Question

我有一个片段。单击图像后，我开始活动。但是我一直收到这个错误

Unable to start activity ComponentInfo{com.flag.app/com.flag.app.app.activity.MarkerDetailsActivity}:
java.lang.NullPointerException: Attempt to invoke virtual method 'com.flag.app.app.model.Image com.flag.app.app.model.Marker.getImage()' 
on a null object reference

这是我的活动

public class MarkerDetailsActivity extends AppCompatActivity {

public static Intent getStartIntent(Context context, Marker marker) {
    Intent startIntent = new Intent(context, MarkerDetailsActivity.class);
    startIntent.putExtra(EXTRA_MARKER, marker);
    return startIntent;
}


ImageView mImageView;
TextView mNameTextView;
Marker mMarker;
MapView mMapView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_details_marker);
    mMarker = getIntent().getParcelableExtra(EXTRA_MARKER);

    mImageView = findViewById(R.id.image_view);
    mMapView = findViewById(R.id.map_view);
    mMapView.onCreate(savedInstanceState);
    bindMarker(mMarker);
}

private void bindMarker(Marker marker) {
    Picasso.with(mImageView.getContext())
            .load(marker.getImage().getUrl())
            .into(mImageView);
    mAuthorTextView.setText(marker.getAuthor());
    mDescriptionTextView.setText(marker.getDescription());
    mDateTextView.setText(marker.getDate());

}
   }

如何解决？

Answer 1

检查是否为空值。

private void bindMarker(Marker marker) {
if(marker != null){
    Picasso.with(mImageView.getContext())
            .load(marker.getImage().getUrl())
            .into(mImageView);
    mAuthorTextView.setText(marker.getAuthor());
    mDescriptionTextView.setText(marker.getDescription());
    mDateTextView.setText(marker.getDate());

}}

Answer 2

private void bindMarker(Marker marker) {
    if(marker!=null){
        if(marker.getImage()!=null) {
            Picasso.with(mImageView.getContext())
                    .load(marker.getImage().getUrl())
                    .into(mImageView);
        }
        mAuthorTextView.setText(marker.getAuthor());
        mDescriptionTextView.setText(marker.getDescription());
        mDateTextView.setText(marker.getDate());
    }
}

使用Marker对象是否为空之前必须检查

空对象参考android。

2 个答案: