Question

我的代码目前正在工作并显示数据库中的一个项目，但在线查看后，我将数据放入适配器中，但它只显示数据库中的第一项。我应该更改什么才能显示数据库的所有项目？

MarksActivity.java

val

Answer 1

最后一个值必须显示。我建议你初始化上面循环的String [] Status并在循环内添加状态。你会得到结果！

创建一个模型类作为DemoObject：

public class DemoObject {
    private String nota;

    public String getNota() {
        return nota;
    }

    public void setNota(String nota) {
        this.nota = nota; 
    }
}

现在，

private void showJSON(String response){
            DemoObject demoObject = new DemoObject();
            List<DemoObject> list = new ArrayList();
            try {
                JSONObject jsonObject = new JSONObject(response);
                JSONArray result = jsonObject.getJSONArray(Config.JSON_ARRAY);
                for(i=0;i<result.length();i++)
                    Log.v("Result--",""+result.getString(i));
                JSONObject collegeData = result.getJSONObject(0);
                demoObject.setNota(collegeData.getString(Config.KEY_NAME));
                list.add(demoObject);
            } catch (JSONException e) {
                e.printStackTrace();
            }

最后，

textViewResult.setAdapter(new ArrayAdapter<String>(MarksActivity.this,
                    android.R.layout.simple_list_item_1, list));

Answer 2

问题出在showJson方法中你需要在开头初始化字符串数组并在那里添加项目

private void showJSON(String response){

        List<String> status = new ArrayList<String>(); // since you don't know exactly how many elements are there in the json array
        String nota="";
        String materie="";
        String profesor = "";
        try {
            JSONObject jsonObject = new JSONObject(response);
            JSONArray result = jsonObject.getJSONArray(Config.JSON_ARRAY);
            for(i=0;i<result.length();i++) {
                Log.v("Result--",""+result.getString(i));
                JSONObject collegeData = result.getJSONObject(i);
                nota = collegeData.getString(Config.KEY_NAME);
                materie = collegeData.getString(Config.KEY_ADDRESS);
                profesor = collegeData.getString(Config.KEY_VC);
                status.add("Nota:\t"+nota+"\nMaterie:\t" +materie+ "\nProfesor:\t"+ profesor);
            }

        } catch (JSONException e) {
            e.printStackTrace();

        }


        textViewResult.setAdapter(new ArrayAdapter<String>(MarksActivity.this,
                android.R.layout.simple_list_item_1, status));
    }

Answer 3

根据我的理解，你的showJSON方法应如下所示：

private void showJSON(String response){

    String nota="";
    String materie="";
    String profesor = "";
    String[] status = null; 
    try {
        JSONObject jsonObject = new JSONObject(response);
        JSONArray result = jsonObject.getJSONArray(Config.JSON_ARRAY);
        status = new String[result.length()];

        for(i=0;i<result.length();i++) {
            Log.v("Result--",""+result.getString(i));

            JSONObject collegeData = result.getJSONObject(i);
            nota = collegeData.getString(Config.KEY_NAME);
            materie = collegeData.getString(Config.KEY_ADDRESS);
            profesor = collegeData.getString(Config.KEY_VC);

            status[i] = "Nota:\t"+nota+"\nMaterie:\t" +materie+ "\nProfesor:\t"+ profesor;       
        }


    } catch (JSONException e) {
        e.printStackTrace();

    }
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(MarksActivity.this,
            android.R.layout.simple_list_item_1, android.R.id.text1, status);
    textViewResult.setAdapter(adapter);
}

Answer 4

private void getData() {
        String nume = editTextId.getText().toString().trim();
        if (nume.equals("")) {
            Toast.makeText(this, "Numele tau", Toast.LENGTH_LONG).show();
            return;
        }
        loading = ProgressDialog.show(this,"Te rugam asteapta","Fetching...",false,false);

        String url = Config.DATA_URL+editTextId.getText().toString().trim();

        StringRequest stringRequest = new StringRequest(url, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                loading.dismiss();
                showJSON(response);
            }
        },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(MarksActivity.this, error.getMessage(),Toast.LENGTH_LONG).show();
                    }
                });

        RequestQueue requestQueue = Volley.newRequestQueue(this);
        requestQueue.add(stringRequest);
    }



    private void showJSON(String response){

    List<String> status = new ArrayList<String>(); // since you don't know exactly how many elements are there in the json array
    String nota="";
    String materie="";
    String profesor = "";
    try {
        JSONObject jsonObject = new JSONObject(response);
        JSONArray result = jsonObject.getJSONArray(Config.JSON_ARRAY);
        for(i=0;i<result.length();i++) {
            Log.v("Result--",""+result.getString(i));
        JSONObject collegeData = result.getJSONObject(i);
        nota = collegeData.getString(Config.KEY_NAME);
        materie = collegeData.getString(Config.KEY_ADDRESS);
        profesor = collegeData.getString(Config.KEY_VC);
        status.add("Nota:\t"+nota+"\nMaterie:\t" +materie+ "\nProfesor:\t"+ profesor);
        }

    } catch (JSONException e) {
        e.printStackTrace();

    }


    textViewResult.setAdapter(new ArrayAdapter<String>(MarksActivity.this,
            android.R.layout.simple_list_item_1, status));
}

在listview中显示数据库项

4 个答案: