Dji Mobile SDK 基礎實現（二）

本文簡要介紹如何通過調用DJI Mobile SDK，實現獲取和釋放無人機的控制權限、模擬遙控器按鈕控制無人機的飛行、獲取無人機的回傳視頻、獲取無人機參數、實現和onboard SDK的數據透傳。

下面逐個介紹以上內容，余下內容在前面文章已作介紹（文章末尾附上GitHub鏈接）：

• 獲取無人機的回傳視頻
• 獲取無人機參數
• 實現和onboard SDK的數據透傳

獲取無人機的回傳視頻

1、調用並實例化TextureView控件，並在調用類中實現SurfaceTextureListener接口；

2、設置回調接口並初始化回傳視頻：

/**
*設置回調接口
*/
protected DJICodecManager mCodecManager = null;//視頻編碼
private DJIFlightControllerDelegate.FlightControllerReceivedDataFromExternalDeviceCallback mRecvCallback = null;
protected CameraReceivedVideoDataCallback mReceivedVideoDataCallBack = null;
protected DJIOnReceivedVideoCallback mOnReceivedVideoCallback = null;
private DJIBaseProduct mProduct = null;//無人機實例
//設置視頻的回調
        mReceivedVideoDataCallBack = new CameraReceivedVideoDataCallback() {
            @Override
            public void onResult(byte[] videoBuffer, int size) {
                count++;
                if (mCodecManager != null) {
                        mCodecManager.sendDataToDecoder(videoBuffer, size);
                } else {
                    Log.e(TAG, "mCodecManager is null");
                }
            }
        };

/**
*初始化回傳視頻
*/
 private void initVideo() {
        try {
            mProduct = VirtualStickApplication.getProductInstance();
        } catch (Exception exception) {
            mProduct = null;
        }

        if (null == mProduct || !mProduct.isConnected()) {
            mCamera = null;
        } else {
            if (null != mVideoSurface) {
                mVideoSurface.setSurfaceTextureListener(this);
            }

            if (!mProduct.getModel().equals(Model.UnknownAircraft)) {
                mCamera = mProduct.getCamera();
                if (mCamera != null) {
                    mCamera.setDJICameraReceivedVideoDataCallback(mReceivedVideoDataCallBack);
                }
            } else {
                if (null != mProduct.getAirLink()) {
                    if (null != mProduct.getAirLink().getLBAirLink()) {
                        // Set the callback
                        mProduct.getAirLink().getLBAirLink().setDJIOnReceivedVideoCallback(mOnReceivedVideoCallback);
                        mProduct.getAirLink().getLBAirLink().setFPVQualityLatency(DJILBAirLink.LBAirLinkFPVVideoQualityLatency.LowLatency,new DJIBaseComponent.DJICompletionCallback() {
                            @Override
                            public void onResult(DJIError djiError) {
                                if (djiError != null)
                                    VirtualStickApplication.logError("setFPVQualityLatency（）error:", djiError);
                            }
                        });
                    }
                }
            }
        }
    }
 

獲取無人機參數

獲取獲取無人機的剩余電量，以百分比的形式返回

private DJIBaseProduct mProduct = null;//無人機實例
 try {
                mProduct = VirtualStickApplication.getProductInstance();
            } catch (Exception exception) {
                mProduct = null;
            }
            if(mProduct != null && mProduct.isConnected()) {
                //獲取無人機的剩余電量，以百分比的形式返回
                try{
                    mProduct.getBattery().setBatteryStateUpdateCallback(new DJIBattery.DJIBatteryStateUpdateCallback() {
                        @Override
                        public void onResult(DJIBatteryState djiBatteryState) {
                            if(djiBatteryState == null){
                                VirtualStickApplication.logInfo("電量為空");
                            }else{
                                StringBuffer mBuffer = new StringBuffer();
                                mBuffer.append(djiBatteryState.getBatteryEnergyRemainingPercent());
                                tvBattery.setText(mBuffer.toString()+"%");
                                if(djiBatteryState.getBatteryEnergyRemainingPercent() != 0 && djiBatteryState.getBatteryEnergyRemainingPercent() <= 30){
                                      if(entry){
                                          AlertDialog.Builder builder =  new  AlertDialog.Builder(VirtualStickActivity.this);
                                          builder.setTitle("警告" )
                                                  .setMessage("電池電量不足！" )
                                                  .setPositiveButton("確認" ,  null )
                                                  .setNegativeButton("取消" , null)
                                                  .show();
                                          entry = false;
                                      }
                                }else{
                                    entry = true;
                                }
                            }
                        }
                    });
                }catch(Exception e){
                    Toast.makeText(VirtualStickActivity.this,"1"+e.toString(),Toast.LENGTH_LONG).show();
                    e.printStackTrace();
                }
 

