我昨晚遇到一个严重的问题，这个项目（使用外部数据库）在虚拟监视器中运行得非常好
API 22，Android 1.5（Google API）
但如果我在手机上跑，
（Android 5.1，API 22）
它会返回错误：
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.hamira.wordmatchinggame, PID: 12466
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.hamira.wordmatchinggame/com.example.hamira.wordmatchinggame.LeaderBoard}: android.database.sqlite.SQLiteException: no such table: player (code 1): , while compiling: SELECT _id, pname, escr, dscr, hscr, tscr FROM player ORDER BY tscr DESC
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2525)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2617)
at android.app.ActivityThread.access$800(ActivityThread.java:182)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1474)
at android.os.Handler.dispatchMessage(Handler.java:111)
at android.os.Looper.loop(Looper.java:218)
at android.app.ActivityThread.main(ActivityThread.java:5657)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:990)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:785)
Caused by: android.database.sqlite.SQLiteException: no such table: player (code 1): , while compiling: SELECT _id, pname, escr, dscr, hscr, tscr FROM player ORDER BY tscr DESC
at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:898)
at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:509)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1346)
at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1193)
at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1064)
at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1270)
at com.example.hamira.wordmatchinggame.DataConn.displayLeaderBoard(DataConn.java:187)
at com.example.hamira.wordmatchinggame.LeaderBoard.list(LeaderBoard.java:79)
at com.example.hamira.wordmatchinggame.LeaderBoard.onCreate(LeaderBoard.java:35)
at android.app.Activity.performCreate(Activity.java:6135)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1112)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2472)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2617)
at android.app.ActivityThread.access$800(ActivityThread.java:182)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1474)
at android.os.Handler.dispatchMessage(Handler.java:111)
at android.os.Looper.loop(Looper.java:218)
at android.app.ActivityThread.main(ActivityThread.java:5657)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:990)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:785)
I/Process: Sending signal. PID: 12466 SIG: 9
Application terminated.
我的代码：
MainActivity.java
public class LeaderBoard extends Activity {
DataConn myDb;
Intent back;
AlertDialog.Builder bld;
String[] fromFieldNames;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_leaderboard);
back = new Intent(LeaderBoard.this, MainActivity.class);
myDb = new DataConn(this);
list();
});
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
public void list() {
Cursor csr = myDb.displayLeaderBoard(); //<-----------error
fromFieldNames = new String[]{"pname", "escr", "dscr", "hscr", "tscr"};
int[] toView = new int[]{R.id.layoutpname, R.id.layouteasyscore, R.id.layoutdifficultscore, R.id.layouthardscore, R.id.layouttotalscore};
SimpleCursorAdapter myAdapter;
myAdapter = new SimpleCursorAdapter(getBaseContext(), R.layout.lblist, csr, fromFieldNames, toView, 0);
ListView PlayerList = (ListView) findViewById(R.id.listplayer);
PlayerList.setAdapter(myAdapter);
}
DataConn.java
public class DataConn extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "db_egame.db";
private static final String DB_PATH = "data/data/com.example.hamira.wordmatchinggame/databases/";
private static final String TABLE_NAME = "easy";
private SQLiteDatabase db;
static int taksi, pamato;
private final Context myContext;
int jerbang;
public DataConn(Context context) {
super(context, DATABASE_NAME, null, 1);
// SQLiteDatabase db = this.getWritableDatabase();
this.myContext = context;
}
/**
* Creates a empty database on the system and rewrites it with your own database.
* */
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if(dbExist){
//do nothing - database already exist
}else{
//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
/**
* Check if the database already exist to avoid re-copying the file each time you open the application.
* @return true if it exists, false if it doesn't
*/
private boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH + DATABASE_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e){
//database does't exist yet.
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null ? true : false;
}
/**
* Copies your database from your local assets-folder to the just created empty database in the
* system folder, from where it can be accessed and handled.
* This is done by transfering bytestream.
