android 系统属性

今天才发现 android 系统属性还是有一些讲究的

在java层 增加系统

33     public void setString(String key, String val) {
36         SystemProperties.set(key, val);
37     }

这样是无法写系统属性的， 应该这么写

    public void setString(String key, String val) {
	 key += "persist.sys.";
         SystemProperties.set(key, val);
     }

即需要 key的值 需要加上"persist.sys."； 这样才能存储上， 并且下次开机还在，否则下次开就不再了。

另外 key的长读不能超过31.

输入getprop 结果如下

[IPTV_DEV_ID]: [TCL-CN-MT55-F3600A-3DGG]
[dalvik.vm.heapsize]: [128m]
[dalvik.vm.jniopts]: [warnonly]
[dalvik.vm.stack-trace-file]: [/data/anr/traces.txt]
[dev.bootcomplete]: [1]
[dhcp.eth0.dns1]: [10.120.136.71]
[dhcp.eth0.dns2]: [61.134.1.4]
[dhcp.eth0.dns3]: [218.30.19.40]
[dhcp.eth0.dns4]: []
[dhcp.eth0.gateway]: [10.120.139.1]
[dhcp.eth0.ipaddress]: [10.120.139.132]
[dhcp.eth0.leasetime]: [691200]
[dhcp.eth0.mask]: [255.255.255.0]
[dhcp.eth0.pid]: [1332]
[dhcp.eth0.reason]: [BOUND]
[dhcp.eth0.result]: [ok]
[dhcp.eth0.server]: [10.120.136.71]
[hwui.render_dirty_regions]: [false]
[init.svc.MonitorServer]: [running]
[init.svc.adbd]: [running]
[init.svc.bluetoothd]: [stopped]
[init.svc.bootanim]: [stopped]
[init.svc.chompjimei_tv]: [running]
[init.svc.console]: [running]
[init.svc.dbus]: [running]
[init.svc.debuggerd]: [running]
[init.svc.dhcpcd_eth0]: [running]
[init.svc.drm]: [running]
[init.svc.dtv-svc]: [stopped]
[init.svc.insmod]: [stopped]
[init.svc.installd]: [running]
[init.svc.keystore]: [running]
[init.svc.media]: [running]
[init.svc.netd]: [running]
[init.svc.post-init]: [stopped]
[init.svc.pre-init]: [stopped]
[init.svc.ril-daemon]: [running]
[init.svc.servicemanager]: [running]
[init.svc.uploadservice]: [running]
[init.svc.vold]: [running]
[init.svc.zygote]: [running]
[keyguard.no_require_sim]: [true]
[mtk.browser.alwaysFullscreen]: [1]
[mtk.browser.openLinkInSameTab]: [1]
[mtk.browser.supportAutoplay]: [1]
[mtk.browser.useCmpbPlayer]: [1]
[mtk.failed_reboot]: [0]
[net.bt.name]: [Android]
[net.change]: [net.ntp.update]
[net.dns1]: [10.120.136.71]
[net.dns2]: [61.134.1.4]
[net.dns3]: [218.30.19.40]
[net.dnschange]: [1]
[net.eth0.dns1]: [49.0.0.0]
[net.eth0.dns2]: [54.0.0.0]
[net.hostname]: [android-f191aa3f8e3c73be]
[net.ntp.update]: [ok]
[net.qtaguid_enabled]: [1]
[net.tcp.buffersize.default]: [4096,87380,110208,4096,16384,110208]
[net.tcp.buffersize.edge]: [4093,26280,35040,4096,16384,35040]
[net.tcp.buffersize.gprs]: [4092,8760,11680,4096,8760,11680]
[net.tcp.buffersize.hspa]: [4094,87380,262144,4096,16384,262144]
[net.tcp.buffersize.lte]: [524288,1048576,2097152,262144,524288,1048576]
[net.tcp.buffersize.umts]: [4094,87380,110208,4096,16384,110208]
[net.tcp.buffersize.wifi]: [524288,1048576,2097152,262144,524288,1048576]
[persist.sys.3Dstatus]: [1]
[persist.sys.IPTV_DEV_ID]: [TCL-CN-MT55-F3600A-3DG]
[persist.sys.PRJID]: [26]
[persist.sys.SN]: []
[persist.sys.UUID]: []
