我对这个编程很新，并试图做几件事。我尝试了这里提供的示例代码。我不知道我错在哪里。我想将json存储到sqlite db中，但它显示错误。请告诉我解决方案。提前致谢。
我的Json文件格式如下：
[{"Companies":"Agriculture Development Bank","Tran.":"94","Max.":"484","Min.":"469","Close":"480","Volume":"13779","Amount":"6598289","Last Close":"478","Net Chg":"[TABLE]","":"","id":0},{"Companies":"Alliance Insurance Co. Ltd.","Tran.":"2","Max.":"550","Min.":"539","Close":"539","Volume":"750","Amount":"407000","Last Close":"550","Net Chg":"[TABLE]","":"","id":1}]
我的loginactivity.java文件是这样的
package com.example.merostock;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.annotation.TargetApi;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.annotation.TargetApi;
import android.widget.TextView;
public class LoginActivity extends Activity {
DBAdapter myDb;
private ProgressDialog pDialog;
// URL to get contacts JSON
private static String url = "http://www.dreamsint.com.np/nepse.json.php";
// JSON Node names
private static final String TAG_COMPANIES = "Companies";
private static final String TAG_TRAN = "Tran.";
private static final String TAG_MAX = "Max.";
private static final String TAG_MIN = "Min.";
private static final String TAG_CLOSE = "Close";
private static final String TAG_VOLUME = "Volume";
private static final String TAG_AMOUNT = "Amount";
private static final String TAG_LASTCLOSE = "Last Close";
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// setting default screen to login.xml
setContentView(R.layout.login);
//openDB();
myDb = new DBAdapter(this);
myDb.open();
TextView registerScreen = (TextView) findViewById(R.id.link_to_register);
// Listening to register new account link
registerScreen.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Switching to Register screen
Intent i = new Intent(getApplicationContext(), RegisterActivity.class);
startActivity(i);
}
});
new GetContacts().execute();
}
protected void onDestroy() {
super.onDestroy();
closeDB();
}
private void openDB() {
myDb = new DBAdapter(this);
myDb.open();
}
private void closeDB() {
myDb.close();
}
private class GetContacts extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(LoginActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@TargetApi(19)
@Override
protected Void doInBackground(Void... arg0) {
// Creating JSON Parser instance
JSONArray arr = null;
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
try {
// Getting Array of Contacts
arr = new JSONArray(json);
//contacts = json.getJSONArray(TAG_CONTACTS);
// looping through All Contacts
for (int i = 0; i < arr.length(); i++) {
JSONObject c = arr.getJSONObject(i);
// Storing each json item in variable
String companies = c.getString(TAG_COMPANIES);
String tran = c.getString(TAG_TRAN);
String max = c.getString(TAG_MAX);
String min = c.getString(TAG_MIN);
String close = c.getString(TAG_CLOSE);
String volume = c.getString(TAG_VOLUME);
String amt = c.getString(TAG_AMOUNT);
String lastclose = c.getString(TAG_LASTCLOSE);
myDb.insertRow(companies, tran, max, min, close, volume, amt, lastclose);
}
}catch (JSONException e) {
e.printStackTrace();
}
return null;
}}
}
我的DBAdapter.java文件
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DBAdapter {
/////////////////////////////////////////////////////////////////////
// Constants & Data
/////////////////////////////////////////////////////////////////////
// For logging:
private static final String TAG = "DBAdapter";
// DB Fields
public static final String KEY_ROWID = "id";
public static final int COL_ROWID = 0;
/*
* CHANGE 1:
*/
// TODO: Setup your fields here:
public static final String KEY_COMPANIES = "companies";
public static final String KEY_TRANSACTIONS = "transactions";
public static final String KEY_MAX = "max";
public static final String KEY_MIN = "min";
public static final String KEY_CLOSE = "close";
public static final String KEY_VOLUME = "volume";
public static final String KEY_AMOUNT = "amt";
public static final String KEY_LASTCLOSE = "lastclose";
// TODO: Setup your field numbers here (0 = KEY_ROWID, 1=...)
