我不确定我需要包含多少关于这个问题的信息。我在下面复制了我的 JSON 编码，但如果需要任何其他编码，我可以提供。此外，在出错时会提供 LogCat 错误日志。
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
refresh = (Button) findViewById(R.id.button1);
refresh.setOnClickListener(new View.OnClickListener()
{
public void onClick(View view)
{
String result = null;
InputStream is = null;
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.jamiepaleschi.co.uk/android_login/selectall.php");
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();
result=sb.toString();
}
catch(Exception e)
{
Log.e("log_tag", "Error converting result "+e.toString());
Toast.makeText(getApplicationContext(), " Input reading fail", Toast.LENGTH_SHORT).show();
}
//parse json data
try
{
JSONArray jArray = new JSONArray(result);
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(Main.this);
tr.setLayoutParams(new LayoutParams(
LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT));
if(flag==1)
{
TextView b1=new TextView(Main.this);
b1.setText("Mon");
b1.setTextColor(Color.BLUE);
b1.setTextSize(15);
tr.addView(b1);
TextView b19=new TextView(Main.this);
b19.setPadding(10, 0, 0, 0);
b19.setTextSize(15);
b19.setText("Tue");
b19.setTextColor(Color.BLUE);
tr.addView(b19);
TextView b29=new TextView(Main.this);
b29.setPadding(10, 0, 0, 0);
b29.setText("Wed");
b29.setTextColor(Color.BLUE);
b29.setTextSize(15);
tr.addView(b29);
TextView b39=new TextView(Main.this);
b39.setPadding(10, 0, 0, 0);
b39.setText("Thur");
b39.setTextColor(Color.BLUE);
b39.setTextSize(15);
tr.addView(b39);
TextView b49=new TextView(Main.this);
b49.setPadding(10, 0, 0, 0);
b49.setText("Fri");
b49.setTextColor(Color.BLUE);
b49.setTextSize(15);
tr.addView(b49);
tv.addView(tr);
final View vline = new View(Main.this);
vline.setLayoutParams(new TableRow.LayoutParams(TableRow.LayoutParams.WRAP_CONTENT, 2));
vline.setBackgroundColor(Color.BLUE);
tv.addView(vline);
flag=0;
}
else
{
JSONObject json_data = jArray.getJSONObject(i);
Log.i("log_tag","Mon: "+json_data.getString("f1")+
", Tue: "+json_data.getString("f2")+
", Wed: "+json_data.getString("f3")+
", Thur: "+json_data.getString("f4")+
", Fri: "+json_data.getString("f5"));
TextView b=new TextView(Main.this);
String stime=String.valueOf(json_data.getString("f1"));
b.setText(stime);
b.setTextColor(Color.RED);
b.setTextSize(10);
b.setWidth(60);
tr.addView(b);
TextView b1=new TextView(Main.this);
b1.setPadding(10, 0, 0, 0);
b1.setTextSize(10);
b1.setWidth(60);
String stime1=json_data.getString("f2");
b1.setText(stime1);
b1.setTextColor(Color.WHITE);
tr.addView(b1);
TextView b2=new TextView(Main.this);
b2.setPadding(10, 0, 0, 0);
String stime2=String.valueOf(json_data.getString("f3"));
b2.setText(stime2);
b2.setTextColor(Color.RED);
b2.setTextSize(10);
b2.setWidth(60);
tr.addView(b2);
TextView b3=new TextView(Main.this);
b3.setPadding(10, 0, 0, 0);
String stime3=String.valueOf(json_data.getString("f4"));
b3.setText(stime3);
b3.setTextColor(Color.WHITE);
b3.setTextSize(10);
b3.setWidth(60);
tr.addView(b3);
TextView b4=new TextView(Main.this);
b4.setPadding(10, 0, 0, 0);
String stime4=String.valueOf(json_data.getString("f5"));
b4.setText(stime4);
b4.setTextColor(Color.RED);
b4.setTextSize(10);
b4.setWidth(60);
tr.addView(b4);
tv.addView(tr);
final View vline1 = new View(Main.this);
vline1.setLayoutParams(new TableRow.LayoutParams(TableRow.LayoutParams.WRAP_CONTENT, 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();
}
}
});
/**
* Change Password Activity Started
**/
changepas.setOnClickListener(new View.OnClickListener(){
public void onClick(View arg0){
Intent chgpass = new Intent(getApplicationContext(), ChangePassword.class);
startActivity(chgpass);
}
});
/**
*Logout from the User Panel which clears the data in Sqlite database
**/
btnLogout.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
UserFunctions logout = new UserFunctions();
logout.logoutUser(getApplicationContext());
Intent login = new Intent(getApplicationContext(), Login.class);
login.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(login);
finish();
}
});
猫错误日志
