【发布时间】：2016-02-22 08:59:56
【问题描述】：
我对android很陌生，我已经在网上搜索了3天的答案，在这里和其他地方，但运气不佳。请原谅我的愚蠢问题。 好吧，我基本上想做的是一个简单的联系人列表，其中包含 3 个字段。私人姓名、姓氏和电话号码。我从 JSON 中获取信息。 这是我的 MainActivity。
public class MainActivity extends Activity implements AdapterView.OnItemClickListener {
private static String stream = "http://cs.ash-college.ac.il/~habitbul/androidStudents.html";
CustomListAdapter adapter=new CustomListAdapter();
ListView list;
TextView firstName,lastName,number;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
adapter = new CustomListAdapter(new ArrayList<Student>(), this);
list = (ListView) findViewById(R.id.listView);
firstName=(TextView)findViewById(R.id.txtfirstname);
lastName=(TextView)findViewById(R.id.txtlastname);
number=(TextView)findViewById(R.id.txtnumber);
list.setAdapter(adapter);
list.setOnItemClickListener(this);
new myAsyncTask().execute(stream);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Object call=list.getItemAtPosition(position);
call.toString();
String uri = "tel:" + call;
Intent intent = new Intent(Intent.ACTION_DIAL);
intent.setData(Uri.parse(uri));
startActivity(intent);
}
public class myAsyncTask extends AsyncTask<String, Void, List<Student>> {
private final ProgressDialog dialog = new ProgressDialog(MainActivity.this);
@Override
protected void onPreExecute() {
super.onPreExecute();
dialog.setMessage("Downloading contacts...");
dialog.show();
}
@Override
protected List<Student> doInBackground(String... params) {
List<Student> result;
result = new ArrayList<Student>();
try {
URL u = new URL(stream);
HttpURLConnection connection = (HttpURLConnection) u.openConnection();
connection.setRequestMethod("GET");
connection.connect();
InputStream inputStream = connection.getInputStream();
// Read the stream
byte[] b = new byte[1024];
ByteArrayOutputStream output = new ByteArrayOutputStream();
while (inputStream.read(b) != -1)
output.write(b);
String JSONResp = new String(output.toByteArray());
JSONArray arr = new JSONArray(JSONResp);
for (int i = 0; i < arr.length(); i++) {
result.add(new Student(arr.getJSONObject(i)));
}
return result;
} catch (Throwable t) {
t.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(List<Student> result) {
super.onPostExecute(result);
dialog.dismiss();
adapter.setItemList(result);
adapter.notifyDataSetChanged();
}
public Student convertStudent(JSONObject obj) throws JSONException {
String firstname = obj.getString("first_name");
String lastname = obj.getString("last_name");
String number = obj.getString("phone_number");
return new Student(firstname, lastname, number);
}
}
我的 CustomListAdapter 类：
public class CustomListAdapter extends BaseAdapter {
private List<Student> studentList;
private Context context;
/************* CustomAdapter Constructor *****************/
public CustomListAdapter(ArrayList<Student> itemList, Context c)
{
this.studentList=itemList;
this.context=c;
}
public CustomListAdapter() {
}
@Override
public int getCount() {
if (studentList != null)
return studentList.size();
return 0;
}
@Override
public Student getItem(int i) {
if (studentList != null)
return studentList.get(i);
return null;
}
@Override
public long getItemId(int i) {
if (studentList != null)
return studentList.get(i).hashCode();
return 0;
}
@Override
public View getView(int i, View convertStudent, ViewGroup viewGroup) {
View cell=convertStudent;
if (cell == null) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
cell = inflater.inflate(R.layout.list_cell, null);
}
Student s = studentList.get(i);
TextView firstName = (TextView) cell.findViewById(R.id.txtfirstname);
firstName.setText(s.getFirstName());
TextView lastName = (TextView) cell.findViewById(R.id.txtlastname);
lastName.setText(s.getLastName());
TextView number = (TextView) cell.findViewById(R.id.txtnumber);
number.setText(s.getNumber());
return cell;
}
public List<Student> getItemList() {
return this.studentList;
}
public void setItemList(List<Student> itemList) {
this.studentList = itemList;
}
}
这是我的学生班：
/**Create Model to save each ListView row data.*/
public class Student {
int id;
String firstName;
String lastName;
String number;
public Student(JSONObject object) {
try {
this.id=object.getInt("1");
this.firstName = object.getString("first_name");
this.lastName = object.getString("last_name");
this.number=object.getString("phone_number");
}
catch (JSONException e) {
e.printStackTrace();
}
}
public Student(String firstname, String lastname, String number) {
this.firstName=firstname;
this.lastName=lastname;
this.number=number;
}
public String getFirstName(){
return firstName;
}
public void setFirstName(String fn){
this.firstName=fn;
}
public void setLastName(String ln){
this.lastName=ln;
}
public void setNumber(String num){
this.number=num;
}
public Student getItemList( ){
return getItemList();
}
public Student setItemList(Student s){
return s;
}
public String getNumber() {
return number;
}
public String getLastName(){
return lastName;
}
当我运行应用程序时，它是一个包含行的空列表，如下所示：
当我按下空列表中的行时，由于某种原因，我得到了所有随机数，如下所示：
如您所见，我是新手，在这里我看不到我的问题。感谢所有帮助。
【问题讨论】：
-
你能从服务器获得 JSON 响应吗？？
-
@madhusudhan 你是什么意思？我该如何检查？再说一次，你可能猜到了，我是新手。
-
您以错误的方式解析您的 json 响应。如果您看到响应，则在数组的每个元素中都有一个带有键
person的 json 对象。您需要访问它。 -
我明白了。所以我检查了你的服务器 URL ..它给出了一些 JSON 响应。所以你需要解析它并在列表视图中显示它。我对吗？
-
在您的 doInBackground 中打印 result.toString() 并检查您收到正确响应的结果
标签： android json android-asynctask onitemclicklistener