* */
private void copyDataBase() throws IOException{
//Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DATABASE_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DATABASE_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException {
//Open the database
String myPath = DB_PATH + DATABASE_NAME;
db = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}
@Override
public synchronized void close() {
if(db != null)
db.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table "+TABLE_NAME+" (_id INTEGER, ctrlno INTEGER, prima INTEGER, keyword TEXT, val VARCHAR(MAX))");
db.execSQL("CREATE TABLE IF NOT EXISTS easy (_id INTEGER, ctrlno INTEGER, prima INTEGER, keyword TEXT, val VARCHAR);");
db.execSQL("CREATE TABLE IF NOT EXISTS diff (_id INTEGER, ctrlno INTEGER, prima INTEGER, keyword TEXT, val VARCHAR);");
db.execSQL("CREATE TABLE IF NOT EXISTS player (_id INTEGER,pname VARCHAR, escr INTEGER, dscr INTEGER, hscr INTEGER, tscr INTEGER);");
db.close();
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("drop table if exists "+TABLE_NAME);
db.execSQL("drop table if exists easy");
onCreate(db);
}
public Cursor displayLeaderBoard(){
SQLiteDatabase db = this.getWritableDatabase();
String where = null;
String LB_TABLE = "player";
String[] LB_COLUMNS = new String[] {"_id","pname","escr","dscr","hscr","tscr"};
String LB_SORT = "tscr DESC";
Cursor lb = db.query(LB_TABLE, LB_COLUMNS,where,null,null,null,LB_SORT,null);
if(lb !=null){
lb.moveToFirst();
}
return lb;
}
}
其他
我不认为我的代码有问题，因为如果是，那么为什么它在VM（API 22）中完美运行？
是在我的AndroidManifest.xml吗？或Build.Gradle?
的AndroidManifest.xml
package="com.example.hamira.wordmatchinggame">
<application
android:allowBackup="true"
android:icon="@mipmap/launcher"
android:label="@string/app_name"
android:theme="@style/Theme.AppCompat.Light.NoActionBar">
<uses-sdk
android:targetSdkVersion="23"
android:minSdkVersion="7"
/>
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".ingameinterface"
android:label="@string/app_name">
</activity>
<activity
android:name=".MenuView"
android:label="@string/app_name">
</activity>
<activity
android:name=".PlayerView"
android:label="@string/app_name">
</activity>
<activity
android:name=".LevelView"
android:label="@string/app_name">
</activity>
<activity
android:name=".ingamedifficult"
android:label="@string/app_name">
</activity>
<activity
android:name=".LeaderBoard"
android:label="@string/app_name">
</activity>
</application>
Build.Gradle（app）
apply plugin: 'com.android.application'
android {
compileSdkVersion 23
buildToolsVersion "23.0.1"
defaultConfig {
applicationId "com.example.hamira.wordmatchinggame"
minSdkVersion 7
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.4.0'
compile 'com.readystatesoftware.sqliteasset:sqliteassethelper:+'
}
EDITED
我删除onCreate（（SQLiteDatabase db）方法上的db.close()并将另一个错误返回给其他游标方法。
错误日志：
android.database.sqlite.SQLiteException: no such column: stats (code 1): , while compiling: UPDATE player SET stats = '0'
光标方法：
public Cursor ClearRecentPlayer() {
db = this.getWritableDatabase();
Cursor c = db.rawQuery("UPDATE player SET stats = '0'", null);
c.moveToFirst();
c.close();
return c;
}
答案 0 :(得分：0)
首先，我必须指出你的SQLiteOpenHelper有点奇怪。如果您使用此代码，您可能会遇到一些奇怪的问题。
我不知道您的错误的详细信息，但我很确定关闭onCreate中的数据库是不正确的。
我强烈建议您阅读：https://developer.android.com/training/basics/data-storage/databases.html，并使用为您的项目编写标准SQLiteOpenHelper。这不会占用你的大部分时间。
关于您的另一个问题，我认为在您完成新标准SQLiteOpenHelper后，您将不会面对此问题。
希望这可以帮到你。