public static final int COL_NAME = 1;
public static final int COL_STUDENTNUM = 2;
public static final int COL_FAVCOLOUR = 3;
public static final String[] ALL_KEYS = new String[] {KEY_ROWID, KEY_COMPANIES, KEY_TRANSACTIONS, KEY_MAX, KEY_MIN, KEY_CLOSE, KEY_VOLUME, KEY_AMOUNT, KEY_LASTCLOSE};
// DB info: it's name, and the table we are using (just one).
public static final String DATABASE_NAME = "MyDb.db";
public static final String DATABASE_TABLE = "mainTable";
// Track DB version if a new version of your app changes the format.
public static final int DATABASE_VERSION = 2;
private static final String DATABASE_CREATE_SQL =
"create table " + DATABASE_TABLE
+ " (" + KEY_ROWID + " integer primary key autoincrement, "
/*
* CHANGE 2:
*/
// TODO: Place your fields here!
// + KEY_{...} + " {type} not null"
// - Key is the column name you created above.
// - {type} is one of: text, integer, real, blob
// (http://www.sqlite.org/datatype3.html)
// - "not null" means it is a required field (must be given a value).
// NOTE: All must be comma separated (end of line!) Last one must have NO comma!!
+ KEY_COMPANIES + " text not null, "
+ KEY_TRANSACTIONS + " text not null, "
+ KEY_MAX + " text not null, "
+ KEY_MIN + " text not null, "
+ KEY_CLOSE + " text not null, "
+ KEY_VOLUME + " text not null, "
+ KEY_AMOUNT + " text not null, "
+ KEY_LASTCLOSE + "text not null "
// Rest of creation:
+ ");";
// Context of application who uses us.
private final Context context;
private DatabaseHelper myDBHelper;
private SQLiteDatabase db;
/////////////////////////////////////////////////////////////////////
// Public methods:
/////////////////////////////////////////////////////////////////////
public DBAdapter(Context ctx) {
this.context = ctx;
myDBHelper = new DatabaseHelper(context);
}
// Open the database connection.
public DBAdapter open() {
db = myDBHelper.getWritableDatabase();
return this;
}
// Close the database connection.
public void close() {
myDBHelper.close();
}
// Add a new set of values to the database.
public long insertRow(String companies, String tran, String max, String min, String close, String volume, String amt, String lastclose ) {
/*
* CHANGE 3:
*/
// TODO: Update data in the row with new fields.
// TODO: Also change the function's arguments to be what you need!
// Create row's data:
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_COMPANIES, companies);
initialValues.put(KEY_TRANSACTIONS, tran);
initialValues.put(KEY_MAX, max);
initialValues.put(KEY_MIN, min);
initialValues.put(KEY_CLOSE, close);
initialValues.put(KEY_VOLUME, volume);
initialValues.put(KEY_AMOUNT, amt);
initialValues.put(KEY_LASTCLOSE, lastclose);
// Insert it into the database.
return db.insert(DATABASE_TABLE, null, initialValues);
}
// Delete a row from the database, by rowId (primary key)
public boolean deleteRow(long rowId) {
String where = KEY_ROWID + "=" + rowId;
return db.delete(DATABASE_TABLE, where, null) != 0;
}
public void deleteAll() {
Cursor c = getAllRows();
long rowId = c.getColumnIndexOrThrow(KEY_ROWID);
if (c.moveToFirst()) {
do {
deleteRow(c.getLong((int) rowId));
} while (c.moveToNext());
}
c.close();
}
// Return all data in the database.
public Cursor getAllRows() {
String where = null;
Cursor c = db.query(true, DATABASE_TABLE, ALL_KEYS,
where, null, null, null, null, null);
if (c != null) {
c.moveToFirst();
}
return c;
}
// Get a specific row (by rowId)
public Cursor getRow(long rowId) {
String where = KEY_ROWID + "=" + rowId;
Cursor c = db.query(true, DATABASE_TABLE, ALL_KEYS,
where, null, null, null, null, null);
if (c != null) {
c.moveToFirst();
}
return c;
}
// Change an existing row to be equal to new data.
public boolean updateRow(long rowId, String name, int studentNum, String favColour) {
String where = KEY_ROWID + "=" + rowId;
/*
* CHANGE 4:
*/
// TODO: Update data in the row with new fields.
