[bugfix] panic when bluetooth.plist parse error

Signed-off-by: shadowhao <shadowhao.tencent.com>

entry.go

@@ -49,7 +49,9 @@ func show() {
 				{"DeviceCache", device.Addr, "BatteryPercentRight"},
 			}
 			batteries := pp.GetAttrByNames(attrs)
-			battery = fmt.Sprintf("C:%v%%/L:%v%%/R:%v%%", batteries[0], batteries[1], batteries[2])
+			if len(batteries) == len(attrs[0])  {
+				battery = fmt.Sprintf("C:%v%%/L:%v%%/R:%v%%", batteries[0], batteries[1], batteries[2])
+			}
 		}
 
 		var subInfo, nextOP string

plist/plist.go

@@ -30,11 +30,19 @@ func (i *Info) GetAttrByNames(attrKeys [][]string) []interface{} {
 	var attr interface{}
 	var mapattr map[string]interface{}
 	var res []interface{}
+	var ok bool
 
 	for _, condition := range attrKeys {
 		attr = i.PlistData
 		for _, c := range condition {
-			mapattr = attr.(map[string]interface{})
+			// https://github.com/haoguanguan/bluetooth_flow/issues/2
+			if attr == nil {
+				break
+			}
+			mapattr, ok = attr.(map[string]interface{})
+			if !ok {
+				break
+			}
 			attr = mapattr[c]
 		}
 		res = append(res, attr)