在ListView存储复选框的状态 [英] Storing CheckBox state in a ListView
本文介绍了在ListView存储复选框的状态的处理方法，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
我想实现一张code，我发现存储的复选框是在的ListView <国家/ code>，但它并没有奏效。没有人有任何想法，为什么从我的适配器我的code不工作？
包kevin.erica.box;
进口的java.util.ArrayList;
进口kevin.erica.box.R;
进口android.R.color;
进口android.content.Context;
进口android.view.LayoutInflater;
进口android.view.View;
进口android.view.View.OnClickListener;
进口android.view.ViewGroup;
进口android.widget.ArrayAdapter;
进口android.widget.CheckBox;
进口android.widget.ImageView;
进口android.widget.TextView;
公共类MobileArrayAdapter扩展ArrayAdapter＆LT;字符串＆GT; {
私人最终上下文的背景下;
私人最终的String []值;
私人的ArrayList＆LT;布尔＆GT; itemChecked =新的ArrayList＆LT;布尔＆GT;（）;
公共MobileArrayAdapter（上下文的背景下，的String []值）{
超（背景下，R.layout.list_adapter，价值观）;
this.context =背景;
this.values =值;
的for（int i = 0; I＆LT; this.getCount（）;我++）{
itemChecked.add（我，FALSE）; //初始化所有的物品为FALSE
}
}
@覆盖
公共查看getView（最终诠释的立场，观点covertView，ViewGroup中父）{
LayoutInflater充气=（LayoutInflater）上下文
.getSystemService（Context.LAYOUT_INFLATER_SERVICE）;
查看rowView = inflater.inflate（R.layout.list_adapter，父母，假）;
复选框的TextView =（复选框）rowView.findViewById（R.id.checkBox1）;
textView.setTextColor（0xFFFFFFFF的）;
textView.setText（值[位置]）;
//存储状态的尝试
最终的复选框的CBox =（复选框）rowView.findViewById（R.id.checkBox1）; //你
//复选框
cBox.setOnClickListener（新OnClickListener（）{
公共无效的onClick（视图v）{
复选框CB =（复选框）v.findViewById（R.id.checkBox1）;
如果（cb.isChecked（））{
itemChecked.set（位置，真正的）;
//这里做一些操作
}否则如果（！cb.isChecked（））{
itemChecked.set（位置，假）;
//这里做一些操作
}
}
}）;
cBox.setChecked（itemChecked.get（位置））; //这会选中或取消
//复选框中的ListView
//按其原来
//位置和CheckBox永远
//损失他的状态，当你
//滚动列表项。
返回rowView;
}
}
解决方案
您的问题没有说关于存储数据后，该应用程序已关闭任何东西。要存储检查复选框您可以使用一个数据库或简单的文件。贝娄是存储复选框的状态在一个数据库中的一个例子：
公共类SimplePlay扩展ListActivity {
私有String [] soundnames;
私人助手mHelper =新的助手（这一点，position_status.db，NULL，1）;
私人SQLiteDatabase statusDb;
@覆盖
保护无效的onCreate（包savedInstanceState）{
super.onCreate（savedInstanceState）;
//这是模拟数据
soundnames =新的String [40];
的for（int i = 0; I＆LT; 40;我++）{
soundnames [I] =声音+我;
}
//获得的位置被选中（如果有的话）从名单
// 数据库
statusDb = mHelper.getWritableDatabase（）;
光标statusCursor = statusDb.rawQuery（SELECT * FROM状态，NULL）;
INT [] savedStatus = NULL;
如果（（statusCursor = NULL）及！（statusCursor.moveToFirst（）））{
savedStatus =新INT [statusCursor.getCount（）];
INT I = 0;
做 {
savedStatus [I] = statusCursor.getInt（0）;
我++;
}而（statusCursor.moveToNext（））;
}
//如果光标为null或空，我们只是通过空savedStatus到
//适配器的构造，并让它处理（将所有的复选框
//为未选中）
setListAdapter（新MobileArrayAdapter（这一点，soundnames，savedStatus））;
}
公共类MobileArrayAdapter扩展ArrayAdapter＆LT;字符串＆GT; {
私人最终上下文的背景下;
私人最终的String []值;
私人的ArrayList＆LT;布尔＆GT; itemChecked =新的ArrayList＆LT;布尔＆GT;（）;
公共MobileArrayAdapter（上下文的背景下，的String []值，
INT [] oldStatus）{
超（背景下，R.layout.adapters_simpleplay_row，价值观）;
this.context =背景;
this.values =值;
//通过oldStatus使每一个复选框选中，然后循环（如果
// NOT NULL）
的for（int i = 0; I＆LT; this.getCount（）;我++）{
itemChecked.add（我，FALSE）;
}
如果（oldStatus！= NULL）{
对于（INT J = 0; J＆LT; oldStatus.length; J ++）{
itemChecked.set（oldStatus [J]，真正的）;
}
}
}
@覆盖
