EditText在ListView中滚动时丢失内容吗? [英] EditText loses content on scroll in ListView?
本文介绍了EditText在ListView中滚动时丢失内容吗?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有一个带有EditText的列表项，我不知道会有多少个项.在EditText中输入一些文本然后向下滚动ListView时出现问题，再次向上滚动后，第一个EditText中没有文本，或者其他ListView.
我已经尝试过TextWatcher，并将数据保存到数组中，但是问题是ListView中返回的视图位置并不总是正确的，所以我从数组中丢失了一些数据.
这是我的代码:
public class EfficientAdapter extends BaseAdapter {
private LayoutInflater mInflater;
public String[] Current;
ArrayList<String> MeterName, PreviousReading, Current_Reading;
JSONArray getArray_Meter_Reading;
public EfficientAdapter(Context context, JSONArray getArray_Meter_Reading) {
mInflater = LayoutInflater.from(context);
this.getArray_Meter_Reading = getArray_Meter_Reading;
MeterName = new ArrayList<String>();
PreviousReading = new ArrayList<String>();
for (int i = 0; i < getArray_Meter_Reading.length(); i++) {
try {
String Meter_Name = getArray_Meter_Reading.getJSONObject(i)
.getString("MeterName").toString();
String previous_Meter_Reading = getArray_Meter_Reading
.getJSONObject(i).getString("PrevMeterReading")
.toString();
MeterName.add(Meter_Name);
PreviousReading.add(previous_Meter_Reading);
// Meter[i]=MeterName.get(i);
// Previous[i]=PreviousReading.get(i);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public int getCount() {
return getArray_Meter_Reading.length();
}
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
final ViewHolder holder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.meter_reading_list, null);
holder = new ViewHolder();
holder.adp_MeterName = (TextView) convertView
.findViewById(R.id.txt_Meter_Name);
holder.adp_Previous = (TextView) convertView
.findViewById(R.id.txt_Previous);
holder.adp_Current = (EditText) convertView
.findViewById(R.id.ed_Current);
holder.adp_Current.addTextChangedListener(new TextWatcher() {
public void onTextChanged(CharSequence s, int start,
int before, int count) {
}
public void beforeTextChanged(CharSequence s, int start,
int count, int after) {
// TODO Auto-generated method stub
}
public void afterTextChanged(Editable s) {
Current[holder.ref] = s.toString();
}
});
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.ref = position;
holder.adp_MeterName.setText(MeterName.get(position));
holder.adp_Previous.setText(PreviousReading.get(position));
// holder.adp_Current.setHint(MeterName.get(position));
// holder.adp_Current.setText(PreviousReading.get(position));
return convertView;
}
class ViewHolder {
TextView adp_MeterName, adp_Previous;
EditText adp_Current;
int ref;
}
}
解决方案
尝试一下:
public class EfficientAdapter extends BaseAdapter {
private LayoutInflater mInflater;
public String[] Current;
ArrayList<String> MeterName, PreviousReading, Current_Reading;
JSONArray getArray_Meter_Reading;
public static HashMap<Integer,String> myList=new HashMap<Integer,String>();
public EfficientAdapter(Context context, JSONArray getArray_Meter_Reading) {
mInflater = LayoutInflater.from(context);
this.getArray_Meter_Reading = getArray_Meter_Reading;
MeterName = new ArrayList<String>();
PreviousReading = new ArrayList<String>();
for (int i = 0; i < getArray_Meter_Reading.length(); i++) {
try {
String Meter_Name = getArray_Meter_Reading.getJSONObject(i)
.getString("MeterName").toString();
String previous_Meter_Reading = getArray_Meter_Reading
.getJSONObject(i).getString("PrevMeterReading")
.toString();
MeterName.add(Meter_Name);
PreviousReading.add(previous_Meter_Reading);
// Meter[i]=MeterName.get(i);
// Previous[i]=PreviousReading.get(i);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// initialize myList
for(int i=0;i<JSON_ARRAY_LENGTH;i++)
{
myList.put(i,"");
}
}
public int getCount() {
return getArray_Meter_Reading.length();
}
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
final ViewHolder holder;
final int pos=position;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.meter_reading_list, null);
holder = new ViewHolder();
holder.adp_MeterName = (TextView) convertView
.findViewById(R.id.txt_Meter_Name);
holder.adp_Previous = (TextView) convertView
.findViewById(R.id.txt_Previous);
holder.adp_Current = (EditText) convertView
.findViewById(R.id.ed_Current);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.adp_Current.addTextChangedListener(new TextWatcher() {
public void onTextChanged(CharSequence s, int start,
int before, int count) {
}
public void beforeTextChanged(CharSequence s, int start,
int count, int after) {
// TODO Auto-generated method stub
}
public void afterTextChanged(Editable s) {
Current[holder.ref] = s.toString();
myList.put(pos,s.toString.trim());
}
});
holder.ref = position;
holder.adp_MeterName.setText(MeterName.get(position));
holder.adp_Previous.setText(PreviousReading.get(position));
// holder.adp_Current.setHint(MeterName.get(position));
// holder.adp_Current.setText(PreviousReading.get(position));
holder.adp_Current.setText(myList.get(position));
return convertView;
}
class ViewHolder {
TextView adp_MeterName, adp_Previous;
EditText adp_Current;
int ref;
}
}
这里我包含了一个HashMap对象，该对象将监视EditText是否包含值.当滚动列表视图时，将通过调用其getView方法以及与每个edittext相关联的文本来再次呈现它. /p>
在此代码中，当您第一次加载listview时，所有edittext都将不包含任何文本.一旦输入一些文本，它将在myList中被注释.因此，当您再次呈现列表时，您的文本将被阻止. /p>
还有一件事情，您应该在if(convertView == null).. else ..块之外实现textwatcher.这是一个更好的做法！
I have list item with EditText in it, I don't know how many items there will be. I have a problem when I enter some text in EditText, and then scroll down a ListView, after I've scroll up again there is no text in my first EditText, or there is some text from other EditText from ListView.
