Java 关闭android程序,立即在json中运行应用程序
大家好,我写了一个程序从服务器获取数据,并用json在列表视图中显示数据 但当我启动应用程序时,应用程序立即关闭。 我检查了我的舱单,没问题,我不知道该怎么办,请帮帮我 主要活动代码:Java 关闭android程序,立即在json中运行应用程序,java,php,android,json,android-studio,Java,Php,Android,Json,Android Studio,大家好,我写了一个程序从服务器获取数据,并用json在列表视图中显示数据 但当我启动应用程序时,应用程序立即关闭。 我检查了我的舱单,没问题,我不知道该怎么办,请帮帮我 主要活动代码: package com.example.delta.travel; import android.app.ListActivity; import android.app.ProgressDialog; import android.os.AsyncTask; import android.os.Bundle;
package com.example.delta.travel;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListAdapter;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class MainActivity extends ListActivity {
private ProgressDialog pd;
JSONParser jParser=new JSONParser();
ArrayList<HashMap<String,String>> P;
JSONArray s=null;
private final String url="http://192.168.1.4/upload/travel.php";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new travel().execute();
}
class travel extends AsyncTask<String,String,String>{
@Override
protected void onPreExecute() {
super.onPreExecute();
pd=new ProgressDialog(MainActivity.this);
pd.setMessage("login");
pd.show();
}
@Override
protected String doInBackground(String... params) {
List<NameValuePair> parms=new ArrayList<>();
JSONObject json=jParser.makeHTTPRequest(url,"GET",parms);
try {
int t=json.getInt("t");
if(t==1){
s=json.getJSONArray("travel");
for(int i=0;i<s.length();i++){
JSONObject c=s.getJSONObject(i);
String companyname=c.getString("companyname");
String cod=c.getString("cod");
String bign=c.getString("bign");
String stop=c.getString("stop");
String date=c.getString("date");
String time=c.getString("time");
String price=c.getString("price");
HashMap<String,String>map=new HashMap<String,String>();
map.put("companyname",companyname);
map.put("cod",cod);
map.put("bign",bign);
map.put("stop",stop);
map.put("date",date);
map.put("time",time);
map.put("price",price);
P.add(map);
}
}else {
Toast.makeText(MainActivity.this,"No DataFound",Toast.LENGTH_SHORT).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
pd.dismiss();
runOnUiThread(new Runnable() {
@Override
public void run() {
ListAdapter adapter = new SimpleAdapter(MainActivity.this, P, R.layout.item_list,
new String[]{"companyname", "cod", "bign", "stop", "date", "time", "price"},
new int[]{R.id.companyname, R.id.cod, R.id.bign, R.id.stop, R.id.date, R.id.time1, R.id.price});
setListAdapter(adapter);
}
});
}
}
}
package com.example.delta.travel;
导入android.app.ListActivity;
导入android.app.ProgressDialog;
导入android.os.AsyncTask;
导入android.os.Bundle;
导入android.support.design.widget.FloatingActionButton;
导入android.support.design.widget.Snackbar;
导入android.support.v7.app.AppActivity;
导入android.support.v7.widget.Toolbar;
导入android.view.view;
导入android.view.Menu;
导入android.view.MenuItem;
导入android.widget.ListAdapter;
导入android.widget.simpledapter;
导入android.widget.Toast;
导入org.apache.http.NameValuePair;
导入org.json.JSONArray;
导入org.json.JSONException;
导入org.json.JSONObject;
导入java.util.ArrayList;
导入java.util.HashMap;
导入java.util.List;
公共类MainActivity扩展了ListActivity{
私营部门;
JSONParser jParser=新的JSONParser();
ArrayList P;
JSONArray s=null;
私有最终字符串url=”http://192.168.1.4/upload/travel.php";
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
新行程().execute();
}
班级旅行任务{
@凌驾
受保护的void onPreExecute(){
super.onPreExecute();
pd=新建进度对话框(MainActivity.this);
pd.setMessage(“登录”);
pd.show();
}
@凌驾
受保护的字符串doInBackground(字符串…参数){
List parms=new ArrayList();
JSONObject json=jParser.makeHTTPRequest(url,“GET”,parms);
试一试{
int t=json.getInt(“t”);
如果(t==1){
s=json.getJSONArray(“旅行”);
对于(int i=0;i
进行一些更改,看看它是否有效:
new travel().execute(url);
您的任务:
class travel extends AsyncTask<String,Void,String>{
@Override
protected void onPreExecute() {
super.onPreExecute();
pd=new ProgressDialog(MainActivity.this);
pd.setMessage("login");
pd.show();
}
@Override
protected String doInBackground(String... params) {
// List<NameValuePair> parms=new ArrayList<>();
for(urlString in params){
JSONObject json=jParser.makeHTTPRequest(urlString,"GET");
}
//rest is same
进行一些更改,看看是否有效:
new travel().execute(url);
您的任务:
class travel extends AsyncTask<String,Void,String>{
