Question

我想onItem单击列表视图并获取DetailsPage以显示详细信息，但它得到null。 ListView中的项目是图片网址，名称和地址。 DetailsPage中的项目是图像URL，名称，地址，联系人和类别。

Image of the view on my phone when get null

这是我的ListViewPage

public class ImageListActivity extends AppCompatActivity {

private DatabaseReference mDatabaseRef;
private List<ImageUpload> imgList;
private ListView lv;
private ImageListAdapter adapter;
private ProgressDialog progressDialog;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_image_list);
    imgList = new ArrayList<>();
    lv = (ListView) findViewById(R.id.listViewImage);
    progressDialog = new ProgressDialog(this);
    progressDialog.setMessage("Please wait loading list image...");
    progressDialog.show();

    mDatabaseRef = FirebaseDatabase.getInstance().getReference(WorkshopsInfoActivity.FB_DATABASE_PATH);

    mDatabaseRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            progressDialog.dismiss();
            for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                ImageUpload img = snapshot.getValue(ImageUpload.class);
                imgList.add(img);
            }
            adapter = new ImageListAdapter(ImageListActivity.this, R.layout.image_item, imgList);
            lv.setAdapter(adapter);
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

            progressDialog.dismiss();
        }
    });
    lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
            Intent intent = new Intent(getApplicationContext(), DetailsOfWorkshops.class);
            startActivity(intent);
        }
    });
}}

这是我的详情页面

public class DetailsOfWorkshops extends AppCompatActivity {

DatabaseReference mDatabaseRef;
List<ImageUpload> listImage;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_details_of_workshops);
    mDatabaseRef = FirebaseDatabase.getInstance().getReference(WorkshopsInfoActivity.FB_DATABASE_PATH);
    mDatabaseRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            ImageUpload img = dataSnapshot.getValue(ImageUpload.class);

            String name = img.getName();
            String address = img.getAddress();
            String contact = img.getContact();
            String category = img.getCategory();


            final TextView textViewDetails = (TextView) findViewById(R.id.tvName);
            String string = "Name: " + name + "\nAddress: " + address + "\nContact: " + contact + "\nCategory: " + category + "\n\n";
            textViewDetails.setText(string);
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });
}}

Answer 1

您不向详细信息类发送任何内容：

Intent intent = new Intent(getApplicationContext(), DetailsOfWorkshops.class);
        startActivity(intent);

尝试使用：

YourClass item = (YourClass) adapterView.getAdapter().getItem(position);
Intent intent = new Intent(getApplicationContext().this, DetailsOfWorkshops.class);
Bundle bundle = new Bundle();
bundle.putString("valueName", value);
intent.putExtra("MyPackage", bundle);
startActivity(intent);

Answer 2

我们需要通过intent将ActivityOne中的一些数据发送到ActivityTwo，然后在ActivityTwo中访问该数据并将其设置为所需的textview。

检查ActivityOne中的以下代码。

public class ImageListActivity extends AppCompatActivity {

private DatabaseReference mDatabaseRef;
public List<ImageUpload> imgList;
private ListView lv;
private ImageListAdapter adapter;
private ProgressDialog progressDialog;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_image_list);
    imgList = new ArrayList<>();
    lv = (ListView) findViewById(R.id.listViewImage);
    progressDialog = new ProgressDialog(this);
    progressDialog.setMessage("Please wait loading list image...");
    progressDialog.show();

    mDatabaseRef = FirebaseDatabase.getInstance().getReference(WorkshopsInfoActivity.FB_DATABASE_PATH);

    mDatabaseRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            progressDialog.dismiss();
            for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                ImageUpload img = snapshot.getValue(ImageUpload.class);
                imgList.add(img);
            }
            adapter = new ImageListAdapter(ImageListActivity.this, R.layout.image_item, imgList);
            lv.setAdapter(adapter);
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

            progressDialog.dismiss();
        }
    });
    lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

            ImageUpload itemData = imgList.get(i);
            Intent intent = new Intent(getApplicationContext(), DetailsOfWorkshops.class);
            intent.putExtra("name", itemData.getName());
            intent.putExtra("address", itemData.getAddress());
            intent.putExtra("contact", itemData.getContact());    
            intent.putExtra("category", itemData.getCatogory());    
            startActivity(intent);
        }
    });
}}

查看ActivityTwo中的一些更改

public class DetailsOfWorkshops extends AppCompatActivity {

DatabaseReference mDatabaseRef;
List<ImageUpload> listImage;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_details_of_workshops);

    String name = getIntent().getStringExtra("name");
    String address = getIntent().getStringExtra("address");
    String contact = getIntent().getStringExtra("contact");
    String category = getIntent().getStringExtra("category");


    TextView textViewDetails = (TextView) findViewById(R.id.tvName);
    String string = "Name: " + name + "\nAddress: " + address + "\nContact: " + contact + "\nCategory: " + category + "\n\n";
    textViewDetails.setText(string);

    mDatabaseRef = FirebaseDatabase.getInstance().getReference(WorkshopsInfoActivity.FB_DATABASE_PATH);
    mDatabaseRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            ImageUpload img = dataSnapshot.getValue(ImageUpload.class);
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });
}}

希望这有用。

@Rajesh

Answer 3

尝试使用onItemSelected侦听器而不是onItemClick侦听器，这将为您提供可以帮助您获取所需数据的特定对象的位置然后你可以发送具有适当值的额外内容

        ImageUpload itemData = imgList.get(pos);
        Intent intent = new Intent(getApplicationContext(), 
        DetailsOfWorkshops.class);
        intent.putExtra("name", itemData.getName());
        intent.putExtra("address", itemData.getAddress());
        intent.putExtra("contact", itemData.getContact());    
        intent.putExtra("category", itemData.getCatogory());    
        startActivity(intent);

OnClick侦听器适用于整个视图，而不是特定元素.OnSelected给出了您在listView上选择的项目的位置

无法使用onItemClickListener获取数据

3 个答案: