String> listdata;
public TestAdapter(Context context, int textViewResourceId,ArrayList<String> myitem)
{
super(context, textViewResourceId, myitem);
this.con = context;
this.listdata = myitem;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent)
{
LayoutInflater inflater = (LayoutInflater) con.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
final LinearLayout.LayoutParams linearparams=new LinearLayout.LayoutParams(
android.widget.LinearLayout.LayoutParams.WRAP_CONTENT,android.widget.LinearLayout.LayoutParams.WRAP_CONTENT);
if (convertView == null)
{
convertView = inflater.inflate(R.layout.fieldlist, null);
}
TextView data = (TextView) convertView.findViewById(R.id.VTItemTextView);
Button add=(Button)convertView.findViewById(R.id.add);
final EditText amount=(EditText)convertView.findViewById(R.id.amount);
final LinearLayout llmain=(LinearLayout)convertView.findViewById(R.id.llmain);
if(listdata.get(position).equalsIgnoreCase("lorem"))
{
add.setVisibility(View.VISIBLE);
add.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
final LinearLayout llcontent=new LinearLayout(con);
llcontent.setLayoutParams(linearparams);
final TextView textView=new TextView(con);
textView.setLayoutParams(linearparams);
textView.setText(amount.getText().toString());
textView.setTag(position);
final Button delete=new Button(con);
delete.setLayoutParams(linearparams);
delete.setText("delete");
delete.setTag(position);
llcontent.addView(textView);
llcontent.addView(delete);
llmain.addView(llcontent);
notifyDataSetChanged();
delete.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Integer index = (Integer) v.getTag();
//here is Null Pointer Exception
llcontent.removeViewAt(index.intValue());
Integer index1 = (Integer)textView.getTag();
llcontent.removeViewAt(index1.intValue());
notifyDataSetChanged();
}
});
}
});
}
else
{
add.setVisibility(View.GONE);
amount.setVisibility(View.GONE);
}
data.setText(listdata.get(position));
return convertView;
}
}
日志猫：
FATAL EXCEPTION: main
java.lang.NullPointerException
at android.view.ViewGroup.removeViewInternal(ViewGroup.java:3603)
at android.view.ViewGroup.removeViewAt(ViewGroup.java:3567)
at com.example.testapp.TestAdapter$1$1.onClick(TestAdapter.java:91)
at android.view.View.performClick(View.java:4204)
at android.view.View$PerformClick.run(View.java:17355)
at android.os.Handler.handleCallback(Handler.java:725)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
为了测试，我创建了一个单独的演示，它工作正常但是如果我在另一个应用程序中使用这个逻辑，它就不起作用。为什么会这样……？救救我……！