使用“共享”首选项保存一个布尔数组 [英] Save an array of booleans using Shared preference
问题描述
我有一个很长的布尔值列表，我想使用共享的首选项将其保存在我的应用程序中，这样我就可以保存许多复选框的状态。我现在已经尝试了几种方法，现在已经厌倦了相同的代码，以至于我什至都愿意寻求帮助。
I have a long list of booleans which i want to save In my app using shared preference, so that i can save the state of a number of checkboxes. i have tried a few approaches now, and am now so sick of the same code, that im even willing to ask for help.
我会发布我的代码，但是在那里太多的绿色文本和多余的信息，我认为这是值得的。
I would post my code, but there is so much greentext and redundant information that i dotn think its worth it. But if it helps.
import java.util.HashMap;
import java.util.Map.Entry;
import android.content.Context;
import android.content.SharedPreferences;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.TextView;
public class ExpListAdapter extends BaseExpandableListAdapter {
private Context context;
// second attempt to hold the values
private SharedPreferences keyValues;
private int totalLength;
private String[] parentList = { "Bedding", "Bedroom Items", "Clothing",
"Bags", "Stationary", "Documents", "Electronics", "Toiletries",
"Kitchen Items" };
// used to retain our checklist values, which for some reason dont stick.
private boolean[] checkState;
// multidimensional array for storing the child Strings
private String[][] childList = {
{ "Single/Double sheets", "Single/Double duvet + Covers",
"Pillows + Pillow cases" },
{ "Alarm Clock", "Posters", "Door Wedge", "Lamp", "Small Bin",
"Hamper Basket" },
{ "Casual Clothes, i.e T shirts, jeans, hoodies",
"Smart clothing for interviews and presentations",
"Warm Clothing (especially for newcastle)",
"'Party Clothes' clothes for going out",
"Underwear and socks", "pyjamas", "Comfortable shoes",
"Sports trainers", "Swimwear" },
{ "Everyday bag/backpack", "Gym bag", "Clear Pencil Case",
"Purse/Wallet", "Watch" },
{ "Pins", "A4 Notebooks", "Pens/Pencils", "Highlighters", "Ruler",
"Rubber", "Selotape", "Hole Puncher", "A4 Binders",
"Calculater", "Calender" },
{ "Passport photos", "Passport",
"Driving License (some form of id)", "Your NI Card",
"Insurance Documents", "NHS Medical Card",
"Insurance documents", "Letter of Acceptance",
"Scholarship/bursury letters",
"Rail Card(if you have one)", "C.V" },
{ "Laptop+Charger", "Mouse", "Phone + Charger", "Ethernet Cables",
"USB memory stick", "Headphones", "Digital Camera",
"MP3 Player" },
{ "Shampoo", "Razors", "Toothbrush and toothpaste",
"Make-up/remover", "HairBrush",
"Condoms or other protection!!!" },
{ "Frying Pan", "Wok", "Tin Opener", "Bottle opener", "Glasses",
"Cheese Grater", "Knives", "Chopping Board", "Scissors",
"Tea Towels", "Tupperware", "Cling Film", "Cutlery",
"Crockery" } };
public ExpListAdapter(Context context) {
this.context = context;
int [] lengths = new int [childList.length];
for (int i=0;i<childList.length;i++){
lengths[i] = childList[i].length;
totalLength=totalLength+ lengths[i];
}
// initialised check
checkState = new boolean[totalLength];
}
public Object getChild(int groupPosition, int childPosition) {
return childPosition;
}
//
public long getChildId(int groupPosition, int childPosition) {
// TODO Auto-generated method stub
return 0;
}
public void loadPrefs(){
//where i want to put code to load during my constructor
}
public static boolean savePrefs(){
//where i want to put code to commit data to storage
}
public View getChildView(int groupPosition, int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
//final int mGroupPosition = groupPosition;
//final int mChildPosition = childPosition;
CheckBox checkbox = new CheckBox(context);
//checkbox.setOnCheckedChangeListener(null);
for (int i=0;i<totalLength;i++){
checkState[i]= checkbox.isChecked();
}
/*if (checkState.containsKey(mGroupPosition)) {
boolean getChecked[] = checkState.get(mGroupPosition);
checkbox.setChecked(getChecked[mChildPosition]);
} else {
boolean getChecked[] = new boolean[getChildrenCount(mGroupPosition)];
checkState.put(mGroupPosition, getChecked);
checkbox.setChecked(false);
}
checkbox.setOnCheckedChangeListener(new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView,
boolean isChecked) {
if (isChecked) {
boolean getChecked[] = checkState.get(mGroupPosition);
getChecked[mChildPosition] = isChecked;
checkState.put(mGroupPosition, getChecked);
} else {
boolean getChecked[] = checkState.get(mGroupPosition);
getChecked[mChildPosition] = isChecked;
checkState.put(mGroupPosition, getChecked);
}
}
});*/
checkbox.setText(childList[groupPosition][childPosition]);
checkbox.setPadding(40, 0, 0, 0);
//
return checkbox;
}
// returns the number of children you are having.