// TODO: Also change the function's arguments to be what you need!
// Create row's data:
ContentValues newValues = new ContentValues();
newValues.put(KEY_COMPANIES, name);
newValues.put(KEY_TRANSACTIONS, studentNum);
newValues.put(KEY_MAX, favColour);
// Insert it into the database.
return db.update(DATABASE_TABLE, newValues, where, null) != 0;
}
/////////////////////////////////////////////////////////////////////
// Private Helper Classes:
/////////////////////////////////////////////////////////////////////
/**
* Private class which handles database creation and upgrading.
* Used to handle low-level database access.
*/
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase _db) {
_db.execSQL(DATABASE_CREATE_SQL);
}
@Override
public void onUpgrade(SQLiteDatabase _db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading application's database from version " + oldVersion
+ " to " + newVersion + ", which will destroy all old data!");
// Destroy old database:
_db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
// Recreate new database:
onCreate(_db);
}
}
}
我的JSONParser.java文件
package com.example.merostock;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
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");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
Logcat
01-25 07:05:35.849: E/JSON Parser(1483): Error parsing data org.json.JSONException: Value [{"id":0,"":"","--":"--","#VALUE!":"--"},{"id":1,"":"","--":"--","#VALUE!":"--"},{"id":2,"":"","--":"--","#VALUE!":"--"},{"id":3,"":"","--":"--","#VALUE!":"--"},{"id":4,"":"","--":"--","#VALUE!":"--"},{"id":5,"":"","--":"--","#VALUE!":"--"},{"id":6,"":"","--":"--","#VALUE!":"--"},{"id":7,"":"","--":"--","#VALUE!":"--"},{"id":8,"":"","--":"--","#VALUE!":"--"},{"id":9,"":"1\/25\/2014 17:50:00","--":"--","#VALUE!":"--"},{"id":10,"":"","--":"--
01-25 07:05:35.849: W/dalvikvm(1483): threadid=11: thread exiting with uncaught exception (group=0xb3af5ba8)
01-25 07:05:35.889: I/Choreographer(1483): Skipped 36 frames! The application may be doing too much work on its main thread.
01-25 07:05:36.549: E/AndroidRuntime(1483): FATAL EXCEPTION: AsyncTask #1
01-25 07:05:36.549: E/AndroidRuntime(1483): Process: com.example.merostock, PID: 1483
01-25 07:05:36.549: E/AndroidRuntime(1483): java.lang.RuntimeException: An error occured while executing doInBackground()
01-25 07:05:36.549: E/AndroidRuntime(1483): at android.os.AsyncTask$3.done(AsyncTask.java:300)
01-25 07:05:36.549: E/AndroidRuntime(1483): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
01-25 07:05:36.549: E/AndroidRuntime(1483): at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
01-25 07:05:36.549: E/AndroidRuntime(1483): at java.util.concurrent.FutureTask.run(FutureTask.java:242)
01-25 07:05:36.549: E/AndroidRuntime(1483): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
01-25 07:05:36.549: E/AndroidRuntime(1483): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
01-25 07:05:36.549: E/AndroidRuntime(1483): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
01-25 07:05:36.549: E/AndroidRuntime(1483): at java.lang.Thread.run(Thread.java:841)
01-25 07:05:36.549: E/AndroidRuntime(1483): Caused by: java.lang.NullPointerException
01-25 07:05:36.549: E/AndroidRuntime(1483): at org.json.JSONArray.<init>(JSONArray.java:115)
01-25 07:05:36.549: E/AndroidRuntime(1483): at com.example.merostock.LoginActivity$GetContacts.doInBackground(LoginActivity.java:96)
01-25 07:05:36.549: E/AndroidRuntime(1483): at com.example.merostock.LoginActivity$GetContacts.doInBackground(LoginActivity.java:1)
01-25 07:05:36.549: E/AndroidRuntime(1483): at android.os.AsyncTask$2.call(AsyncTask.java:288)
01-25 07:05:36.549: E/AndroidRuntime(1483): at java.util.concurrent.FutureTask.run(FutureTask.java:237)
01-25 07:05:36.549: E/AndroidRuntime(1483): ... 4 more
01-25 07:05:36.819: I/Choreographer(1483): Skipped 63 frames! The application may be doing too much work on its main thread.