公共查看getView（最终诠释的立场，观点convertView，
ViewGroup中父）{
查看rowView = convertView;
如果（rowView == NULL）{
LayoutInflater充气=（LayoutInflater）上下文
.getSystemService（Context.LAYOUT_INFLATER_SERVICE）;
rowView = inflater.inflate（R.layout.adapters_simpleplay_row，
父母，假）;
}
复选框的CBox =（复选框）rowView.findViewById（R.id.checkBox1）;
cBox.setTextColor（0xFFFFFFFF的）;
cBox.setText（值[位置]）;
cBox.setTag（新的整数（位置））;
cBox.setOnCheckedChangeListener（新OnCheckedChangeListener（）{
@覆盖
公共无效onCheckedChanged（CompoundButton buttonView，
布尔器isChecked）{
INT realPosition =（整数）buttonView.getTag（）;
如果（器isChecked）{
itemChecked.set（realPosition，真正的）;
//更新存储新签项目数据库：
ContentValues CV =新ContentValues（）;
cv.put（list_position，realPosition）;
statusDb.insert（状态，空，CV）;
} 其他 {
itemChecked.set（realPosition，假）;
//从数据库中删除这个位置，因为它是
//选中
statusDb.delete（状态，list_position =
+ realPosition，NULL）;
}
}
}）;
cBox.setChecked（itemChecked.get（位置））;
返回rowView;
}
}
//与数据库工作
私有类辅助扩展SQLiteOpenHelper {
公共助手（上下文的背景下，字符串名称，CursorFactory厂，
INT版）{
超（背景下，名称，厂家，版本）;
}
@覆盖
公共无效的onCreate（SQLiteDatabase DB）{
//该list_position将举行从列表中的位置
目前检查//
字符串SQL =CREATE TABLE状态（list_position整数）;
db.execSQL（SQL）;
}
@覆盖
公共无效onUpgrade（SQLiteDatabase分贝，INT oldVersion，诠释静态网页）{
//只是接口
}
}
}
在快速测试中，code工作。这仅仅是一个例子。
I'm trying to implement a piece of code I found to store the state of a CheckBox that is in a ListView but it didn't worked. Does anyone have any idea why my code from my adapter isn't working?
package kevin.erica.box;
import java.util.ArrayList;
import kevin.erica.box.R;
import android.R.color;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.ImageView;
import android.widget.TextView;
public class MobileArrayAdapter extends ArrayAdapter<String> {
private final Context context;
private final String[] values;
private ArrayList<Boolean> itemChecked = new ArrayList<Boolean>();
public MobileArrayAdapter(Context context, String[] values) {
super(context, R.layout.list_adapter, values);
this.context = context;
this.values = values;
for (int i = 0; i < this.getCount(); i++) {
itemChecked.add(i, false); // initializes all items value with false
}
}
@Override
public View getView(final int position, View covertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = inflater.inflate(R.layout.list_adapter, parent, false);
CheckBox textView = (CheckBox) rowView.findViewById(R.id.checkBox1);
textView.setTextColor(0xFFFFFFFF);
textView.setText(values[position]);
//Store state attempt
final CheckBox cBox = (CheckBox) rowView.findViewById(R.id.checkBox1); // your
// CheckBox
cBox.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
CheckBox cb = (CheckBox) v.findViewById(R.id.checkBox1);
if (cb.isChecked()) {
itemChecked.set(position, true);
// do some operations here
} else if (!cb.isChecked()) {
itemChecked.set(position, false);
// do some operations here
}
}
});
cBox.setChecked(itemChecked.get(position)); // this will Check or Uncheck the
// CheckBox in ListView
// according to their original
// position and CheckBox never
// loss his State when you
// Scroll the List Items.
