嘿，我创建了一个列表视图并使用自定义 ArrayListAdapter 并覆盖了 getView() 方法。我有一个保存按钮来保存已选中的列表视图项目中的数据。因为它们包含复选框。现在的问题是，当我使用 getchildCount 方法保存数据来循环每个项目（行，孩子）时，它只会遍历可见项目。如果我使用 getCount() 方法，它会给出 NullPointerexception，因为它没有考虑不可见的项目。我知道我必须使用我的适配器来做这一切，但是怎么做？？？？？？？？？？？？这是我使用适配器适配器的课程--------------
package com.bmi.cal.hitesh;
公共类早餐扩展活动{
@Override
public void finish() {
// TODO Auto-generated method stub
super.finish();
db.close();
}
float cal_needed=0;
public int counter =0,listItemCount=0,flag=1;
TextView tv_cal_count;
CheckBox check;
public ListView list;
ContentValues values = new ContentValues();
SQLiteDatabase db;
List<Employer> data = new ArrayList<Employer>();
Cursor cur,cur2;
String type, title,form,descr,tv_cal_str;
int calories;
private Button done;
private TextView tv_cal_needed;
private String cust;
int temp_diet_id[]= new int[234];
//final String CREATE_TABLE= "CREATE TABLE IF NOT EXISTS Bfast_table (" + "id INTEGER PRIMARY KEY AUTOINCREMENT," + "diet TEXT,calories INTEGER,type INTEGER);";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final String MYPREFS = "mySharedPreferences";
SharedPreferences mySharedPreferences = getSharedPreferences(MYPREFS,0);
list= (ListView)findViewById(R.id.list);
done = (Button)findViewById(R.id.button1);
tv_cal_count = (TextView)findViewById(R.id.tv_cal_count);
tv_cal_needed = (TextView)findViewById(R.id.tv_calories);
check = (CheckBox)findViewById(R.id.checkBox1);
db = openOrCreateDatabase("bmi.db",SQLiteDatabase.CREATE_IF_NECESSARY , null );
db.setVersion(1);
db.setLocale(Locale.getDefault());
cust = mySharedPreferences.getString("txt_cust", null);
db.setLockingEnabled(false);
db.execSQL("CREATE TABLE IF NOT EXISTS cust_diet(" + "cd_id INTEGER PRIMARY KEY AUTOINCREMENT," + "cust_id Integer,diet_id INTEGER,cd_validity DATE);");
try {
cur = db.query("tbl_diet",null,"type=?",new String[] {"Breakfast"}, null,null, null);
cur.moveToFirst();
while(!cur.isAfterLast())
{
title = cur.getString(1);
descr = cur.getString(2);
form = cur.getString(6);
type = cur.getString(5);
calories = cur.getInt(3);
data.add(new Employer(title,"Calories : " + calories,"("+descr+")",form));
cur.moveToNext();
}
list.setAdapter(new EmployerArrayAdapter(this, data));
cur.close();
} catch (Exception u) {
u.printStackTrace();
}
done.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
int flag = 1;
listItemCount = list.getCount();
// TODO Auto-generated method stub
System.out.println(cust+"aaaaaaaaaAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAaaaaaaa"+list.getCount());
cur = db.query("user_bmi",null,"cust_id=?",new String[]{cust}, null,null, null);
System.out.println(cur.getCount()+"aaaaaaaaaaaaaaaa");
cur.moveToFirst();
cal_needed = (Float.parseFloat(cur.getString(9)))*(0.25f);
cur.close();
System.out.println(cust+"bbbbbbb");
tv_cal_needed.setText("you must not exceed "+ cal_needed +" calories");
tv_cal_count.setText("calories of your selected diets are as follows : ");
for(int i=0; i<listItemCount; i++)
{ TextView tv_name= (TextView) ((View)list.getChildAt(i)).findViewById(R.id.textViewName);
TextView tv_calorie= (TextView) ((View)list.getChildAt(i)).findViewById(R.id.textViewAddress);
CheckBox cbox = (CheckBox) ((View)list.getChildAt(i)).findViewById(R.id.checkBox1);
if(cbox.isChecked())
{ tv_cal_str = tv_name.getText().toString();
cur = db.query("tbl_diet",null,"diet_title=?",new String[] {tv_cal_str}, null,null, null);