獲取飛行器所在所在高度、飛行速度、無人機姿態、GPS信號
1、獲取flightController 對象；

DJIFlightController flightController;
public void setAircraft(DJIBaseProduct djiAircraft){
        if(djiAircraft==null){

            return;
        }
        flightController=((DJIAircraft)djiAircraft).getFlightController();
        if(flightController!=null) {

        }

    }
 

2、通過flightController對象調用方法獲取飛行器所在所在高度、飛行速度、無人機姿態、GPS信號；
所在高度

public String getHeight(){
        if(flightController != null){
            DJIFlightControllerDataType.DJIFlightControllerCurrentState currentState = flightController.getCurrentState();
            if (currentState != null) {
                return currentState.getAircraftLocation().getAltitude() + "";
            }
        }
        return null;
    }

飛行速度

//獲取前後速度
    public String getX(){
        if(flightController != null){
        DJIFlightControllerDataType.DJIFlightControllerCurrentState currentState = flightController.getCurrentState();
            if (currentState != null) {
                currentState.getGpsSignalStatus();
                return currentState.getVelocityX() + "";
            }
        }

        return null;
    }

    //獲取左右速度
    public String getY(){
        if(flightController != null){
            DJIFlightControllerDataType.DJIFlightControllerCurrentState currentState = flightController.getCurrentState();
            if (currentState != null) {
                return currentState.getVelocityY() + "";
            }
        }
        return null;
    }

    //獲取上下速度
    public String getZ(){
        if(flightController != null){
            DJIFlightControllerDataType.DJIFlightControllerCurrentState currentState = flightController.getCurrentState();
            if (currentState != null) {
                return currentState.getVelocityZ() + "";
            }
        }
        return null;
    }

無人機姿態（roll、yaw、pitch）

public String getYaw(){
        if(flightController != null){
            DJIFlightControllerDataType.DJIFlightControllerCurrentState currentState = flightController.getCurrentState();
            if (currentState != null) {
                return "pitch:"+currentState.getAttitude().pitch+"  Yaw:"+currentState.getAttitude().yaw
                        +"  Roll:"+currentState.getAttitude().roll;
            }
        }
        return null;
    }

GPS信號

//獲取GPS信號
    public String getGPS(){
        if(flightController != null){
            DJIFlightControllerDataType.DJIFlightControllerCurrentState currentState = flightController.getCurrentState();
            if (currentState != null) {
                  return currentState.getGpsSignalStatus().value()+"";
            }
        }
        return null;
    }

實現和onboard SDK的數據透傳

發送數據到onboard SDK device
1、獲取flightController 對象，如上所示；
2、通過flightController對象調用響應函數實現數據發送；

public void sendDataToOnboard(byte[] data){
            if(flightController.isOnboardSDKDeviceAvailable()){
                flightController.sendDataToOnboardSDKDevice(data, new DJIBaseComponent.DJICompletionCallback() {
                    @Override
                    public void onResult(DJIError djiError) {
                        if(djiError!=null) {
                            VirtualStickApplication.logError("SendDataToOnBoard error:", djiError);
                        }else{
                            VirtualStickApplication.logInfo("發送指令成功！");
                        }
                    }
                });
            }
        }
    }

從onboard SDK獲取數據
1、獲取flightController 對象，如上所示；
2、通過flightController對象調用響應函數實現數據回傳；

/**
*設置回調接口
*/
flightController.setReceiveExternalDeviceDataCallback(flightControllerReceivedDataFromExternalDeviceCallback);
/**
*初始化並接受回傳數據
*/
 flightControllerReceivedDataFromExternalDeviceCallback = new DJIFlightControllerDelegate.FlightControllerReceivedDataFromExternalDeviceCallback() {
            @Override
            public void onResult(byte[] bytes) {

            }
        };

註意事項：
1、在向onboard SDK device發送數據時，發送的數據需要調用String.getbytes()，轉換為byte[]類型的數據；
2、在onboard device端，由於接收到的數據為int8類型的，因此需要強制轉換為char類型的數據，再減去 ‘0’才可得到發送的值；
3、接收到的數據需要進行組裝才可得到大於一位的數據。

[Github鏈接](https://github.com/MrJoeyM/sky-app)

Dji Mobile SDK 基礎實現（二）