我的偏好活动（SharedPreferences）：
/**
* Settings Activities java which is connected to the @(R.xml.settings_main)
*/
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.ListPreference;
import android.preference.Preference;
import android.preference.PreferenceFragment;
import android.preference.PreferenceManager;
import android.support.v7.app.AppCompatActivity;
public class SettingsActivity extends AppCompatActivity implements SharedPreferences.OnSharedPreferenceChangeListener {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.settings_activity);
}
public static class InventoryPreferenceFragment extends PreferenceFragment implements Preference.OnPreferenceChangeListener {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.main);
Preference change_currency = findPreference(getString(R.string.settings_change_currency_key));
bindPreferenceSummaryToValue(change_currency);
Preference change_color = findPreference(getString(R.string.settings_change_color_key));
bindPreferenceSummaryToValue(change_color);
}
private void bindPreferenceSummaryToValue(Preference preference) {
preference.setOnPreferenceChangeListener(this);
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(preference.getContext());
String preferenceString = preferences.getString(preference.getKey(), "");
onPreferenceChange(preference, preferenceString);
}
@Override
public boolean onPreferenceChange(Preference preference, Object value) {
String stringValue = value.toString();
if (preference instanceof ListPreference) {
ListPreference listPreference = (ListPreference) preference;
int prefIndex = listPreference.findIndexOfValue(stringValue);
if (prefIndex >= 0) {
CharSequence[] labels = listPreference.getEntries();
preference.setSummary(labels[prefIndex]);
}
} else {
preference.setSummary(stringValue);
}
return true;
}
}
@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this);
// register preference change listener
sharedPrefs.registerOnSharedPreferenceChangeListener(this);
// and set remembered preferences
String currency = sharedPrefs.getString(
getString(R.string.settings_change_currency_key),
getString(R.string.settings_currency_default));
}
在此活动中，我已成功更改EditText的所需部分（确切地说是“$”字符串的货币），当用户在货币设置字段中输入的那个部分时，当货币的Onshared首选项被更改时这部分效果很好
/**
* Allows user to enter a new product or edit an existing one.
*/
public class EditorActivity extends AppCompatActivity
implements LoaderManager.LoaderCallbacks<Cursor> {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_editor);
SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this);
// and set remembered preferences
currency = sharedPrefs.getString(
getString(R.string.settings_change_currency_key),
getString(R.string.settings_currency_default));
在ProductCursorAdapter中我尝试使用SharedPreferences和其他方法在stringPrice中更改货币失败，但在CursorAdapter中我无法使用getString方法。我必须在用户在设置（货币）中输入的文本中更改stringPrice中的“$”字符串。以下是ProductCursorAdapter的代码：
/**
* {@link ProductCursorAdapter} is an adapter for a list or grid view
* that uses a {@link Cursor} of product data as its data source. This adapter knows
* how to create list items for each row of product data in the {@link Cursor}.
*/
public class ProductCursorAdapter extends CursorAdapter {
public static String stringPrice;
/**
* Constructs a new {@link ProductCursorAdapter}.
*
* @param context The context
* @param c The cursor from which to get the data.
*/
public ProductCursorAdapter(Context context, Cursor c) {
super(context, c, 0 /* flags */);
}
/**
* Makes a new blank list item view. No data is set (or bound) to the views yet.
*
* @param context app context
* @param cursor The cursor from which to get the data. The cursor is already
* moved to the correct position.
* @param parent The parent to which the new view is attached to
* @return the newly created list item view.
*/
@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
return LayoutInflater.from(context).inflate(R.layout.list_item, parent, false);
}
/**
* This method binds the product data (in the current row pointed to by cursor) to the given
* list item layout. For example, the name for the current product can be set on the name
* TextView in the list item layout.
*
* @param view Existing view, returned earlier by newView() method
* @param CONTEXT app context
* @param cursor The cursor from which to get the data. The cursor is already moved to the
* correct row.
*/
@Override
public void bindView(View view, final Context CONTEXT, Cursor cursor) {
// CONTEXT is final so it can be used in onClick method below.
