Java 它';s在解析json时引发异常
我正在使用android studio编程,希望通过以下链接解析json: 然后把细节放在我创建的一个类中,这个类命名细节并有一个列表,但它抛出了一个异常。我该怎么办? 主要活动:Java 它';s在解析json时引发异常,java,android,json,android-studio,Java,Android,Json,Android Studio,我正在使用android studio编程,希望通过以下链接解析json: 然后把细节放在我创建的一个类中,这个类命名细节并有一个列表,但它抛出了一个异常。我该怎么办? 主要活动: public class MainActivity extends ActionBarActivity { static ArrayList<Details> details= new ArrayList<>(); @Override protected void onCreate(Bund
public class MainActivity extends ActionBarActivity {
static ArrayList<Details> details= new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new myserver2().execute((String[]) null);
Adapter adptor=new Adapter(this,details);
ListView l= (ListView) findViewById(R.id.listview);
l.setAdapter(adptor);
Log.i("**(*si","si");
}
private class myserver2 extends AsyncTask<String,String,String> {
String s;
@Override
protected String doInBackground(String... params) {
HttpClient client = new DefaultHttpClient();
HttpGet hp = new HttpGet("http://jsonplaceholder.typicode.com/posts");
try
{
HttpResponse r = client.execute(hp);
HttpEntity ent = r.getEntity();
String s = EntityUtils.toString(ent);
JSONArray array = new JSONArray(s);
JSONObject obj = new JSONObject();
for(int i=0;i<array.length();i++){
Details d = null;
obj=array.getJSONObject(i);
d.setId(Integer.parseInt(obj.getString("id")));
d.setUserid(Integer.parseInt(obj.getString("userId")));
d.setBody(obj.getString("body"));
d.setTitle(obj.getString("title"));
details.add(d);
}
} catch (
IOException e
)
{
e.printStackTrace();
} catch (
JSONException e
)
{
e.printStackTrace();
}
return null;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
}
和适配器:
public class Adapter extends ArrayAdapter<Details> {
Context c;
ArrayList<Details> details;
public Adapter(Context context, ArrayList<Details> objects) {
super(context, R.layout.item, objects);
c=context;
details=objects;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater= (LayoutInflater) c.getSystemService(c.LAYOUT_INFLATER_SERVICE);
View v=inflater.inflate(R.layout.item,parent,false);
TextView body= (TextView) v.findViewById(R.id.body);
TextView title= (TextView) v.findViewById(R.id.title);
String body2= details.get(position).getBody();
String title2= details.get(position).getTitle();
body.setText(body2);
title.setText(title2);
return v;
}
在这两行输入:
d.setId(Integer.parseInt(obj.getString("id")));
及
私有类myserver2扩展了异步任务{
您应该检查:
d.setId(Integer.parseInt(obj.getString(“id”));
- 如果此时d为空
- 如果obj在该时刻为空
- 如果键“id”在对象中,并且是表示整数的字符串
如果您在调试时考虑到了所有这些,最有可能的是您可以找到错误,或者至少向我们提供更多信息。您可以分享异常的跟踪信息吗?@AndreuRodrígueziDonaire done!仅此而已?您应该使用我在回答中提供的信息进行调试首先处理所有异常更改}catch(IOException e){e.printStackTrace();}catch(JSONException e){e.printStackTrace();}TO:catch(Exception e){}然后检查json数据是否真正输出json..执行此操作
Caused by: java.lang.NullPointerException
at com.etsiamak.practice5.MainActivity$myserver2.doInBackground(MainActivity.java:56)
at com.etsiamak.practice5.MainActivity$myserver2.doInBackground(MainActivity.java:37)
d.setId(Integer.parseInt(obj.getString("id")));
private class myserver2 extends AsyncTask<String,String,String> {