03-04 04:03:13.509: W/dalvikvm(797): threadid=1: thread exiting with uncaught exception (group=0x414c4700)
03-04 04:03:13.530: E/AndroidRuntime(797): FATAL EXCEPTION: main
03-04 04:03:13.530: E/AndroidRuntime(797): java.lang.NullPointerException
03-04 04:03:13.530: E/AndroidRuntime(797): at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:116)
03-04 04:03:13.530: E/AndroidRuntime(797): at org.json.JSONTokener.nextValue(JSONTokener.java:94)
03-04 04:03:13.530: E/AndroidRuntime(797): at org.json.JSONArray.<init>(JSONArray.java:87)
03-04 04:03:13.530: E/AndroidRuntime(797): at org.json.JSONArray.<init>(JSONArray.java:103)
03-04 04:03:13.530: E/AndroidRuntime(797): at com.learn2crack.Main$1.onClick(Main.java:129)
03-04 04:03:13.530: E/AndroidRuntime(797): at android.view.View.performClick(View.java:4240)
03-04 04:03:13.530: E/AndroidRuntime(797): at android.view.View$PerformClick.run(View.java:17721)
03-04 04:03:13.530: E/AndroidRuntime(797): at android.os.Handler.handleCallback(Handler.java:730)
03-04 04:03:13.530: E/AndroidRuntime(797): at android.os.Handler.dispatchMessage(Handler.java:92)
03-04 04:03:13.530: E/AndroidRuntime(797): at android.os.Looper.loop(Looper.java:137)
03-04 04:03:13.530: E/AndroidRuntime(797): at android.app.ActivityThread.main(ActivityThread.java:5103)
03-04 04:03:13.530: E/AndroidRuntime(797): at java.lang.reflect.Method.invokeNative(Native Method)
03-04 04:03:13.530: E/AndroidRuntime(797): at java.lang.reflect.Method.invoke(Method.java:525)
03-04 04:03:13.530: E/AndroidRuntime(797): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
03-04 04:03:13.530: E/AndroidRuntime(797): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
03-04 04:03:13.530: E/AndroidRuntime(797): at dalvik.system.NativeStart.main(Native Method)
最新代码版本主.java
public class Main extends Activity{
Button btnLogout;
Button changepas;
Button refresh;
/**
* Called when the activity is first created.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
changepas = (Button) findViewById(R.id.btchangepass);
btnLogout = (Button) findViewById(R.id.logout);
refresh = (Button) findViewById(R.id.button1);
DatabaseHandler db = new DatabaseHandler(getApplicationContext());
/**
* Hashmap to load data from the Sqlite database
**/
HashMap<String,String> user = new HashMap<String, String>();
user = db.getUserDetails();
/**
* TimeTable Refresh
*/
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
refresh = (Button) findViewById(R.id.button1);
refresh.setOnClickListener(new View.OnClickListener()
{
public void onClick(View view)
{
String result = null;
InputStream is = null;
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.jamiepaleschi.co.uk/android_login/selectall.php");
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();
result=sb.toString();
}
catch(Exception e)
{
Log.e("log_tag", "Error converting result "+e.toString());
Toast.makeText(getApplicationContext(), " Input reading fail", Toast.LENGTH_SHORT).show();
}
//parse json data
try
{
JSONArray jArray = new JSONArray(result);
String re=jArray.getString(jArray.length());
TableLayout tv=(TableLayout) findViewById(R.id.table);
tv.removeAllViewsInLayout();
int flag=1;
for(int i=0;i<jArray.length();i++){
Object obj = jArray.get(i);
if (obj instanceof JSONObject) {
// is JSONObject
JSONObject json_data = (JSONObject)obj;
}else{
TableRow tr=new TableRow(Main.this);
tr.setLayoutParams(new LayoutParams(
LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT));
if(flag==1)
{
TextView b1=new TextView(Main.this);
b1.setText("Mon");
b1.setTextColor(Color.BLUE);
b1.setTextSize(15);
tr.addView(b1);
TextView b19=new TextView(Main.this);
b19.setPadding(10, 0, 0, 0);
b19.setTextSize(15);
b19.setText("Tue");
b19.setTextColor(Color.BLUE);
tr.addView(b19);
TextView b29=new TextView(Main.this);
b29.setPadding(10, 0, 0, 0);
b29.setText("Wed");
b29.setTextColor(Color.BLUE);
b29.setTextSize(15);
tr.addView(b29);
TextView b39=new TextView(Main.this);
b39.setPadding(10, 0, 0, 0);
b39.setText("Thur");
b39.setTextColor(Color.BLUE);
b39.setTextSize(15);
tr.addView(b39);
TextView b49=new TextView(Main.this);
b49.setPadding(10, 0, 0, 0);
