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需求分析
本文介绍一个SharedPreference的使用的工具类，在Android开发的过程中不可避免的会使用SharedPreference来缓存一个数据，(1)如果频繁使用的话还是最好把存取操作放在子线程去处理；(2)如果不写一个关于SharedPerference的工具类,没法复用很多操作,（3）如果每个对应的业务的数据都写对应的存取删除操作的话，到项目后期会有很多，难以维护；
针对上面的三个问题实现一个比较通用可扩展性强的工具里，SharedPerference支持六种数据：String,Boolean,Int,Long,Float和Set<String>,大部分业务都可以支持，当需要保存Object和List<Object>，均可以通过使用Object->Json->String再进行保存，SharedPerference是保存在xml文件中键值对，所以有两个重要的属性就是fileName和keyName，所以
SharePerferenceUtil的包含两个内部类：FILE_KEYS和VALUE_KEYS作为索引。
public class SPUtil {
public static final class FILE_KEYS{
public static final String APP_STATUS = "app_status";
public static final String USER_INFO = "user_info";
}
public static final class VALUE_KEYS{
public static final String IS_LOGIN = "is_login";
public static final String USER = "user";
public static final String MOBILE_LOGIN_LIST = "mobile_login_list";
}
...
读取成功后的回调接口:
public interface SPResultListener<T> {
void onResult(T t);
}
当存取List数据时需要Id作为唯一标识，所以Object必须实现接口：
public interface ShareCacheableData {
String getId();
}
1、首先基本数据类型，以Boolean为例：
存数据，调用RxJava使得写操作在I/O线程中进行：
public static final synchronized void saveBoolean(final String fileKey, final String valueKey, final boolean value){
Observable.create(new Observable.OnSubscribe<Object>() {
@Override
public void call(Subscriber<? super Object> subscriber) {
SharedPreferences sp = OpenEyeApplication.getInstance().getSharedPreferences(fileKey,Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sp.edit();
editor.putBoolean(valueKey,value);
editor.commit();
}
}).subscribeOn(Schedulers.io()).subscribe();
}
读数据,调用RxJava使得读取操作在I/O线程中进行,读取成功后在UI线程中进行的回调:
public static final void getBoolean(final String fileKey, final String valueKey, final SPResultListener<Boolean> resultListener) {
Observable.fromCallable(new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
SharedPreferences sp = OpenEyeApplication.getInstance().getSharedPreferences(fileKey, Context.MODE_PRIVATE);
return sp.getBoolean(valueKey, false);
}
}).subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<Boolean>() {
@Override
public void call(Boolean value) {
value = (value == null) ? false:value;
if (resultListener != null) {
resultListener.onResult(value);
}
}
});
}
2、存取实体对象，和存取基本的数据多了一个转String的过程，
保存实体对象：
public static final <T extends Serializable> void saveModel(final String fileKey, final String valueKey, final T t){
Observable.create(new Observable.OnSubscribe<Object>() {
@Override
public void call(Subscriber<? super Object> subscriber) {
SharedPreferences sp = OpenEyeApplication.getInstance().getSharedPreferences(fileKey,Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sp.edit();
editor.putString(valueKey,new Gson().toJson(t));
editor.commit();
}
}).subscribeOn(Schedulers.io()).subscribe();
}
读取实体对象：
public static final <T extends Serializable> void getModel(final String fileKey, final String valueKey, final Class<T> clazz, final SPResultListener<T> resultListener) {
Observable.fromCallable(new Callable<T>() {
@Override
public T call() throws Exception {
SharedPreferences sp = OpenEyeApplication.getInstance().getSharedPreferences(fileKey, Context.MODE_PRIVATE);
String sResult = sp.getString(valueKey, "");
if (TextUtils.isEmpty(sResult)) {
return null;
} else {
T t = new Gson().fromJson(sResult, clazz);
return t;
}
}
}).subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<T>() {
@Override
public void call(T value) {
if (resultListener != null) {
resultListener.onResult(value);
}
}
});
}
2、存取实体对象列表，Gson转换的时候容易出错，可以特别注意一下：
往列表保存对象，ShareCacheableData是为了获取对象的唯一标识：
public static final <T extends ShareCacheableData> void putList(final String fileKey, final String valueKey, final Class<T[]> clazz, final T t){
Observable.create(new Observable.OnSubscribe<Object>() {
@Override
public void call(Subscriber<? super Object> subscriber) {
SharedPreferences sp = OpenEyeApplication.getInstance().getSharedPreferences(fileKey,Context.MODE_PRIVATE);
String listJson = sp.getString(valueKey,"");
List<T> oldList = new ArrayList<>();
if (!TextUtils.isEmpty(listJson)){
T[] array = new Gson().fromJson(listJson,clazz);
oldList = new ArrayList<T>(Arrays.asList(array));
}
Iterator<T> iterator = oldList.iterator();
while (iterator.hasNext()){
T item = iterator.next();
if (TextUtils.equals(item.getId(),t.getId())){
iterator.remove();
}
}
oldList.add(t);
SharedPreferences.Editor editor = sp.edit();
editor.putString(valueKey,new Gson().toJson(oldList));
editor.commit();
subscriber.onStart();
}
}).subscribeOn(Schedulers.io()).subscribe();
}
读取对象列表：
public static final <T extends ShareCacheableData> void getList(final String fileKey, final String valueKey, final Class<T[]> clazz, final SPResultListener<List<T>> resultListener) {
Observable.fromCallable(new Callable<List<T>>() {
@Override
public List<T> call() throws Exception {
SharedPreferences sp = OpenEyeApplication.getInstance().getSharedPreferences(fileKey, Context.MODE_PRIVATE);
String sResult = sp.getString(valueKey, "");
if (TextUtils.isEmpty(sResult)) {
return null;
} else {
T[] list = new Gson().fromJson(sResult, clazz);
return new ArrayList<T>(Arrays.asList(list));
}
}
}).subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<List<T>>() {
@Override
public void call(List<T> value) {
if (resultListener != null) {
resultListener.onResult(value);
}
}
});
}
结束了。。。
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