sqlite錯誤打開跟蹤文件

Question

我是一個noob，當涉及到android編程，我有特別的麻煩讓我的頭周圍的SQLite。當我運行我的應用程序時，它加載正常，但出現錯誤「打開跟蹤文件的錯誤：沒有這樣的文件或目錄（2）」。然後，當我點擊我的按鈕，應該插入串真棒到我的數據庫，然後在TextView的這些錯誤來和應用程序崩潰返回它：

03-15 17:35:01.523: E/Trace(794): error opening trace file: No such file or directory (2) 
03-15 17:35:02.223: D/gralloc_goldfish(794): Emulator without GPU emulation detected. 
03-15 17:37:48.623: E/SQLiteLog(794): (1) no such column: _id 
03-15 17:37:48.623: D/AndroidRuntime(794): Shutting down VM 
03-15 17:37:48.623: W/dalvikvm(794): threadid=1: thread exiting with uncaught exception (group=0x40a13300) 
03-15 17:37:48.673: E/AndroidRuntime(794): FATAL EXCEPTION: main 
03-15 17:37:48.673: E/AndroidRuntime(794): java.lang.IllegalStateException: Could not execute method of the activity 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.view.View$1.onClick(View.java:3591) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.view.View.performClick(View.java:4084) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.view.View$PerformClick.run(View.java:16966) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.os.Handler.handleCallback(Handler.java:615) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.os.Handler.dispatchMessage(Handler.java:92) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.os.Looper.loop(Looper.java:137) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.app.ActivityThread.main(ActivityThread.java:4745) 
03-15 17:37:48.673: E/AndroidRuntime(794): at java.lang.reflect.Method.invokeNative(Native Method) 
03-15 17:37:48.673: E/AndroidRuntime(794): at java.lang.reflect.Method.invoke(Method.java:511) 
03-15 17:37:48.673: E/AndroidRuntime(794): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
03-15 17:37:48.673: E/AndroidRuntime(794): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
03-15 17:37:48.673: E/AndroidRuntime(794): at dalvik.system.NativeStart.main(Native Method) 
03-15 17:37:48.673: E/AndroidRuntime(794): Caused by: java.lang.reflect.InvocationTargetException 
03-15 17:37:48.673: E/AndroidRuntime(794): at java.lang.reflect.Method.invokeNative(Native Method) 
03-15 17:37:48.673: E/AndroidRuntime(794): at java.lang.reflect.Method.invoke(Method.java:511) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.view.View$1.onClick(View.java:3586) 
03-15 17:37:48.673: E/AndroidRuntime(794): ... 11 more 
03-15 17:37:48.673: E/AndroidRuntime(794): Caused by: android.database.sqlite.SQLiteException: no such column: _id (code 1): , while compiling: SELECT _id, content FROM exampletable WHERE _id = 4 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:882) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:493) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1314) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1161) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1032) 
03-15 17:37:48.673: E/AndroidRuntime(794): at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1238) 
03-15 17:37:48.673: E/AndroidRuntime(794): at com.example.sqlite.MainActivity.insertButton(MainActivity.java:38) 
03-15 17:37:48.673: E/AndroidRuntime(794): ... 14 more 

我MainActivity.java：

package com.example.sqlite; 

import android.app.Activity; 
import android.content.ContentValues; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.os.Bundle; 
import android.view.Menu; 
import android.view.View; 
import android.widget.TextView; 

public class MainActivity extends Activity { 

    DBHelper dbhelper = new DBHelper(this); 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.main, menu); 
     return true; 
    } 

    public void insertButton(View view){ 
     SQLiteDatabase db = dbhelper.getWritableDatabase(); 
     ContentValues values = new ContentValues(); 
     values.put("content", "Awesome"); 

     long newRowId = db.insert("exampletable", null, values); 

     String[] projection = {"_id", "content"}; 

     Cursor c = db.query("exampletable", projection, "_id = " + newRowId, null, null, null, null, null); 

     c.moveToFirst(); 

     String content = c.getString(c.getColumnIndex("content")); 

     TextView textView = (TextView) findViewById(R.id.textView1); 
     textView.setText(content); 

    } 

} 

我的DBHelper.java：

package com.example.sqlite; 

import android.content.Context; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteOpenHelper; 

public class DBHelper extends SQLiteOpenHelper { 

    public static final int DATABASE_VERSION = 1; 
    public static final String DATABASE_NAME = "ExampleDB"; 

    private String ONCREATE_SQL = "CREATE TABLE exampletable(_id INTEGER PRIMARY KEY AUTOINCREMENT, content TEXT);"; 

    public DBHelper(Context context) { 
     super(context, DATABASE_NAME, null, DATABASE_VERSION); 
    } 

    @Override 
    public void onCreate(SQLiteDatabase db) { 
     db.execSQL(ONCREATE_SQL); 


    } 

    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 

    } 

} 

我在做什麼錯？並且是由於初始錯誤而點擊按鈕時出現的錯誤還是它們是分開的？非常感謝。

Answer 1

SQL語句無法執行，因爲數據庫中沒有列「_id」。 您是否嘗試重新創建表格？

確保表格被正確創建：

只是增加你的DATABASE_VERSION並實現onUpgrade方法：

@Override 
public void onUpgrade(SQLiteDatabase database) { 
    database.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME); 
    onCreate(database); 
} 

然後檢查日誌，如果有任何的錯誤，同時創建databasse表。 如果沒有，請查看/data/data/packename以查找您的SQLite數據庫; pull它在DDMS透視圖和check如果表已成功創建。