我正在开发一个 android 应用程序和 c# 桌面应用程序。我的 c# 应用程序正在连接 sql server 数据库。我正在使用 JSON c# Web 服务从数据库中读取/发送 android 中的数据。
我正在使用代码从数据库中检索数据并将其显示在表中的 android 中。这是安卓代码：
public class StudentActivity extends Activity
{
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.student);
Button button2 = (Button) findViewById(R.id.button2);
button2.setOnClickListener(new View.OnClickListener()
{
public void onClick(View view)
{
String rs = null;
InputStream is = null;
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://10.0.2.2:51220/Service1.svc/getData?");
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
Log.e("log_tag", "connection success ");
// Toast.makeText(getApplicationContext(), "pass", Toast.LENGTH_SHORT).show();
}
catch(Exception e)
{
Log.e("log_tag", "Error in http connection "+e.toString());
Toast.makeText(getApplicationContext(), "Connection fail", Toast.LENGTH_SHORT).show();
}
//convert response to string
try
{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null)
{
sb.append(line + "\n");
// Toast.makeText(getApplicationContext(), "Input Reading pass", Toast.LENGTH_SHORT).show();
}
is.close();
rs=sb.toString();
}
catch(Exception e)
{
Log.e("log_tag", "Error converting rs "+e.toString());
Toast.makeText(getApplicationContext(), " Input reading fail", Toast.LENGTH_SHORT).show();
}
//parse json data
try
{
JSONArray jArray = new JSONArray(rs);
String re=jArray.getString(jArray.length()-1);
TableLayout tv=(TableLayout) findViewById(R.id.table);
tv.removeAllViewsInLayout();
int flag=1;
for(int i=-1;i<jArray.length()-1;i++)
{
TableRow tr=new TableRow(StudentActivity.this);
tr.setLayoutParams(new LayoutParams(
LayoutParams.FILL_PARENT,
LayoutParams.WRAP_CONTENT));
if(flag==1)
{
TextView b6=new TextView(StudentActivity.this);
b6.setText("ID");
b6.setTextColor(Color.BLUE);
b6.setTextSize(15);
tr.addView(b6);
TextView b19=new TextView(StudentActivity.this);
b19.setPadding(10, 0, 0, 0);
b19.setTextSize(15);
b19.setText("First Name");
b19.setTextColor(Color.BLUE);
tr.addView(b19);
TextView b29=new TextView(StudentActivity.this);
b29.setPadding(10, 0, 0, 0);
b29.setText("Last Name");
b29.setTextColor(Color.BLUE);
b29.setTextSize(15);
tr.addView(b29);
TextView b4=new TextView(StudentActivity.this);
b4.setPadding(10, 0, 0, 0);
b4.setText("Project");
b4.setTextColor(Color.BLUE);
b4.setTextSize(15);
tr.addView(b4);
TextView b5=new TextView(StudentActivity.this);
b5.setPadding(10, 0, 0, 0);
b5.setText("Date and Time");
b5.setTextColor(Color.BLUE);
b5.setTextSize(15);
tr.addView(b5);
tv.addView(tr);
final View vline = new View(StudentActivity.this);
vline.setLayoutParams(new TableRow.LayoutParams(TableRow.LayoutParams.FILL_PARENT, 2));
vline.setBackgroundColor(Color.BLUE);
tv.addView(vline);
flag=0;
}
else
{
JSONObject json_data = jArray.getJSONObject(i);
Log.i("log_tag","id: "+json_data.getInt("f1")+
", firstname: "+json_data.getString("f2")+
", lastname: "+json_data.getInt("f3") +
", project: "+json_data.getString("f4")+
", datetime: "+json_data.getString("f5"));
TextView b=new TextView(StudentActivity.this);
String stime=String.valueOf(json_data.getInt("f1"));
b.setText(stime);
b.setTextColor(Color.RED);
b.setTextSize(15);
tr.addView(b);
TextView b1=new TextView(StudentActivity.this);
b1.setPadding(10, 0, 0, 0);
b1.setTextSize(15);
String stime1=json_data.getString("f2");
b1.setText(stime1);
b1.setTextColor(Color.WHITE);
tr.addView(b1);
TextView b2=new TextView(StudentActivity.this);
b2.setPadding(10, 0, 0, 0);
String stime2=String.valueOf(json_data.getInt("f3"));
b2.setText(stime2);
b2.setTextColor(Color.RED);
b2.setTextSize(15);
tr.addView(b2);
TextView b3=new TextView(StudentActivity.this);
b3.setPadding(10, 0, 0, 0);
String stime3=String.valueOf(json_data.getInt("f4"));
b3.setText(stime3);
b3.setTextColor(Color.WHITE);
b3.setTextSize(15);
tr.addView(b3);
TextView b4=new TextView(StudentActivity.this);
b4.setPadding(10, 0, 0, 0);
String stime4=String.valueOf(json_data.getInt("f5"));
b4.setText(stime4);
b4.setTextColor(Color.RED);
b4.setTextSize(15);
tr.addView(b4);
tv.addView(tr);
final View vline1 = new View(StudentActivity.this);
vline1.setLayoutParams(new TableRow.LayoutParams(TableRow.LayoutParams.FILL_PARENT, 1));
vline1.setBackgroundColor(Color.WHITE);
tv.addView(vline1);
}
}
}
catch(JSONException e)
{
Log.e("log_tag", "Error parsing data "+e.toString());
Toast.makeText(getApplicationContext(), "JsonArray fail", Toast.LENGTH_SHORT).show();
}
}
});
}
}
当我单击按钮从数据库中检索数据时运行时，我的应用程序正在捕获此异常
catch(JSONException e)
{
Log.e("log_tag", "Error parsing data "+e.toString());
Toast.makeText(getApplicationContext(), "JsonArray fail", Toast.LENGTH_SHORT).show();
}
我不明白为什么它会捕获此异常并显示“JsonArray 失败”，因为这是一个示例代码，我刚刚开始学习 JSON Web 服务。请帮我解决它。如果您想了解更多信息，请告诉我我会为您提供。谢谢