return rowView;
}
}
解决方案
You question didn't say anything about storing the data after the application has closed. To store the checked CheckBoxes you could use a database or a simple file. Bellow is an example of storing the CheckBox state in a database:
public class SimplePlay extends ListActivity {
private String[] soundnames;
private Helper mHelper = new Helper(this, "position_status.db", null, 1);
private SQLiteDatabase statusDb;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// this is to simulate data
soundnames = new String[40];
for (int i = 0; i < 40; i++) {
soundnames[i] = "Sound " + i;
}
// Retrieve the list of position that are checked(if any) from the
// database
statusDb = mHelper.getWritableDatabase();
Cursor statusCursor = statusDb.rawQuery("SELECT * FROM status", null);
int[] savedStatus = null;
if ((statusCursor != null) & (statusCursor.moveToFirst())) {
savedStatus = new int[statusCursor.getCount()];
int i = 0;
do {
savedStatus[i] = statusCursor.getInt(0);
i++;
} while (statusCursor.moveToNext());
}
// if the cursor is null or empty we just pass the null savedStatus to
// the adapter constructor and let it handle(setting all the CheckBoxes
// to unchecked)
setListAdapter(new MobileArrayAdapter(this, soundnames, savedStatus));
}
public class MobileArrayAdapter extends ArrayAdapter<String> {
private final Context context;
private final String[] values;
private ArrayList<Boolean> itemChecked = new ArrayList<Boolean>();
public MobileArrayAdapter(Context context, String[] values,
int[] oldStatus) {
super(context, R.layout.adapters_simpleplay_row, values);
this.context = context;
this.values = values;
// make every CheckBox unchecked and then loop through oldStatus(if
// not null)
for (int i = 0; i < this.getCount(); i++) {
itemChecked.add(i, false);
}
if (oldStatus != null) {
for (int j = 0; j < oldStatus.length; j++) {
itemChecked.set(oldStatus[j], true);
}
}
}
@Override
public View getView(final int position, View convertView,
ViewGroup parent) {
View rowView = convertView;
if (rowView == null) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
rowView = inflater.inflate(R.layout.adapters_simpleplay_row,
parent, false);
}
CheckBox cBox = (CheckBox) rowView.findViewById(R.id.checkBox1);
cBox.setTextColor(0xFFFFFFFF);
cBox.setText(values[position]);
cBox.setTag(new Integer(position));
cBox.setOnCheckedChangeListener(new OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView,
boolean isChecked) {
int realPosition = (Integer) buttonView.getTag();
if (isChecked) {
itemChecked.set(realPosition, true);
// update the database to store the new checked item:
ContentValues cv = new ContentValues();
cv.put("list_position", realPosition);
statusDb.insert("status", null, cv);
} else {
itemChecked.set(realPosition, false);
// delete this position from the database because it was
// unchecked
statusDb.delete("status", "list_position = "
+ realPosition, null);
}
}
});
cBox.setChecked(itemChecked.get(position));
return rowView;
}
}
//for working with the database
private class Helper extends SQLiteOpenHelper {
public Helper(Context context, String name, CursorFactory factory,
int version) {
super(context, name, factory, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
// the list_position will hold the position from the list that are
// currently checked
String sql = "CREATE TABLE status (list_position INTEGER);";
db.execSQL(sql);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Just for interface
}
}
}
After a quick test, the code works. It is just an example.
这篇关于在ListView存储复选框的状态的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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