01-25 07:05:37.179: I/Choreographer(1483): Skipped 92 frames! The application may be doing too much work on its main thread.
01-25 07:05:37.439: I/Choreographer(1483): Skipped 67 frames! The application may be doing too much work on its main thread.
01-25 07:05:37.649: I/Choreographer(1483): Skipped 49 frames! The application may be doing too much work on its main thread.
01-25 07:05:37.919: I/Choreographer(1483): Skipped 67 frames! The application may be doing too much work on its main thread.
01-25 07:05:39.499: I/Choreographer(1483): Skipped 39 frames! The application may be doing too much work on its main thread.
01-25 07:05:39.639: I/Choreographer(1483): Skipped 34 frames! The application may be doing too much work on its main thread.
01-25 07:05:39.929: I/Choreographer(1483): Skipped 47 frames! The application may be doing too much work on its main thread.
01-25 07:05:40.269: I/Choreographer(1483): Skipped 53 frames! The application may be doing too much work on its main thread.
01-25 07:05:40.519: I/Choreographer(1483): Skipped 30 frames! The application may be doing too much work on its main thread.
01-25 07:05:40.709: I/Choreographer(1483): Skipped 44 frames! The application may be doing too much work on its main thread.
01-25 07:05:42.419: E/WindowManager(1483): android.view.WindowLeaked: Activity com.example.merostock.LoginActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{b3eb3888 V.E..... R.....ID 0,0-456,144} that was originally added here
01-25 07:05:42.419: E/WindowManager(1483): at android.view.ViewRootImpl.<init>(ViewRootImpl.java:348)
01-25 07:05:42.419: E/WindowManager(1483): at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:248)
01-25 07:05:42.419: E/WindowManager(1483): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
01-25 07:05:42.419: E/WindowManager(1483): at android.app.Dialog.show(Dialog.java:286)
01-25 07:05:42.419: E/WindowManager(1483): at com.example.merostock.LoginActivity$GetContacts.onPreExecute(LoginActivity.java:80)
01-25 07:05:42.419: E/WindowManager(1483): at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:587)
01-25 07:05:42.419: E/WindowManager(1483): at android.os.AsyncTask.execute(AsyncTask.java:535)
01-25 07:05:42.419: E/WindowManager(1483): at com.example.merostock.LoginActivity.onCreate(LoginActivity.java:56)
01-25 07:05:42.419: E/WindowManager(1483): at android.app.Activity.performCreate(Activity.java:5231)
01-25 07:05:42.419: E/WindowManager(1483): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
01-25 07:05:42.419: E/WindowManager(1483): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
01-25 07:05:42.419: E/WindowManager(1483): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
01-25 07:05:42.419: E/WindowManager(1483): at android.app.ActivityThread.access$800(ActivityThread.java:135)
01-25 07:05:42.419: E/WindowManager(1483): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
01-25 07:05:42.419: E/WindowManager(1483): at android.os.Handler.dispatchMessage(Handler.java:102)
01-25 07:05:42.419: E/WindowManager(1483): at android.os.Looper.loop(Looper.java:136)
01-25 07:05:42.419: E/WindowManager(1483): at android.app.ActivityThread.main(ActivityThread.java:5017)
01-25 07:05:42.419: E/WindowManager(1483): at java.lang.reflect.Method.invokeNative(Native Method)
01-25 07:05:42.419: E/WindowManager(1483): at java.lang.reflect.Method.invoke(Method.java:515)
01-25 07:05:42.419: E/WindowManager(1483): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
01-25 07:05:42.419: E/WindowManager(1483): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
01-25 07:05:42.419: E/WindowManager(1483): at dalvik.system.NativeStart.main(Native Method)
01-25 07:10:36.829: I/Process(1483): Sending signal. PID: 1483 SIG: 9