@Override
protected void onPreExecute() {
super.onPreExecute();
pd=new ProgressDialog(MainActivity.this);
pd.setMessage("login");
pd.show();
}
@Override
protected String doInBackground(String... params) {
// List<NameValuePair> parms=new ArrayList<>();
for(urlString in params){
JSONObject json=jParser.makeHTTPRequest(urlString,"GET");
}
//rest is same
1) 使用此代码更改JSONParser类中的代码。仅使用此代码
public JSONObject makeHTTPRequest(String urlString, String method) {
if(method.equals("POST")){
URL url = null;
try {
url = new URL(urlString);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setRequestProperty("Accept", "application/json");
BufferedReader br = new BufferedReader(new InputStreamReader(
(conn.getInputStream())));
String output;
StringBuilder sb = new StringBuilder();
while ((output = br.readLine()) != null) {
sb.append(output);
}
conn.disconnect();
json = sb.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (ProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}else if(method.equals("GET")){
URL url = null;
try {
url = new URL(urlString);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
conn.setRequestProperty("Accept", "application/json");
BufferedReader br = new BufferedReader(new InputStreamReader(
(conn.getInputStream())));
String output;
StringBuilder sb = new StringBuilder();
while ((output = br.readLine()) != null) {
sb.append(output);
}
conn.disconnect();
json = sb.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (ProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
e.printStackTrace();
}
return jObj;
}
2) 在MainActivity中,您必须在onCreate()方法中添加p=newArrayList();如下所示
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
P = new ArrayList<>();
new travel().execute();
}
@覆盖
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
P=新的ArrayList();
新行程().execute();
}
所有这些都完成了。它在我这边起作用。它肯定也会对你起作用。1)用这些代码更改JSONParser类中的代码。只使用这些虚构的代码
public JSONObject makeHTTPRequest(String urlString, String method) {
if(method.equals("POST")){
URL url = null;
try {
url = new URL(urlString);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setRequestProperty("Accept", "application/json");
BufferedReader br = new BufferedReader(new InputStreamReader(
(conn.getInputStream())));
String output;
StringBuilder sb = new StringBuilder();
while ((output = br.readLine()) != null) {
sb.append(output);
}
conn.disconnect();
json = sb.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (ProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}else if(method.equals("GET")){
URL url = null;
try {
url = new URL(urlString);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
conn.setRequestProperty("Accept", "application/json");
BufferedReader br = new BufferedReader(new InputStreamReader(
(conn.getInputStream())));
String output;
StringBuilder sb = new StringBuilder();
while ((output = br.readLine()) != null) {
sb.append(output);
}
conn.disconnect();
json = sb.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (ProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
e.printStackTrace();
}
return jObj;
}
2) 在MainActivity中,您必须在onCreate()方法中添加p=newArrayList();如下所示
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
P = new ArrayList<>();
new travel().execute();
}
@覆盖
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
P=新的ArrayList();
新行程().execute();
}
所有这些都完成了。它在我这边起作用了。它肯定也会对你起作用。logcat中的任何内容?你将json解析器类返回的对象存储在哪里?logcat中的任何内容?你将json解析器类返回的对象存储在哪里?我插入你的代码,但在第二行:p=jp.makeHTTPRequest(url,“GET”,parms);show me error.该错误表示其不兼容类型i插入更新的代码,但在我立即关闭应用程序时仍然可以粘贴您的LogCat报告吗?deltaspot.ir/log.txt不可访问。在您的问题中更新您的LogCat报告。是什么错误导致应用程序崩溃。我插入了您的代码,但在第二行:P=jp.makeHTTPRequest(url,“GET”,parms);show me error.the error say it compatible typei i insert your updated code但仍在运行应用程序时立即关闭能否粘贴LogCat报告?deltaspot.ir/log.txt不可访问。请在问题中更新LogCat报告。是什么错误导致应用程序崩溃。我更改了AsyncTask函数代码和JSONParser,但再次关闭了它当我启动应用程序时,你检查过NullPointerException来自何处吗?请提供你正在解析的json字符串。我找不到NullPointerException来自何处,但你可以在此链接中下载我的文件,并检查是否也提供你想要pars.h的json字符串这是我的json代码:我更改了AsyncTask函数代码和JSONParser,但在启动应用程序时再次关闭了它。您是否检查了NullPointerException来自何处?请给出您正在解析的json字符串。我找不到NullPointerException来自何处,但您可以在此链接和chec中下载我的文件ked也提供您想要解析的json字符串。以下是我的json代码: