尝试列出数据库条目时应用程序崩溃

Question

在手机上重新安装应用程序之前，一切都很顺利。如有必要，我可以发布我的代码。我不知道是什么导致了这个问题。 这里是logcat的：

04-19 19:31:48.799: E/AndroidRuntime(24963): FATAL EXCEPTION: main 
04-19 19:31:48.799: E/AndroidRuntime(24963): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.classorganizer/com.example.classorganizer.Monday}: android.database.sqlite.SQLiteException: no such table: diaries: , while compiling: SELECT * FROM diaries 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.os.Handler.dispatchMessage(Handler.java:99) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.os.Looper.loop(Looper.java:130) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.app.ActivityThread.main(ActivityThread.java:3687) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at java.lang.reflect.Method.invokeNative(Native Method) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at java.lang.reflect.Method.invoke(Method.java:507) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at dalvik.system.NativeStart.main(Native Method) 
04-19 19:31:48.799: E/AndroidRuntime(24963): Caused by: android.database.sqlite.SQLiteException: no such table: diaries: , while compiling: SELECT * FROM diaries 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.database.sqlite.SQLiteCompiledSql.native_compile(Native Method) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.database.sqlite.SQLiteCompiledSql.compile(SQLiteCompiledSql.java:92) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.database.sqlite.SQLiteCompiledSql.<init>(SQLiteCompiledSql.java:65) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:83) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:49) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:42) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1501) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1380) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1334) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1416) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at com.cookbook.data.MyDB.getdiaries(MyDB.java:66) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at com.example.classorganizer.Monday$DiaryAdapter.getdata(Monday.java:86) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at com.example.classorganizer.Monday$DiaryAdapter.<init>(Monday.java:80) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at com.example.classorganizer.Monday.onCreate(Monday.java:68) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
04-19 19:31:48.799: E/AndroidRuntime(24963): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615) 
04-19 19:31:48.799: E/AndroidRuntime(24963): ... 11 more 

这里是我的MyDBhelper文件：

package com.cookbook.data; 





import android.content.ContentValues; 
import android.content.Context; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteDatabase.CursorFactory; 
import android.database.sqlite.SQLiteException; 
import android.database.sqlite.SQLiteOpenHelper; 
import android.util.Log; 


public class MyDBhelper extends SQLiteOpenHelper{ 


private static final String CREATE_TABLE="create table "+ 
Constants.TABLE_NAME+" ("+ 
Constants.KEY_ID+" integer primary key autoincrement, "+ 
Constants.TITLE_NAME+" text not null, "+ 
Constants.CONTENT_NAME+" text not null, " 
; 
private SQLiteDatabase db; 



// database initialization 
public MyDBhelper(Context context, String name, CursorFactory factory, 
        int version) { 
    super(context, name, factory, version); 

} 



@Override 
public void onCreate(SQLiteDatabase db) { 
    Log.v("MyDBhelper onCreate","Creating all the tables"); 



    try { 
     this.db = db; 
     db.execSQL(CREATE_TABLE); 

     for(int i=1; i <= 48; i++) { insertdiary(db, "free",""); } 

    } 

    catch(SQLiteException ex) { 
     Log.v("Create table exception", ex.getMessage()); 

    } 

} 


// Saves a diary entry to the database as name-value pairs in ContentValues instance 
      // then passes the data to the SQLitedatabase instance to do an insert 
      public long insertdiary(SQLiteDatabase db, String title, String content) 
      { 


       try{ 
        ContentValues newTaskValue = new ContentValues(); 
        newTaskValue.put(Constants.TITLE_NAME, title); 
        newTaskValue.put(Constants.CONTENT_NAME, content); 

        return db.insert(Constants.TABLE_NAME, null, newTaskValue); 

       } catch(SQLiteException ex) { 
        Log.v("Insert into database exception caught", 
          ex.getMessage()); 
        return -1; 
       } 

      } 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, 
         int newVersion) { 
    Log.w("TaskDBAdapter", "Upgrading from version "+oldVersion 
          +" to "+newVersion 
          +", which will destroy all old data"); 
    db.execSQL("drop table if exists "+Constants.TABLE_NAME); 
    onCreate(db); 
} 




} 

这里是MYDB文件：

package com.cookbook.data; 


import com.example.classorganizer.Diary; 

import android.content.ContentValues; 
import android.content.Context; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteException; 
import android.util.Log; 

public class MyDB { 
private static final String TABLE_NAME = null; 
private static final String KEY_ID = null; 
private SQLiteDatabase db; 
private final Context context; 
private final MyDBhelper dbhelper; 



// Initializes MyDBHelper instance 
public MyDB(Context c){ 

    context = c; 
    dbhelper = new MyDBhelper(context, Constants.DATABASE_NAME, null, 
             Constants.DATABASE_VERSION); 

} 


// Closes the database connection 
public void close() 
{ 
    db.close(); 

} 

// Initializes a SQLiteDatabase instance using MyDBhelper 
public void open() throws SQLiteException 
{ 

    try { 
     db = dbhelper.getWritableDatabase(); 
    } catch(SQLiteException ex) { 
     Log.v("Open database exception caught", ex.getMessage()); 
     db = dbhelper.getReadableDatabase(); 
    } 

} 

// updates a diary entry (existing row) 
    public boolean updateDiaryEntry(String title, long rowId) 
    { 

     ContentValues newValue = new ContentValues(); 
     newValue.put(Constants.TITLE_NAME, title); 

     return db.update(Constants.TABLE_NAME, newValue, Constants.KEY_ID + "=" + rowId, null)>0; 

