此问题也发布在这里：
https://github.com/dji-sdk/Mobile-SDK-Android/issues/410#thread-subscription-status
与https://github.com/DJI-Mobile-SDK-Tutorials/Android-VideoStreamDecodingSample/issues/30
有关此问题发生在修改后的UX示例中。
应用程序调试日志显示以下错误，该错误似乎在UserAccountManager.getInstance().logIntoDJIUserAccount时发生
已执行-省略此方法后，应用运行良好-但是没有视频流。
**E/AndroidRuntime: FATAL EXCEPTION: dji_sdk_callback_thread
Process: com.dji.uxsdkdemo, PID: 26848
java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources$Theme android.content.Context.getTheme()' on a null object reference
at android.content.ContextWrapper.getTheme(ContextWrapper.java:125)
at android.app.Dialog.<init>(Dialog.java:193)
at android.app.Dialog.<init>(Dialog.java:163)
at dji.internal.useraccount.a.a.<init>(Unknown Source:11)
at dji.internal.useraccount.a.a(Unknown Source:2)
at dji.internal.useraccount.a.a(Unknown Source:19)
at dji.sdk.useraccount.UserAccountManager.logIntoDJIUserAccount(Unknown Source:46)
at dji.sdk.useraccount.UserAccountManager.logIntoDJIUserAccount(Unknown Source:1)
at com.dji.uxsdkdemo.DemoApplication.loginAccount(DemoApplication.java:139)
at com.dji.uxsdkdemo.DemoApplication.access$000(DemoApplication.java:22)
at com.dji.uxsdkdemo.DemoApplication$1.onRegister(DemoApplication.java:75)
at dji.internal.b.a$11.run(Unknown Source:4)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:198)
at android.os.HandlerThread.run(HandlerThread.java:65)**
我们正在使用4.9版的SDK
(
compile ('com.dji:dji-uxsdk:4.9')
provided ('com.dji:dji-sdk-provided:4.9')
)
Windows 10和M600PRO无人机。
IDE是Android Studio，API级别为27。移动设备是具有Android 8.1的Oppo R17。
以下文件“ Demoapplication.java”供您参考：
package com.dji.uxsdkdemo;
import android.app.Application;
import android.content.Context;
import android.content.Intent;
import android.os.Build;
import android.os.Handler;
import android.os.Looper;
import android.support.v4.content.ContextCompat;
import android.util.Log;
import android.widget.Toast;
import dji.common.error.DJIError;
import dji.common.error.DJISDKError;
import dji.common.useraccount.UserAccountState;
import dji.common.util.CommonCallbacks;
import dji.sdk.base.BaseComponent;
import dji.sdk.base.BaseProduct;
import dji.sdk.sdkmanager.DJISDKManager;
import dji.sdk.useraccount.UserAccountManager;
public class DemoApplication extends Application {
public static final String FLAG_CONNECTION_CHANGE = "uxsdk_demo_connection_change";
private static BaseProduct mProduct;
private Handler mHandler;
private DJISDKManager.SDKManagerCallback mDJISDKManagerCallback;
private Application instance;
public void setContext(Application application) {
instance = application;
}
@Override
public Context getApplicationContext() {
return instance;
}
public DemoApplication() {
}
/**
* This function is used to get the instance of DJIBaseProduct.
* If no product is connected, it returns null.
*/
public static synchronized BaseProduct getProductInstance() {
if (null == mProduct) {
mProduct = DJISDKManager.getInstance().getProduct();
}
return mProduct;
}
@Override
public void onCreate() {
super.onCreate();
mHandler = new Handler(Looper.getMainLooper());
/**
* When starting SDK services, an instance of interface DJISDKManager.DJISDKManagerCallback will be used to listen to
* the SDK Registration result and the product changing.
*/
mDJISDKManagerCallback = new DJISDKManager.SDKManagerCallback() {
@Override
public void onRegister(DJIError error) {
//isRegistrationInProgress.set(false);
if (error == DJISDKError.REGISTRATION_SUCCESS) {
DJISDKManager.getInstance().startConnectionToProduct();
Toast.makeText(getApplicationContext(), "SDK registration succeeded!", Toast.LENGTH_LONG).show();
loginAccount();
} else {
Toast.makeText(getApplicationContext(),
"SDK registration failed, check network and retry!",
Toast.LENGTH_LONG).show();
}
}
@Override
public void onProductDisconnect() {
Toast.makeText(getApplicationContext(),
"product disconnect!",
Toast.LENGTH_LONG).show();
}
@Override
public void onProductConnect(BaseProduct product) {
Toast.makeText(getApplicationContext(),
"product connect!",
Toast.LENGTH_LONG).show();
}
@Override
public void onComponentChange(BaseProduct.ComponentKey key,
BaseComponent oldComponent,
BaseComponent newComponent) {
// Toast.makeText(getApplicationContext(),
// key.toString() + " changed",
// Toast.LENGTH_LONG).show();
}
};
//Check the permissions before registering the application for android system 6.0 above.
int permissionCheck = ContextCompat.checkSelfPermission(getApplicationContext(), android.Manifest.permission.WRITE_EXTERNAL_STORAGE);
int permissionCheck2 = ContextCompat.checkSelfPermission(getApplicationContext(), android.Manifest.permission.READ_PHONE_STATE);
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M || (permissionCheck == 0 && permissionCheck2 == 0)) {
//This is used to start SDK services and initiate SDK.
DJISDKManager.getInstance().registerApp(getApplicationContext(), mDJISDKManagerCallback);
} else {
Toast.makeText(getApplicationContext(), "Please check if the permission is granted.", Toast.LENGTH_LONG).show();
}
}
private void loginAccount(){
UserAccountManager.getInstance().logIntoDJIUserAccount(this,
new CommonCallbacks.CompletionCallbackWith<UserAccountState>() {
@Override
public void onSuccess(final UserAccountState userAccountState) {
Log.e("TAG", "Login Success");
}
@Override
public void onFailure(DJIError error) {
Log.e("TAG", "Login Error:" + error.getDescription());
}
});
}
private void notifyStatusChange() {
mHandler.removeCallbacks(updateRunnable);
mHandler.postDelayed(updateRunnable, 500);
}
private Runnable updateRunnable = new Runnable() {
@Override
public void run() {
Intent intent = new Intent(FLAG_CONNECTION_CHANGE);
getApplicationContext().sendBroadcast(intent);
}
};
}