当我点击视图按钮时我试图从数据库中获取值，这是另一个导航活动，当我点击查看全部按钮时触发了CustodianViewActivity以在列表视图中显示数据库中的所有值但是在我的情况下，每次我尝试从数据库中查看数据时应用程序崩溃。我不确定我哪里出错了。
数据库类
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 DBHandler extends SQLiteOpenHelper {
private static DBHandler instance;
// Database Name
public static final String DATABASE_NAME ="AssetDB.db";
//Database version
public static final int Databasevr = 1;
//Custodian Table Name
public static final String TABLE_CUSTODIAN = " Custodian";
// Columbs in the Custodian Table
public static final String CUSTODIAN_ID = "_CustID";
public static final String CUSTODIAN_NAME = "CustName";
public static final String CUSTODIAN_DESIGNATION = "CustDesign";
public static final String CUSTODIAN_DEPARTMENT = "CustDepart";private static final String CREATE_TABLE_CUSTODIAN = "CREATE TABLE" + TABLE_CUSTODIAN + "("
+ CUSTODIAN_ID + " INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,"
+ CUSTODIAN_NAME + " TEXT NOT NULL,"
+ CUSTODIAN_DESIGNATION + " TEXT NOT NULL,"
+ CUSTODIAN_DEPARTMENT + " TEXT NOT NULL" + ");";
// constructor passing parameter passing Database name and Database version
public DBHandler(Context ct)
{
super(ct, DATABASE_NAME, null, Databasevr);
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
// Creating the tables
db.execSQL(CREATE_TABLE_CUSTODIAN);
db.execSQL(CREATE_TABLE_ASSET);
Log.d("Tables","Tables have been created");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
// dropping the tables
db.execSQL("DROP TABLE IF EXISTS " + CREATE_TABLE_CUSTODIAN );
db.execSQL("DROP TABLE IF EXISTS " + CREATE_TABLE_ASSET);
// recreate the tables
onCreate(db);
}
public Cursor getAllCustodians(){
try {
SQLiteDatabase db_database = getWritableDatabase();
Cursor cursor = db_database.rawQuery("SELECT * FROM" + TABLE_CUSTODIAN, null);
if (cursor != null) {
return cursor;
} else {
return null;
}
}
catch(Exception e)
{
return null;
}
}}
CustodianViewActivity
package com.example.nfcams;
import android.app.Activity;
import android.content.Context;
import android.database.Cursor;
import android.os.Bundle;
import android.os.Handler;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CursorAdapter;
import android.widget.ListView;
import android.widget.TextView;
public class CustodianViewActivity extends Activity {
ListView CustodianListview;
DBHandler db_database;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_custodian_view);
db_database = new DBHandler(getApplicationContext());
CustodianListview = (ListView) findViewById(R.id.custodianlistView);
new Handler().post(new Runnable() {
@Override
public void run() {
populateCustoListView();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_custodian_view, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
private void populateCustoListView()
{
Cursor c = db_database.getAllCustodians();
CustodianListview.setAdapter(new CustodiansListAdapter(this,c));
}
private class CustodiansListAdapter extends CursorAdapter
{
private Cursor cursor;
public CustodiansListAdapter(Context context, Cursor cur) {
super(context, cur);
cursor = cur;
}
@Override
public void bindView(View view, Context context, Cursor cursor) {
TextView custID = (TextView) view.findViewById(R.id.Custodianid_view);
int CustodID = cursor.getInt(cursor.getColumnIndex("_CustID"));
custID.setText(String.valueOf(CustodID));
TextView name = (TextView) view.findViewById(R.id.Custodianname_view);
String Custname = cursor.getString(cursor.getColumnIndex("CustName"));
name.setText(Custname);
TextView Designation = (TextView) view.findViewById(R.id.CustodianDesignation_view);
String CustDesignation = cursor.getString(cursor.getColumnIndex("CustDesign"));
Designation.setText(CustDesignation);
TextView Department = (TextView) view.findViewById(R.id.CustodianDepartment_view);
String CustDepartment = cursor.getString(cursor.getColumnIndex("CustDepart"));
Department.setText(CustDepartment);
}
@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(context);
View retView = inflater.inflate(R.layout.custodianrow_views, parent, false);
bindView(retView,context,cursor);
return retView;
}
}
}
Custodianview活动布局
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context="com.example.nfcams.CustodianViewActivity">
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/custodianlistView"
android:layout_centerHorizontal="true"
android:layout_alignParentTop="true" />
</RelativeLayout>
列出视图布局
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="@color/list_item_bg"
android:descendantFocusability="blocksDescendants" >
<RelativeLayout
android:id="@+id/layout_item"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<TextView
android:id="@+id/Custodianname_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="6dp" />
<TextView
android:id="@+id/Custodianid_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@+id/Custodianname_view"
android:padding="6dp" />
<TextView
android:id="@+id/CustodianDesignation_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/Custodianid_view"
android:padding="6dp" />
<TextView
android:id="@+id/CustodianDepartment_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/CustodianDesignation_view"
android:padding="6dp" />
</RelativeLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_below="@+id/layout_item"
android:background="@color/view_divider_color" />
</RelativeLayout>
错误记录
05-30 09:42:16.471 1334-1334/com.example.nfcams E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.nfcams, PID: 1334
java.lang.IllegalArgumentException: column '_id' does not exist
at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:303)
at android.widget.CursorAdapter.init(CursorAdapter.java:172)
at android.widget.CursorAdapter.<init>(CursorAdapter.java:120)
at com.example.nfcams.CustodianViewActivity$CustodiansListAdapter.<init>(CustodianViewActivity.java:95)
at com.example.nfcams.CustodianViewActivity.populateCustoListView(CustodianViewActivity.java:84)
at com.example.nfcams.CustodianViewActivity.access$000(CustodianViewActivity.java:17)
at com.example.nfcams.CustodianViewActivity$1.run(CustodianViewActivity.java:42)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:157)
at android.app.ActivityThread.main(ActivityThread.java:5356)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
at dalvik.system.NativeStart.main(Native Method)