Android 工作室使用 onItemClickListener (Firestore id) 获取 ListView 数组项值

Question

(click for image)I think it will be better if I contain an image, all of these data are in firestore. I want to display the correct doc id when I click each of them, right now it can only display the last doc id which is the earlyiest data since I orderBy in time

在这种情况下，我想获取我为每次文档快照添加到数组中的 firestore id 运行。例如：点击 ListView 的第一项并 Toast firestore 中数据的正确文档 ID。

在我的代码中，当我点击那里时，它只能获得文档 ID 的最后一个。顺便说一句，如果我将它放入快照，idlv 运行良好。 getString 并显示它，但我只想获取下一页的 ID 和意图，以便我可以加载文档的数据。

抱歉英语不好和新手编码（我知道它真的很乱）

问题可能出在 itemOnclick 函数中 ("id is"+idlv)

public class announce_main extends AppCompatActivity {
    Button button7;
    ListView lv1;
    ArrayList<itemAnnounce> ar = new ArrayList<>();
    String userID,idlv;
    FirebaseAuth firebaseAuth;
    FirebaseFirestore firebaseFirestore;



    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.announce_listview);
        button7 = findViewById(R.id.button7);
      //  item = (item) getIntent().getSerializableExtra("item");


        firebaseAuth = FirebaseAuth.getInstance();
        firebaseFirestore = FirebaseFirestore.getInstance();
        userID = firebaseAuth.getCurrentUser().getUid();
        firebaseFirestore.collection("announcement").orderBy("createdAt", Query.Direction.DESCENDING).addSnapshotListener((documentSnapshots, error) -> {
            ar.clear();

                for (DocumentSnapshot snapshot : documentSnapshots){
                    idlv = snapshot.getId();
                Timestamp timestamp = (Timestamp) snapshot.getData().get("createdAt");
                Date date = timestamp.toDate();
                String date2 = date.toString();
                String artLv = snapshot.getString("artLevel");
                Log.d("TAG", " artLevel is" + artLv);


                if(artLv.equals("緊急公告")){

                    ar.add(new itemAnnounce(R.drawable.alarm, snapshot.getString("title"),"by "+snapshot.getString("createdBy")+ " 類型:"+snapshot.getString("artLevel"),date2,snapshot.getString("content"),idlv));
                }else if(artLv.equals("議題公告")){

                    ar.add(new itemAnnounce(R.drawable.newspaper, snapshot.getString("title"),"by "+snapshot.getString("createdBy")+ " 類型:"+snapshot.getString("artLevel"),date2,snapshot.getString("content"),idlv));
                }else{

                    ar.add(new itemAnnounce(R.drawable.teatime, snapshot.getString("title"),"by "+snapshot.getString("createdBy")+ " 類型:"+snapshot.getString("artLevel"),date2,snapshot.getString("content"),idlv));
                }

            }
            adapterAnnounce adapterAnnounce = new adapterAnnounce(getApplicationContext(), R.layout.list_row_announce, ar);
            adapterAnnounce.notifyDataSetChanged();
            lv1.setAdapter(adapterAnnounce);

            lv1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                    Toast.makeText(announce_main.this, "id is"+ idlv, Toast.LENGTH_SHORT).show();
                }
            });
        });
        lv1 = findViewById(R.id.lv2);

button7.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        startActivity(new Intent(announce_main.this, HomePageActivity.class));
    }
});





    }

Answer 1

您不应该像那样访问 idlv，它总是会为您提供最后一个项目 ID。理想情况下你应该做的如下

lv1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                String selectedObj = ar.get(postion) // this will get you selected obj of itemAnnounce
                String selectedId = selectedObj.get("<property name of itemAnnounce where you are assigning idlv>")  
                Toast.makeText(announce_main.this, "id is"+ selectedId, Toast.LENGTH_SHORT).show();
            }
        });

Android 工作室使用 onItemClickListener (Firestore id) 获取 ListView 数组项值

Android studio getting ListView array item value with onItemClickListener (Firestore id)

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onitemclicklistener