在Android中试图获得信号强度时强制关闭

添加权限

android.permission.ACCESS\u WIFI\u STATE

---

到您的AndroidManifest.xml文档

发布您的stacktrace。你还能指望别人猜到你的设备上发生了什么吗？

用户10112和当前进程都没有android.permission.ACCESS\u WIFI\u状态。

似乎不言自明。

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        WifiManager mainWifiObj;
        mainWifiObj = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        class WifiScanReceiver extends BroadcastReceiver {
               public void onReceive(Context c, Intent intent) {
               }
            }
            WifiScanReceiver wifiReciever = new WifiScanReceiver();
            registerReceiver(wifiReciever, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
        List<ScanResult> wifiScanList = mainWifiObj.getScanResults(); //error in this line
            String data = wifiScanList.get(0).toString();

FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.wifisignalstrength/com.example.wifisignalstrength.MainActivity}: java.lang.SecurityException: WifiService: Neither user 10112 nor current process has android.permission.ACCESS_WIFI_STATE.
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1967)
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992)
android.app.ActivityThread.access$600(ActivityThread.java:127)
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158)
android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:137)
 E/AndroidRuntime(24463):   at android.app.ActivityThread.main(ActivityThread.java:4511)
java.lang.reflect.Method.invokeNative(Native Method)
java.lang.reflect.Method.invoke(Method.java:511)
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:976)
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:743)
    at dalvik.system.NativeStart.main(Native Method)
 E/AndroidRuntime(24463): Caused by: java.lang.SecurityException: WifiService: Neither user 10112 nor current process has android.permission.ACCESS_WIFI_STATE.
 E/AndroidRuntime(24463):   at android.os.Parcel.readException(Parcel.java:1327)
android.os.Parcel.readException(Parcel.java:1281)
android.net.wifi.IWifiManager$Stub$Proxy.getScanResults(IWifiManager.java:688)
android.net.wifi.WifiManager.getScanResults(WifiManager.java:804)
com.example.wifisignalstrength.MainActivity.onCreate(MainActivity.java:47)
android.app.Activity.performCreate(Activity.java:4486)
android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1052)
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1931)
... 11 more