Question

我是android中的新手。我想从列表视图中选择一个获取和存储项目ID。该项目列表已经从mysql数据库中检索。我该怎么做？这是我的代码。

ProjectSelect

public class ProjectSelect extends AppCompatActivity {

Toolbar mToolbar;
int sempid;
private ListView ProjectList;
String a;

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

    mToolbar = (Toolbar)findViewById(R.id.project_select_bar);
    setSupportActionBar(mToolbar);
    getSupportActionBar().setTitle("SELECT A PROJECT");

    GlobalVariable g = (GlobalVariable)getApplicationContext();
    sempid=g.getEmpid();
    Log.d("project emp",sempid+"");


    ProjectList = (ListView)findViewById(R.id.projectSelect);
    getProject("http://www.mybusket.com/pmsapp/webs/get_all_project.php?vempid="+sempid+"");
}

private void getProject(final String webUrlService){
    class GetJSON extends AsyncTask<Void, Void, String>{

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            try {
                LoadIntoListView(s);
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }

        @Override
        protected String doInBackground(Void... voids) {
            try {
                URL url = new URL(webUrlService);
                HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                StringBuilder sb = new StringBuilder();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream()));
                String json;
                while ((json = bufferedReader.readLine()) != null) {
                    sb.append(json + "\n");
                }
                return sb.toString().trim();
            } catch (Exception e) {
                return null;
            }
        }
    }
    GetJSON getJSON = new GetJSON();
    getJSON.execute();
}

private void LoadIntoListView(String json) throws JSONException{
    JSONObject jsonObject = new JSONObject(json);
    if (jsonObject != null){
        JSONArray jsonArray = jsonObject.getJSONArray("project");
        final String[] project = new String[jsonArray.length()];
        for (int i = 0; i <jsonArray.length(); i ++){
            JSONObject obj = jsonArray.getJSONObject(i);
            project[i] = obj.getString("projectname");
        }
        final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, project);
        ProjectList.setAdapter(arrayAdapter);
        ProjectList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                a = ProjectList.getItemAtPosition(position).toString();
                Log.e("pname",a+"");

            }
        });

    }
}

我想将所选的项目ID存储在全局变量类中。我已经从mysql数据库中检索了所有项目。请帮助我。

Answer 1

使用hasMap创建一个单例类，并将值临时存储在hasmap中。当您选择一个值时，将该值添加到类中并在需要时检索它。

public class IdClass {
    private Map<Integer, String> clickedIDs = new HashMap<>();
    private static IdClass idClass;

    public static IdClass getIdClass() {
        if (idClass == null) {
            idClass = new IdClass();
        }
        return idClass;
    }

    public void addId(int id,String idValue) {
        clickedIDs.put(id,idValue);

    }

    public String getId(int id) {
        return clickedIDs.get(id);
    }
}

当您点击某个项目时

ProjectList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
      @Override
      public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

          //Storing inside the IdClass
          IdClass.getIdClass().addId(position,ProjectList.getItemAtPosition(position).toString());
          Log.e("pname",a+"");

      }
});

Answer 2

尝试以下代码

final String[] project = new String[jsonArray.length()];

final String[] projectId = new String[jsonArray.length()]; // create array to store id

for (int i = 0; i <jsonArray.length(); i ++){
        JSONObject obj = jsonArray.getJSONObject(i);
        project[i] = obj.getString("projectname");

        projectId[i] = obj.getString("projectid");// stroe id
    }

最后点击下面的项目点击

 a = projectId[postion];

Answer 3

你可以对你有兴趣获取id的每个视图做一件事setClickListener。当调用该视图的回调方法时，它将返回如下面代码中所述的视图。

ivMenu.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            //when this method is called use below code
             v.getId();
        }
    })

如果你想获得Activity上的视图的id，那么你可以再做一件事。将此以下属性设置为您有兴趣获取ID的视图

android:onClick="someMethod"

单击具有上述属性的视图时，它将调用属性中提到的方法。您需要在活动中定义方法，如下所述

public void someMethod(View view) {
     view.getId(); //and done
}

从listview获取所选的商品ID

3 个答案: