Android M 开发中wifi列表显示问题的实践

来源：互联网发布：yum安装的软件在哪里编辑：程序博客网时间：2024/05/22 13:43

公司在开发一个读取wifi列表的应用功能时,遇到了兼容性问题,由于之前一直是在Android4.0到Android 5.0之间开发,遇到Android M(6.0)的时候,还真是有点郁闷。言归正传，在网上查询了好多地方，简书上的一篇文章还是很靠谱的，帮我找到了解决方案,附上地址:http://www.jianshu.com/p/3400ca0deeee。

著作权归作者所有，转载请联系作者获得授权，并标注“简书作者”。

Android 6.0发布近一年之后，我遇到了第一个Android 6.0的兼容性问题，getScanResults在Android6.0上返回了一个空列表，getScanResults的源码是这样的：

public List<ScanResult> getScanResults(String callingPackage) {public List<ScanResult> getScanResults(String callingPackage) { enforceAccessPermission(); int userId = UserHandle.getCallingUserId(); int uid = Binder.getCallingUid(); boolean canReadPeerMacAddresses = checkPeersMacAddress(); boolean isActiveNetworkScorer = NetworkScorerAppManager.isCallerActiveScorer(mContext, uid); boolean hasInteractUsersFull = checkInteractAcrossUsersFull(); long ident = Binder.clearCallingIdentity(); try {//此处重要 if (!canReadPeerMacAddresses && !isActiveNetworkScorer && !isLocationEnabled()) { return new ArrayList<ScanResult>(); } if (!canReadPeerMacAddresses && !isActiveNetworkScorer && !checkCallerCanAccessScanResults(callingPackage, uid)) { return new ArrayList<ScanResult>(); } if (mAppOps.noteOp(AppOpsManager.OP_WIFI_SCAN, uid, callingPackage) != AppOpsManager.MODE_ALLOWED) { return new ArrayList<ScanResult>(); } if (!isCurrentProfile(userId) && !hasInteractUsersFull) { return new ArrayList<ScanResult>(); } return mWifiStateMachine.syncGetScanResultsList(); } finally { Binder.restoreCallingIdentity(ident);} } private boolean isLocationEnabled() { return Settings.Secure.getInt(mContext.getContentResolver(), Settings.Secure.LOCATION_MODE, Settings.Secure.LOCATION_MODE_OFF) != Settings.Secure.LOCATION_MODE_OFF; } enforceAccessPermission(); int userId = UserHandle.getCallingUserId(); int uid = Binder.getCallingUid(); boolean canReadPeerMacAddresses = checkPeersMacAddress(); boolean isActiveNetworkScorer = NetworkScorerAppManager.isCallerActiveScorer(mContext, uid); boolean hasInteractUsersFull = checkInteractAcrossUsersFull(); long ident = Binder.clearCallingIdentity(); try { if (!canReadPeerMacAddresses && !isActiveNetworkScorer && !isLocationEnabled()) { return new ArrayList<ScanResult>(); } if (!canReadPeerMacAddresses && !isActiveNetworkScorer && !checkCallerCanAccessScanResults(callingPackage, uid)) { return new ArrayList<ScanResult>(); } if (mAppOps.noteOp(AppOpsManager.OP_WIFI_SCAN, uid, callingPackage) != AppOpsManager.MODE_ALLOWED) { return new ArrayList<ScanResult>(); } if (!isCurrentProfile(userId) && !hasInteractUsersFull) { return new ArrayList<ScanResult>(); } return mWifiStateMachine.syncGetScanResultsList(); } finally { Binder.restoreCallingIdentity(ident); } } private boolean isLocationEnabled() { return Settings.Secure.getInt(mContext.getContentResolver(), Settings.Secure.LOCATION_MODE, Settings.Secure.LOCATION_MODE_OFF) != Settings.Secure.LOCATION_MODE_OFF; }

//此处重要 if (!canReadPeerMacAddresses && !isActiveNetworkScorer && !isLocationEnabled()) { return new ArrayList<ScanResult>(); }

可以看到如果定位关闭，那么将直接返回一个空的列表，当我去打开定位时，果然就正常的返回了WiFi列表，于是解决方案就是在6.0以上系统中，帮用户打开GPS开关：

if (Build.VERSION.SDK_INT >= 23 && !AppUtil.isGpsOPen(this)) {    Settings.Secure.putInt(getContentResolver(),Settings.Secure.LOCATION_MODE, 1);}

以上这段方法,可能SDK版本的问题吧,我的试验并不成功,不得不改为提示用户去打开GPS开关:

if (Build.VERSION.SDK_INT >= 23 && !isGpsOpen(MainTestActivity.this)) {            Intent gpsIntent = new Intent();            gpsIntent.setClassName("com.Android.settings", "com.android.settings.widget.SettingsAppWidgetProvider");            gpsIntent.addCategory("android.intent.category.ALTERNATIVE");            gpsIntent.setData(Uri.parse("custom:3"));            try {               PendingIntent.getBroadcast(MainTestActivity.this, 0, gpsIntent, 0).send();            } catch (PendingIntent.CanceledException e) {               e.printStackTrace();            }         }

当然，这里还需要用到一些权限：

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/><uses-permission android:name="android.permission.WRITE_SECURE_SETTINGS"/>

如果App不是system app，那么是获取不到WRITE_SECURE_SETTINGS权限的，此时就要引导用户去手动打开GPS开关，跟简书作者心情一样：为何扫描个WiFi也需要打开GPS。

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