public int getChildrenCount(int groupPosition) {
// TODO Auto-generated method stub
return childList[groupPosition].length;
}
// returns the number of parents you have.
public Object getGroup(int groupPosition) {
return groupPosition;
}
public int getGroupCount() {
// TODO Auto-generated method stub
return parentList.length;
}
public long getGroupId(int groupPosition) {
// TODO Auto-generated method stub
return groupPosition;
}
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
TextView text = new TextView(context);
text.setText(parentList[groupPosition]);
text.setPadding(40, 0, 0, 0);
return text;
}
public boolean hasStableIds() {
// TODO Auto-generated method stub
return false;
}
public boolean isChildSelectable(int groupPosition, int childPosition) {
// TODO Auto-generated method stub
return true;
}
}
推荐答案
为了将布尔值数组保存到内存中，建议您按如下所示从布尔值构建一个字符串：
In order to save an array of booleans to memory, I suggest you build a string from the booleans as follows:
初始化
private boolean[] checkState;
private Editor mEditPrefs;
private SharedPreferences mPreferences;
//initialize checkState array and mEditPrefs and mPreferences
保存数组
String save = "";
for (int n = 0; n < checkState.length; n++) {
if (checkState[n] != null) {
if(checkState[n]) {
save = save + "true" + "|$|SEPARATOR|$|";
} else {
save = save + "false" + "|$|SEPARATOR|$|";
}
}
}
mEditPrefs.putString("memory", save);
mEditPrefs.commit();
获取数组
String mem = mPreferences.getString("memory", "");
mEditPrefs.putString("memory", "");
String[] array = getArray(mem); //see below for the getArray() method
checkState = new boolean[array.length];
for(int n = 0; n < array.length; n++){
if(array[n].equals("true"){
checkState[n] = true;
} else {
checkState[n] = false;
}
}
getArray（）方法
public static String[] getArray(String input) {
return input.split("\\|\\$\\|SEPARATOR\\|\\$\\|");
}
这不是一个明智的解决方案，但是SharedPreferences不支持存储数组，因此存储数组的唯一方法是使长字符串由可辨别的分隔符（在这种情况下| $ | SEPARATOR | $ |）分隔，该分隔符不会与要存储的数据混淆。而且，由于没有办法存储数组，我先将布尔值转换为字符串，然后再存储它们，然后从内存中检索它们，并检测它是 true还是 false，并相应地设置checkState数组。
This isn't an elegent solution, but SharedPreferences doesn't support storing arrays, so the only way to store an array is to make a long string separated by a discernible separator (in this case |$|SEPARATOR|$| ) that won't be confused with the data you are storing. Also, since there's no way to store arrays, I converted the booleans to strings before storing them and then I retrieve them from memory and detect if it is "true" or "false" and set the checkState array accordingly.
希望这会有所帮助。我使用了非常相似的过程
Hope this helped. I use a very similar process for storing an array of URLs and it works perfectly.
或者，您可以使用SQLiteDatabase来存储数组，但是仅存储起来可能会有点麻烦一些布尔值。
Alternatively you could use an SQLiteDatabase to store your array, but that might be a little too much work just to store some booleans.
编辑：最初，我认为 toString（）适用于布尔值，但显然不适用于数组。
Originally I thought that toString() would work on a boolean, but apparently not on an array.
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