I've tried TextWatcher, and saving data to array, but problems is that returned position of view in ListView isn't always right, so I lost some data from array.
Here is my code:
public class EfficientAdapter extends BaseAdapter {
private LayoutInflater mInflater;
public String[] Current;
ArrayList<String> MeterName, PreviousReading, Current_Reading;
JSONArray getArray_Meter_Reading;
public EfficientAdapter(Context context, JSONArray getArray_Meter_Reading) {
mInflater = LayoutInflater.from(context);
this.getArray_Meter_Reading = getArray_Meter_Reading;
MeterName = new ArrayList<String>();
PreviousReading = new ArrayList<String>();
for (int i = 0; i < getArray_Meter_Reading.length(); i++) {
try {
String Meter_Name = getArray_Meter_Reading.getJSONObject(i)
.getString("MeterName").toString();
String previous_Meter_Reading = getArray_Meter_Reading
.getJSONObject(i).getString("PrevMeterReading")
.toString();
MeterName.add(Meter_Name);
PreviousReading.add(previous_Meter_Reading);
// Meter[i]=MeterName.get(i);
// Previous[i]=PreviousReading.get(i);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public int getCount() {
return getArray_Meter_Reading.length();
}
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
final ViewHolder holder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.meter_reading_list, null);
holder = new ViewHolder();
holder.adp_MeterName = (TextView) convertView
.findViewById(R.id.txt_Meter_Name);
holder.adp_Previous = (TextView) convertView
.findViewById(R.id.txt_Previous);
holder.adp_Current = (EditText) convertView
.findViewById(R.id.ed_Current);
holder.adp_Current.addTextChangedListener(new TextWatcher() {
public void onTextChanged(CharSequence s, int start,
int before, int count) {
}
public void beforeTextChanged(CharSequence s, int start,
int count, int after) {
// TODO Auto-generated method stub
}
public void afterTextChanged(Editable s) {
Current[holder.ref] = s.toString();
}
});
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.ref = position;
holder.adp_MeterName.setText(MeterName.get(position));
holder.adp_Previous.setText(PreviousReading.get(position));
// holder.adp_Current.setHint(MeterName.get(position));
// holder.adp_Current.setText(PreviousReading.get(position));
return convertView;
}
class ViewHolder {
TextView adp_MeterName, adp_Previous;
EditText adp_Current;
int ref;
}
}
解决方案
try this:
public class EfficientAdapter extends BaseAdapter {
private LayoutInflater mInflater;
public String[] Current;
ArrayList<String> MeterName, PreviousReading, Current_Reading;
JSONArray getArray_Meter_Reading;
public static HashMap<Integer,String> myList=new HashMap<Integer,String>();
public EfficientAdapter(Context context, JSONArray getArray_Meter_Reading) {
mInflater = LayoutInflater.from(context);
this.getArray_Meter_Reading = getArray_Meter_Reading;
MeterName = new ArrayList<String>();
PreviousReading = new ArrayList<String>();
for (int i = 0; i < getArray_Meter_Reading.length(); i++) {
try {
String Meter_Name = getArray_Meter_Reading.getJSONObject(i)
.getString("MeterName").toString();
String previous_Meter_Reading = getArray_Meter_Reading
.getJSONObject(i).getString("PrevMeterReading")
.toString();
MeterName.add(Meter_Name);
PreviousReading.add(previous_Meter_Reading);
// Meter[i]=MeterName.get(i);
// Previous[i]=PreviousReading.get(i);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// initialize myList
for(int i=0;i<JSON_ARRAY_LENGTH;i++)
{
myList.put(i,"");
}
}
public int getCount() {
return getArray_Meter_Reading.length();
}
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
final ViewHolder holder;
final int pos=position;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.meter_reading_list, null);
holder = new ViewHolder();
holder.adp_MeterName = (TextView) convertView
.findViewById(R.id.txt_Meter_Name);
holder.adp_Previous = (TextView) convertView
.findViewById(R.id.txt_Previous);
holder.adp_Current = (EditText) convertView
.findViewById(R.id.ed_Current);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.adp_Current.addTextChangedListener(new TextWatcher() {
public void onTextChanged(CharSequence s, int start,
int before, int count) {
}
public void beforeTextChanged(CharSequence s, int start,
int count, int after) {
// TODO Auto-generated method stub
}
public void afterTextChanged(Editable s) {
Current[holder.ref] = s.toString();
myList.put(pos,s.toString.trim());
}
});
holder.ref = position;
holder.adp_MeterName.setText(MeterName.get(position));
holder.adp_Previous.setText(PreviousReading.get(position));
// holder.adp_Current.setHint(MeterName.get(position));
// holder.adp_Current.setText(PreviousReading.get(position));
holder.adp_Current.setText(myList.get(position));
return convertView;
}
class ViewHolder {
TextView adp_MeterName, adp_Previous;
EditText adp_Current;
int ref;
}
}
Here I have included a HashMap object which will keep an eye on if EditText contains value or not.And when you scroll the listview,it will be rendered again by calling its getView method along with the text associated with each edittext.
In this code,when you firstly load listview,all your edittext will be with no text.once you enter some text,it will be noted in myList.So when you again render the list,your text would be prevented.
One more thing,you should implement textwatcher outside if(convertView==null)..else.. block.That's a better practice!
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