Android基础篇SharedPreferences的使用

SharedPreferences是Android平台上一个轻量级的存储类，

主要是保存一些常用的配置比如窗口状态，一般在Activity中重载窗口状态onSaveInstanceState保存一般使用SharedPreferences完成。

它提供了Android平台常规的Long长 整形、Int整形、String字符串型的保存。

SharedPreferences使用实例如下：

    public class PreferencesHelper {
        private Context context = null;//上下文
        private String name = "";//名称
        private SharedPreferences preferences = null;
        
        public PreferencesHelper(Context ctx, String name){
            context = ctx;
            this.name = name;
            preferences = getPerferences();
        }
        
        private SharedPreferences getPerferences(){
            SharedPreferences per = context.getSharedPreferences(name, Context.MODE_PRIVATE);
            return per;
        }
        
        public boolean setString(String key, String val){
            return preferences.edit().putString(key, val).commit();
        }
        
        public String getString(String key, String defaultValue){
            return preferences.getString(key, defaultValue);
        }
        
        public boolean setBoolean(String key, boolean val){
            return preferences.edit().putBoolean(key, val).commit();
        }
        
        public boolean getBoolean(String key, boolean defaultValue){
            return preferences.getBoolean(key, defaultValue);
        }
        
        public boolean setFloat(String key, float val){
            return preferences.edit().putFloat(key, val).commit();
        }
        
        public float getFloat(String key, float defaultValue){
            return preferences.getFloat(key, defaultValue);
        }
        
        public boolean setInt(String key, int val){
            return preferences.edit().putInt(key, val).commit();
        }
        
        public int getInt(String key, int defaultValue){
            return preferences.getInt(key, defaultValue);
        }
        
        public boolean setLong(String key, long val){
            return preferences.edit().putLong(key, val).commit();
        }
        
        public long getLong(String key, long defaultValue){
            return preferences.getLong(key, defaultValue);
            
        }
        
        public Map<String, ?> getAll(){
            return preferences.getAll();
        }
        
        public void clear(){
            Editor editor = preferences.edit();
            Map<String, ?> map = preferences.getAll();
            for (Map.Entry<String, ?> e : map.entrySet()) {
                editor.remove(e.getKey());
                editor.commit();
            }
        }
    　　
    }