cur.moveToFirst();
temp_diet_id[counter]= cur.getInt(0);;
counter++;
tv_cal_count.append(tv_calorie.getText()+".");
System.out.println(cust+"cccccccc"+temp_diet_id[counter-1]);
System.out.println("not saved sill"+counter+"11111111111111111111111");
String temp_cal= tv_calorie.getText().toString().substring(11);
System.out.println("eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee11111111111111111111111");
float temp_calorie = Float.parseFloat(temp_cal);
System.out.println("eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee222222222222222222222222");
if(temp_calorie>cal_needed)
{ System.out.println("eeeeeeeeeeeeeeeeeeeeeee3333333333333333333333333");
System.out.println(cust+"dddddddddd");
flag=0;
}
}
cur.close();
}
System.out.println("not saved sill"+counter+"22222222222222222222");
if(counter<=3 && counter>=1)
{
for(int i=0; i<listItemCount; i++)
{
CheckBox cbox = (CheckBox) ((View)list.getChildAt(i)).findViewById(R.id.checkBox1);
if(cbox.isChecked())
cbox.setChecked(false);
}
final int temp_count = counter;
System.out.println("not saved sill"+counter+"3333333333333333333333");
if(flag==1){
AlertDialog.Builder builder = new AlertDialog.Builder(BreakFast.this);
builder.setMessage("Do you want to save your BreakFast?")
.setCancelable(false)
.setPositiveButton("Save", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
System.out.println("not saved sill"+temp_count+"3333333333333333333333");
for(int i=0; i<temp_count; i++)
{
cur2 = db.query("user_bmi",null,"cust_id=? and bmi_active=?",new String[]{cust,"1"}, null,null, null);
cur2.moveToFirst();
System.out.println("not saved sill");
values.put("diet_id",temp_diet_id[i]);
values.put("cd_validity",cur2.getString(5));
values.put("cust_id",cust); System.out.println("saved");
db.insert("cust_diet", null, values);
cur.close();
cur2.close();
}
tv_cal_count.setText("Your BreakFast has been saved");
tv_cal_needed.setText(null);
done.setVisibility(View.INVISIBLE); }
})
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
for(int i=0; i<listItemCount; i++)
{
CheckBox cbox = (CheckBox) ((View)list.getChildAt(i)).findViewById(R.id.checkBox1);
if(cbox.isChecked())
cbox.setChecked(false);
}
dialog.cancel();
tv_cal_count.setText(null);
}
});
AlertDialog alert = builder.create();
alert.show();
}
else
{
AlertDialog.Builder builder = new AlertDialog.Builder(BreakFast.this);
builder.setMessage("please select diet which do not exceed "+cal_needed+" calories!!!")
.setCancelable(false)
.setPositiveButton("OK", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int id)
{
tv_cal_count.setText(null);
for(int i=0; i<listItemCount; i++)
{
CheckBox cbox = (CheckBox) ((View)list.getChildAt(i)).findViewById(R.id.checkBox1);
if(cbox.isChecked())
cbox.setChecked(false);
}
}
});
AlertDialog alert = builder.create();
alert.show();
}
counter=0;
}
else
{
tv_cal_count.setText(null);
Dialog mesg = new Dialog(BreakFast.this);
TextView text = new TextView(BreakFast.this);
if(counter==0)
text.setText("plzz select some items but not more then three!!!");
else
text.setText("can't select more then three");
mesg.setContentView(text);
mesg.show();
counter=0;
for(int i=0; i<listItemCount; i++)
{
CheckBox cbox = (CheckBox) ((View)list.getChildAt(i)).findViewById(R.id.checkBox1);
if(cbox.isChecked())
cbox.setChecked(false);
}
}
}
});
}