[persist.sys.bootfromui]: [true]
[persist.sys.country]: [CN]
[persist.sys.getWechatConfigure]: [0]
[persist.sys.language]: [zh]
[persist.sys.localevar]: []
[persist.sys.profiler_ms]: [0]
[persist.sys.strictmode.disable]: [1]
[persist.sys.strictmode.visual]: [0]
[persist.sys.three_D_status]: [1]
[persist.sys.timezone]: [Asia/Shanghai]
[persist.sys.usb.config]: [adb]
[ro.IPTV_DEV_ID]: [TCL-CN-MT55-F3600A-3DG]
[ro.adb.qemud]: [1]
[ro.allow.mock.location]: [1]
[ro.baseband]: [unknown]
[ro.board.platform]: [mt5880]
[ro.bootloader]: [unknown]
[ro.bootmode]: [unknown]
[ro.build.characteristics]: [default]
[ro.build.date.utc]: [1427358622]
[ro.build.date]: [2015��年 03��月 26��日 ��星��期�16:30:22 CST]
[ro.build.description]: [generic_mt5880-eng 4.0.4 IMM76L eng.lw.20150326.162805 test-keys]
[ro.build.display.id]: [generic_mt5880-eng 4.0.4 IMM76L eng.lw.20150326.162805 test-keys]
[ro.build.fingerprint]: [Android/generic_mt5880/mt5880:4.0.4/IMM76L/eng.lw.20150326.162805:eng/test-keys]
[ro.build.host]: [pub]
[ro.build.id]: [IMM76L]
[ro.build.product]: [mt5880]
[ro.build.tags]: [test-keys]
[ro.build.type]: [eng]
[ro.build.user]: [lw]
[ro.build.version.codename]: [REL]
[ro.build.version.incremental]: [eng.lw.20150326.162805]
[ro.build.version.release]: [4.0.4]
[ro.build.version.sdk]: [15]
[ro.carrier]: [unknown]
[ro.com.android.dataroaming]: [true]
[ro.com.android.dateformat]: [MM-dd-yyyy]
[ro.config.alarm_alert]: [Alarm_Classic.ogg]
[ro.config.notification_sound]: [pixiedust.ogg]
[ro.config.ringtone]: [Ring_Synth_04.ogg]
[ro.crypto.fs_flags]: [0x00000006]
[ro.crypto.fs_mnt_point]: [/data]
[ro.crypto.fs_options]: [noauto_da_alloc,errors=continue]
[ro.crypto.fs_real_blkdev]: [/dev/block/mmcblk0p7]
[ro.crypto.fs_type]: [ext4]
[ro.crypto.state]: [unencrypted]
[ro.debuggable]: [1]
[ro.factorytest]: [0]
[ro.hardware.version_id]: [MT5502]
[ro.hardware]: [mt5880]
[ro.kernel.android.checkjni]: [1]
[ro.mtk.browser.cachePolicy]: [1]
[ro.opengles.version]: [131072]
[ro.pm.warmboot]: [0]
[ro.product.board]: [mt5880]
[ro.product.brand]: [Android]
[ro.product.cpu.abi2]: [armeabi]
[ro.product.cpu.abi]: [armeabi-v7a]
[ro.product.device]: [mt5880]
[ro.product.locale.language]: [ldpi]
[ro.product.locale.region]: [CN]
[ro.product.manufacturer]: [MTK]
[ro.product.model]: [Generic Android on mt5880]
[ro.product.name]: [generic_mt5880]
[ro.revision]: [0]
[ro.ril.gprsclass]: [10]
[ro.ril.hsxpa]: [1]
[ro.runtime.firstboot]: [1427694629416]
[ro.secure]: [0]
[ro.serialno]: []
[ro.setupwizard.mode]: [OPTIONAL]
[ro.sf.lcd_density]: [240]
[ro.software.version_id]: [V8-0MT5502-LF1V316]
[ro.wifi.channels]: []
[sys.boot_completed]: [1]
[sys.usb.config]: [adb]
[sys.usb.state]: [adb]
[system_init.startsurfaceflinger]: [1]
[wifi.interface]: [wlan0]

看到了吗？ 出了persist.sys. 还有ro开头的，代表只读的， setprop是无法修改的。还有其他开头的，以后遇到了再研究吧