feat: add adb screencap sub command

hrp/cmd/adb/screencap.go

@@ -0,0 +1,37 @@
+package adb
+
+import (
+	"fmt"
+	"io/ioutil"
+	"time"
+
+	"github.com/spf13/cobra"
+)
+
+var screencapAndroidDevicesCmd = &cobra.Command{
+	Use:   "screencap",
+	Short: "Start android screen capture",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		device, err := getDevice(serial)
+		if err != nil {
+			return err
+		}
+
+		res, err := device.ScreenCap()
+		if err != nil {
+			return err
+		}
+
+		filepath := fmt.Sprintf("screencap_%d.png", time.Now().Unix())
+		if err = ioutil.WriteFile(filepath, res, 0o644); err != nil {
+			return err
+		}
+		fmt.Println("screencap saved to", filepath)
+		return nil
+	},
+}
+
+func init() {
+	screencapAndroidDevicesCmd.Flags().StringVarP(&serial, "serial", "s", "", "filter by device's serial")
+	androidRootCmd.AddCommand(screencapAndroidDevicesCmd)
+}