system.setting-全局变量数据监听

今天在setting里添加了一个新的变量，想要实现对这个变量的监听。现在记录下方法

首先就是明白一点，我们在system.setting里添加的变量，都会被保存在data/data/com.android.providers.settings/databases/settings/system 里面

INSERT INTO "system" VALUES(,'voice_unlock_screen',NULL);
INSERT INTO "system" VALUES(,'voice_unlock_and_launch1',NULL);
INSERT INTO "system" VALUES(,'voice_unlock_and_launch2',NULL);
INSERT INTO "system" VALUES(,'voice_unlock_and_launch3',NULL);
INSERT INTO "system" VALUES(,'volume_voice_earpiece','');
INSERT INTO "system" VALUES(,'volume_ring_speaker','');
INSERT INTO "system" VALUES(,'com_android_contacts_mtk_unread','');
INSERT INTO "system" VALUES(,'hide_rotation_lock_toggle_for_accessibility','');
INSERT INTO "system" VALUES(,'pointer_location','');
INSERT INTO "system" VALUES(,'nanlog_clock_style','');

所以，如果我们要监听，我们只需要监听它所在的数据库就行了

1.写数据库监听动作

    private ContentObserver mAnalogClockObserver = new ContentObserver(new Handler()) {
        @Override
        public void onChange(boolean selfChange) {
            int value = Settings.System.getInt(
                    mContext.getContentResolver(), Settings.System.NANLOG_CLOCK_STYLE, DEFAULT_ANALOG_CLOCK);
            android.util.Log.e("zhangshuli", "value==="+value);
            updateClockView(value);
        }

    };

2.注册监听的数据库

        mContext.getContentResolver().registerContentObserver(Settings.System.getUriFor(Settings.System.NANLOG_CLOCK_STYLE),
                false, mAnalogClockObserver);

这里最主要的就是获得监听数据库的uri，如果我们打log就可以发现，uri如下

uri===content://settings/system/nanlog_clock_style

从system.setting获得变量数据库的方法就是getUriFor方法，具体实现如下

public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/global");
getUriFor(CONTENT_URI, name);
        public static Uri getUriFor(Uri uri, String name) {
            return Uri.withAppendedPath(uri, name);
        } 

这样我们就可以实现数据库的监听了