Android -boolean com.google.android.gms.common.api.GoogleApiClient.isConnected()' 在空对象引用上

Question

我的片段类出现错误

java.lang.NullPointerException：尝试在 fragment.HomeFragment.onResume 的空对象引用上调用虚拟方法“boolean com.google.android.gms.common.api.GoogleApiClient.isConnected()”

这是我在 HomeFragment 上的部分代码

private GoogleApiClient mGoogleApiClient;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
        mCurrentLocation = savedInstanceState.getParcelable(KEY_LOCATION);
        mCameraPosition = 
savedInstanceState.getParcelable(KEY_CAMERA_POSITION);
    }        buildGoogleApiClient();
}

@Override
public void onResume() {
    super.onResume();
    if (mGoogleApiClient.isConnected()) {
        getDeviceLocation();
    }
    updateMarkers();
}

    private synchronized void buildGoogleApiClient() {
    GoogleApiClient.Builder builder = new GoogleApiClient.Builder(getActivity());
    mGoogleApiClient = builder.build();
    //builder.enableAutoManage(this /* FragmentActivity */, this /* OnConnectionFailedListener */);
    builder.addConnectionCallbacks(this);
    builder.addApi(LocationServices.API);
    builder.addApi(Places.GEO_DATA_API);
    builder.addApi(Places.PLACE_DETECTION_API);
    builder.build();
    createLocationRequest();
}

我也实现了

1. OnMapReadyCallback
2. GoogleApiClient.ConnectionCallbacks
3. GoogleApiClient.OnConnectionFailedListener
4. 位置监听器
5. DirectionFinderListener

有人可以帮我解决这个问题吗？

Answer 1

您需要保留对您正在构建的GoogleApiClient 实例的引用。所以应该是：

private void buildGoogleApiClient() {
    mGoogleApiClient = new GoogleApiClient.Builder(getActivity())
        .addConnectionCallbacks(this)
        .addApi(LocationServices.API)
        .addApi(Places.GEO_DATA_API)
        .addApi(Places.PLACE_DETECTION_API)
        .build();
    createLocationRequest();
}