我正在尝试创建在按钮上创建新的ListView项的东西,我发现我有一些bug,但是由于我是这个主题的新手,所以我不知道在哪里。
我尝试重写代码多次,尝试使用notifyDataSetChanged(); -它什么也没做尝试谷歌搜索在这里寻找其他主题...这是我的MainActivity.java:
public Button btn;
private ListView lv;
private CustomeAdapter customeAdapter;
public ArrayList<EditModel> editModelArrayList;
int populateListMaxNum =3;
int listNumber = populateListMaxNum;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lv = (ListView) findViewById(R.id.listView);
btn = (Button) findViewById(R.id.btn);
editModelArrayList = populateList();
customeAdapter = new CustomeAdapter(this,editModelArrayList);
lv.setAdapter(customeAdapter);
/* TODO activate button */
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
addToList();
Toast.makeText(getApplicationContext(), "button", Toast.LENGTH_LONG).show();
}
});
}
private ArrayList<EditModel> populateList(){ //this part works perfectly
ArrayList<EditModel> list = new ArrayList<>();
for(int i = 0; i < populateListMaxNum; i++){
EditModel editModel = new EditModel();
//editModel.setEditTextValue(String.valueOf(i));
list.add(editModel);
}
return list;
}
/*TODO make it work = expand */
private void addToList(){ // this part doesn't work nor it doesn't fail
EditModel editModel = new EditModel();
editModelArrayList.add(editModel);
customeAdapter.notifyDataSetChanged();
}
}
这是我的CustomeAdapter.java类:公共类CustomeAdapter扩展BaseAdapter {
private Context context;
public static ArrayList<EditModel> editModelArrayList;
public CustomeAdapter(Context context, ArrayList<EditModel> editModelArrayList) {
this.context = context;
CustomeAdapter.editModelArrayList = editModelArrayList;
}
@Override
public int getViewTypeCount() {
return getCount();
}
@Override
public int getItemViewType(int position) {
return position;
}
@Override
public int getCount() {
return editModelArrayList.size();
}
@Override
public Object getItem(int position) {
return editModelArrayList.get(position);
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
final ViewHolder holder;
if (convertView == null) {
holder = new ViewHolder();
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.lv_item, null, true);
holder.editText = convertView.findViewById(R.id.editid);
convertView.setTag(holder);
}else {
// the getTag returns the viewHolder object set as a tag to the view
holder = (ViewHolder)convertView.getTag();
}
holder.editText.setText(editModelArrayList.get(position).getEditTextValue());
holder.editText.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
editModelArrayList.get(position).setEditTextValue(holder.editText.getText().toString());
}
@Override
public void afterTextChanged(Editable editable) {
}
});
return convertView;
}
private class ViewHolder {
protected EditText editText;
}
}
我希望创建一个新的列表项(EditText + TextView),但是什么也没有发生(Toast消息除外)(经过一些调整后,应用程序由于arrayindexoutofboundsexception length = 3 index = 3错误而崩溃,但不在此设置下)这是所有必要文件的全部:https://gist.github.com/Atingas/52778a247a78131e5b8cb0239fa30965
lv_item.xml中的主要线性布局具有match_parent高度。尝试将其更改为wrap_content。似乎只有一排占据了整个屏幕。