我是 android 和 java 的新手。最近我在使用 baseadapter 将获取的 json 数据显示到 listview 时遇到问题。
起初我用过这段代码
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new TheTask().execute();
}
class TheTask extends AsyncTask<Void,Void,String>
{
@Override
protected String doInBackground(Void... params) {
String str = null;
try
{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://10.0.2.2/BSDI/show.php");
HttpResponse response = httpclient.execute(httppost);
str = EntityUtils.toString(response.getEntity());
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return str;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
String response = result.toString();
try {
ArrayList<String> stringArray = new ArrayList<String>();
JSONArray new_array = new JSONArray(response);
for(int i = 0, count = new_array.length(); i< count; i++)
{
try {
JSONObject jsonObject = new_array.getJSONObject(i);
stringArray.add(jsonObject.getString("title").toString());
}
catch (JSONException e) {
e.printStackTrace();
}
}
ArrayAdapter<String> adapter = new ArrayAdapter<String> (MainActivity.this,R.layout.test_tuh,stringArray);
ListView list= (ListView) findViewById(R.id.listView1);
list.setAdapter(adapter);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
//tv.setText("error2");
}
}
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
此代码成功显示获取的 json 数据。但它只显示一行。我需要在列表视图中多于一（两）行。所以我尝试过这段代码
它不起作用，它显示空白屏幕。
我的代码如下，
class TheTask extends AsyncTask<Void,Void,String>
{
@Override
protected String doInBackground(Void... params) {
String str = null;
try
{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://10.0.2.2/BSDI/show.php");
HttpResponse response = httpclient.execute(httppost);
str = EntityUtils.toString(response.getEntity());
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return str;
}
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
String response = result.toString();
try {
arrayList=new ArrayList<get_set>();
ArrayList<String> stringArray = new ArrayList<String>();
JSONArray new_array = new JSONArray(response);
for(int i = 0, count = new_array.length(); i< count; i++)
{
try {
JSONObject jsonObject = new_array.getJSONObject(i);
stringArray.add(jsonObject.getString("title").toString());
}
catch (JSONException e) {
e.printStackTrace();
}
}
ListView listView;
adap= new BaseAdapter() {
LayoutInflater inflater=(LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
@Override
public View getView(int position, View view, ViewGroup viewgroup) {
if (view==null) {
view=inflater.inflate(R.layout.bsdi, null);
}
TextView title_tuh=(TextView) view.findViewById(R.id.title1);
TextView notice_tuh=(TextView) view.findViewById(R.id.notice1);
title_tuh.setText(arrayList.get(position).getTitle());
notice_tuh=.setText(arrayList.get(position).getNotice());
return view;
}
@Override
public long getItemId(int arg0) {
// TODO Auto-generated method stub
return 0;
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return arrayList.get(position);
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return arrayList.size();
}
};
listView=(ListView) findViewById(R.id.listView1);
listView.setAdapter(adap);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
//tv.setText("error2");
}
}
据我所知，问题就在这里
ArrayList<String> stringArray = new ArrayList<String>();
JSONArray new_array = new JSONArray(response);
for(int i = 0, count = new_array.length(); i< count; i++)
{
try {
JSONObject jsonObject = new_array.getJSONObject(i);
stringArray.add(jsonObject.getString("title").toString());
}
catch (JSONException e) {
e.printStackTrace();
}
}
到目前为止，我猜测提取的 json 数据存储在字符串数组中，但稍后不会使用。如果我尝试像这样使用它，则会出现错误
title_tuh.setText(stringArray .get(position).getTitle());
notice_tuh=.setText(stringArray .get(position).getNotice());
如果我尝试不使用
ArrayList stringArray = new ArrayList();
and use
数组列表=新的数组列表();相反，像这样我也会收到错误。
arrayList=new ArrayList<get_set>();
JSONArray new_array = new JSONArray(response);
//JSONArray jsonArray = new JSONArray();
for(int i = 0, count = new_array.length(); i< count; i++)
{
try {
JSONObject jsonObject = new_array.getJSONObject(i);
arrayList.add(jsonObject.getString("title").toString());
// String in = mInflater.inflate(R.layout.custom_row_view, null);
}
catch (JSONException e) {
e.printStackTrace();
}
}
我不知道如何解决这个问题。我看过很多在线教程，但这些对我没有帮助。请帮我。