// Find individual views that we want to modify in the list item layout
TextView nameTextView = (TextView) view.findViewById(R.id.name);
TextView priceTextView = (TextView) view.findViewById(R.id.price);
final TextView quantityTextView = (TextView) view.findViewById(R.id.quantity_current);
final TextView soldQuantityTextView = (TextView) view.findViewById(R.id.sold_quantity);
// Find the columns of product attributes that we're interested in
int idColumnIndex = cursor.getColumnIndex(ProductEntry._ID);
// idColumnIndex is to assign a number to each button on each list item in
// Catalog Activity
int nameColumnIndex = cursor.getColumnIndex(ProductEntry.COLUMN_PRODUCT_NAME);
int priceColumnIndex = cursor.getColumnIndex(ProductEntry.COLUMN_PRODUCT_PRICE);
int quantityColumnIndex = cursor.getColumnIndex(ProductEntry.COLUMN_PRODUCT_QUANTITY);
int soldColumnIndex = cursor.getColumnIndex(ProductEntry.COLUMN_PRODUCT_SOLD);
// Read the product attributes from the Cursor for the current product
int id = cursor.getInt(idColumnIndex);
String productName = cursor.getString(nameColumnIndex);
double productPrice = cursor.getDouble(priceColumnIndex);
int productQuantity = cursor.getInt(quantityColumnIndex);
int soldQuantity = cursor.getInt(soldColumnIndex);
// Force two decimal places to show in price
DecimalFormat decFor = new DecimalFormat("#.00");
// Here I have to change "$" for currency from onSharedPreferenceChanged
stringPrice = "$" + " " + String.valueOf(decFor.format(productPrice));
// Update the TextViews with the attributes for the current product
nameTextView.setText(productName);
priceTextView.setText(stringPrice);
quantityTextView.setText(String.valueOf(productQuantity));
soldQuantityTextView.setText(String.valueOf(soldQuantity));
// Need productQuantity & soldQuantity number to be available in onClick method.
final int CURR_QTY = productQuantity;
final int SOLD_QTY = soldQuantity;
final Button listViewSoldButton = (Button) view.findViewById(R.id.buttonViewSoldMinusOne);
//If quantity is more than 0 then change the text of the @(listViewSoldButton) to "Sell item(-1)"
if(productQuantity>0){
listViewSoldButton.setText(R.string.sold);
}
//If quantity is equals 0 then change the text of the @(listViewSoldButton) to "Sold Out"
else if(productQuantity==0) {
listViewSoldButton.setText(R.string.sold_out);
}
listViewSoldButton.setTag(id); // Assign id to each button on list view
listViewSoldButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
int mId = (Integer) view.getTag(); // get id of the button clicked on
// Make sure inventory quantity does not go negative
if (CURR_QTY > 0) {
ContentValues listItemsValues = new ContentValues();
listItemsValues.put(ProductEntry.
COLUMN_PRODUCT_QUANTITY, CURR_QTY - 1); // subtract 1 from inventory
listItemsValues.put(ProductEntry.
COLUMN_PRODUCT_SOLD, SOLD_QTY + 1); // add 1 to sold count
Uri currentProductUri = ContentUris.withAppendedId
(ProductEntry.CONTENT_URI, mId);
CONTEXT.getContentResolver().update
(currentProductUri, listItemsValues, null, null);
quantityTextView.setText(String.valueOf(CURR_QTY - 1)); // display current qty
soldQuantityTextView.setText(String.valueOf(SOLD_QTY + 1)); // display sold qty
//temporary change the pushed button's color to @(COLOR.BLUE) and return to the previous color
new Handler().postDelayed(new Runnable() {
public void run() {listViewSoldButton.setBackgroundColor(Color.parseColor("#44d73a"));}}, 300);
listViewSoldButton.setBackgroundColor(Color.BLUE);
} else {
// If quantity is 0 then show Toast saying no more inventory
// available for sale.
Toast.makeText(CONTEXT, CONTEXT.getString(R.string.editor_no_items),
Toast.LENGTH_SHORT).show();
//temporary change the pushed button's color to @(COLOR.RED) and return to the previous color
new Handler().postDelayed(new Runnable() {
public void run() {listViewSoldButton.setBackgroundColor(Color.parseColor("#44d73a"));}}, 400);
listViewSoldButton.setBackgroundColor(Color.RED);
}
}
});
}
}