b49.setText("Fri");
b49.setTextColor(Color.BLUE);
b49.setTextSize(15);
tr.addView(b49);
tv.addView(tr);
final View vline = new View(Main.this);
vline.setLayoutParams(new TableRow.LayoutParams(TableRow.LayoutParams.WRAP_CONTENT, 2));
vline.setBackgroundColor(Color.BLUE);
tv.addView(vline);
flag=0;
}
else
{
JSONObject json_data = jArray.getJSONObject(i);
Log.i("log_tag","Mon: "+json_data.getString("f1")+
", Tue: "+json_data.getString("f2")+
", Wed: "+json_data.getString("f3")+
", Thur: "+json_data.getString("f4")+
", Fri: "+json_data.getString("f5"));
TextView b=new TextView(Main.this);
String stime=String.valueOf(json_data.getString("f1"));
b.setText(stime);
b.setTextColor(Color.RED);
b.setTextSize(10);
b.setWidth(60);
tr.addView(b);
TextView b1=new TextView(Main.this);
b1.setPadding(10, 0, 0, 0);
b1.setTextSize(10);
b1.setWidth(60);
String stime1=json_data.getString("f2");
b1.setText(stime1);
b1.setTextColor(Color.WHITE);
tr.addView(b1);
TextView b2=new TextView(Main.this);
b2.setPadding(10, 0, 0, 0);
String stime2=String.valueOf(json_data.getString("f3"));
b2.setText(stime2);
b2.setTextColor(Color.RED);
b2.setTextSize(10);
b2.setWidth(60);
tr.addView(b2);
TextView b3=new TextView(Main.this);
b3.setPadding(10, 0, 0, 0);
String stime3=String.valueOf(json_data.getString("f4"));
b3.setText(stime3);
b3.setTextColor(Color.WHITE);
b3.setTextSize(10);
b3.setWidth(60);
tr.addView(b3);
TextView b4=new TextView(Main.this);
b4.setPadding(10, 0, 0, 0);
String stime4=String.valueOf(json_data.getString("f5"));
b4.setText(stime4);
b4.setTextColor(Color.RED);
b4.setTextSize(10);
b4.setWidth(60);
tr.addView(b4);
tv.addView(tr);
final View vline1 = new View(Main.this);
vline1.setLayoutParams(new TableRow.LayoutParams(TableRow.LayoutParams.WRAP_CONTENT, 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();
}
}
});
日志猫错误
03-04 05:04:58.727: E/AndroidRuntime(1005): FATAL EXCEPTION: main
03-04 05:04:58.727: E/AndroidRuntime(1005): java.lang.NullPointerException
03-04 05:04:58.727: E/AndroidRuntime(1005): at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:116)
03-04 05:04:58.727: E/AndroidRuntime(1005): at org.json.JSONTokener.nextValue(JSONTokener.java:94)
03-04 05:04:58.727: E/AndroidRuntime(1005): at org.json.JSONArray.<init>(JSONArray.java:87)
03-04 05:04:58.727: E/AndroidRuntime(1005): at org.json.JSONArray.<init>(JSONArray.java:103)
03-04 05:04:58.727: E/AndroidRuntime(1005): at com.learn2crack.Main$1.onClick(Main.java:129)
03-04 05:04:58.727: E/AndroidRuntime(1005): at android.view.View.performClick(View.java:4240)
03-04 05:04:58.727: E/AndroidRuntime(1005): at android.view.View$PerformClick.run(View.java:17721)
03-04 05:04:58.727: E/AndroidRuntime(1005): at android.os.Handler.handleCallback(Handler.java:730)
03-04 05:04:58.727: E/AndroidRuntime(1005): at android.os.Handler.dispatchMessage(Handler.java:92)
03-04 05:04:58.727: E/AndroidRuntime(1005): at android.os.Looper.loop(Looper.java:137)
03-04 05:04:58.727: E/AndroidRuntime(1005): at android.app.ActivityThread.main(ActivityThread.java:5103)
03-04 05:04:58.727: E/AndroidRuntime(1005): at java.lang.reflect.Method.invokeNative(Native Method)
03-04 05:04:58.727: E/AndroidRuntime(1005): at java.lang.reflect.Method.invoke(Method.java:525)
03-04 05:04:58.727: E/AndroidRuntime(1005): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
03-04 05:04:58.727: E/AndroidRuntime(1005): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
03-04 05:04:58.727: E/AndroidRuntime(1005): at dalvik.system.NativeStart.main(Native Method)
这里 ：
JSONObject json_data = jArray.getJSONObject(i);
当i==-1时，则getJSONObject返回 null，因为对象在索引-1中不可用 JSONArray.so 更改迭代条件为：
for(int i=0;i<jArray.length();i++){
Object obj = jArray.get(i);
if (obj instanceof JSONObject) {
// is JSONObject
JSONObject json_data = (JSONObject)obj;
}else{
//String....
}
}
更改以下行。如果 json 结果为 null，它们将引发 Null 指针异常。
String re=jArray.getString(jArray.length()-1);
自
String re= null;
if(jArray.length!=0)jArray.getString(jArray.length()-1);
和
for(int i=-1;i<jArray.length()-1;i++)
自
for(int i=0;i<jArray.length();i++)