    } 

// Reads the diary entries from database, saves them in a Cursor class and returns it from the method 
public Cursor getdiaries() 
{ 
    Cursor c = db.query(Constants.TABLE_NAME, null, null, 
         null, null, null, null); 
    return c; 
} 


} 

这里是输出在新建行的文件清单：

package com.example.classorganizer; 


import java.util.ArrayList; 

import android.app.ListActivity; 
import android.content.Context; 
import android.content.Intent; 
import android.database.Cursor; 
import android.os.Bundle; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.AdapterView; 
import android.widget.BaseAdapter; 
import android.widget.ListView; 
import android.widget.TextView; 

import com.cookbook.data.Constants; 
import com.cookbook.data.MyDB; 




public class Monday extends ListActivity { 



private static final int MyMenu = 0; 
MyDB dba; 
DiaryAdapter myAdapter; 

private class MyDiary{ 
    public MyDiary(String t, String c){ 
     title=t; 
     content=c; 

     ListView listView = new ListView(Monday.this); 
     listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() { 
      @Override 
      public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) { 
       new EditListItemDialog(view.getContext()).show(); 

       return true; 


      } 
     }); 


} 

    public String title; 
    public String content; 

} 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    dba = new MyDB(this); 
    dba.open(); 
    setContentView(R.layout.fragment_monday); 





    super.onCreate(savedInstanceState); 
    myAdapter = new DiaryAdapter(this); 
    this.setListAdapter(myAdapter); 
} 



private class DiaryAdapter extends BaseAdapter { 
    private LayoutInflater mInflater; 
    private ArrayList<MyDiary> fragment_monday; 
    public DiaryAdapter(Context context) { 
     mInflater = LayoutInflater.from(context); 
     fragment_monday = new ArrayList<MyDiary>(); 
     getdata(); 


    } 

    public void getdata(){ 
     Cursor c = dba.getdiaries(); 
     startManagingCursor(c); 
     if(c.moveToFirst()){ 
      do{ 
       String title = 
         c.getString(c.getColumnIndex(Constants.TITLE_NAME)); 
       String content = 
         c.getString(c.getColumnIndex(Constants.CONTENT_NAME)); 

       MyDiary temp = new MyDiary(title,content); 
       fragment_monday.add(temp); 
      } while(c.moveToNext()); 
     } 

    } 



    @Override 
    public int getCount() {return fragment_monday.size();} 
    public MyDiary getItem(int i) {return fragment_monday.get(i);} 
    public long getItemId(int i) {return i;} 
    public View getView(int arg0, View arg1, ViewGroup arg2) { 
     final ViewHolder holder; 

     View v = arg1; 
     if ((v == null) || (v.getTag() == null)) { 
      v = mInflater.inflate(R.layout.diaryrow, null); 
      holder = new ViewHolder(); 
      holder.mTitle = (TextView)v.findViewById(R.id.name); 

      v.setTag(holder); 
     } else { 
      holder = (ViewHolder) v.getTag(); 
     } 

     holder.mdiary = getItem(arg0); 
     holder.mTitle.setText(holder.mdiary.title); 


     v.setTag(holder); 

     return v; 


    } 

    public class ViewHolder { 
     MyDiary mdiary; 
     TextView mTitle; 


    } 

} 




/** Called when the user clicks the Edit button */ 
public void visitDiary(View view) { 
    Intent intent = new Intent(this, Diary.class); 
    startActivity(intent); 
} 
/** Called when the user clicks the back button */ 
public void visitSchedule(View view) { 
    Intent intent = new Intent(this, DisplayScheduleScreen.class); 
    startActivity(intent); 
} 


} 

Answer 1

的问题是这一行：

Constants.CONTENT_NAME+" text not null, " 

删除最后一个逗号，并添加右括号：

Constants.CONTENT_NAME+" text not null)" 

Answer 2

这是你的问题：SQLiteException: no such table: diaries。

检查表是否已在数据库中创建，然后再尝试从中进行选择。

Answer 3

这是你的问题：

no such table: diaries 

问题是最有可能的，因为你说你重新安装应用程序，您尚未创建数据库，或者你从选择表。

编辑：现在您发布的数据库创建脚本，有一个语法错误：

private static final String CREATE_TABLE="create table "+ 
Constants.TABLE_NAME+" ("+ 
Constants.KEY_ID+" integer primary key autoincrement, "+ 
Constants.TITLE_NAME+" text not null, "+ 
Constants.CONTENT_NAME+" text not null, " 
; 

你要走Constants.TABLE_NAME后的括号开。 Constants.CONTENT_NAME后，写：+" text not null)"

Answer 4

你onCreate()具有SQL语法问题，但你赶上SQLiteException所以框架认为表创建成功。你不应该在sqlite助手生命周期方法中捕捉异常。如果有问题，应该传播给调用者，而不是默默地忽略。

至于语法问题，

private static final String CREATE_TABLE="create table "+ 
Constants.TABLE_NAME+" ("+ 
Constants.KEY_ID+" integer primary key autoincrement, "+ 
Constants.TITLE_NAME+" text not null, "+ 
Constants.CONTENT_NAME+" text not null, " 
; 

应该像

private static final String CREATE_TABLE="create table "+ 
Constants.TABLE_NAME+" ("+ 
Constants.KEY_ID+" integer primary key autoincrement, "+ 
Constants.TITLE_NAME+" text not null, "+ 
Constants.CONTENT_NAME+" text not null)" 
;