我确实有几个以相同方式设计的应用程序。扩展的应用程序拥有数据库连接，扩展的 SQLiteOpenHelper 拥有所有代码。
这在标准 android 项目中使用时有效。
当扩展应用程序位于库项目中时，它会崩溃。
以下代码是扩展的应用程序类。它位于图书馆项目中。如果在库项目中使用它会崩溃，但如果它是没有库项目的标准 Android 应用程序的一部分，则不会崩溃。我试图将 MyApplication 类从库项目移动到项目中（更改清单中的名称） - 没有成功。
我的猜测，但我只是在这里钓鱼，是 MySQLiteOpenHelper 使用库项目的权限/权限/位置，而不是项目本身。
public class MyApplication extends Application {
private static SQLiteDatabase sqliteDatabase;
private static MySQLiteOpenHelper sqliteOpenHelper;
public static SQLiteDatabase getSqliteDatabase() {
return sqliteDatabase;
}
public static MySQLiteOpenHelper getSqliteOpenHelper() {
return sqliteOpenHelper;
}
@Override
public void onCreate() {
super.onCreate();
MyPreferenceActivity.createSettings(getApplicationContext());
sqliteOpenHelper = new MySQLiteOpenHelper(getApplicationContext());
if (sqliteOpenHelper != null) {
sqliteDatabase = sqliteOpenHelper.getWritableDatabase();
}
}
}
这是扩展 SQLiteOpenHelper 类的一部分：
public class MySQLiteOpenHelper extends SQLiteOpenHelper {
private static final int DATABASEVERSION = 18;
private static final String DATABASENAME = "myproduct.db";
private Context context;
private SQLiteDatabase sqliteDatabase;
private String location;
public MySQLiteOpenHelper(final Context context) {
super(context, DATABASENAME, null, DATABASEVERSION);
this.context = context;
}
@Override
public SQLiteDatabase getWritableDatabase() {
...
try {
if (Tools.isSDCardWriteable() && (fileSdDbDir.exists() || fileSdDb.exists())) {
// Database on SD-card works perfect
// If I use this to create the internal database it fails here too
location = sdDb;
sqliteDatabase = SQLiteDatabase.openOrCreateDatabase(location, null);
int version = sqliteDatabase.getVersion();
if (version != DATABASEVERSION) {
sqliteDatabase.beginTransaction();
try {
if (version == 0) {
onCreate(sqliteDatabase);
} else {
onUpgrade(sqliteDatabase, version, DATABASEVERSION);
}
sqliteDatabase.setVersion(DATABASEVERSION);
sqliteDatabase.setTransactionSuccessful();
} finally {
sqliteDatabase.endTransaction();
}
}
onOpen(sqliteDatabase);
} else {
// internal database fails to create
location = intDb;
sqliteDatabase = super.getWritableDatabase(); <-- fails
}
} catch (Exception exception) {
if (MyPreferenceActivity.DEBUG) Log.d("Exception", exception.getMessage()); <-- crashes
}
return sqliteDatabase;
}
@Override
public void onCreate(final SQLiteDatabase sqliteDatabase) {
//
}
@Override
public void onUpgrade(final SQLiteDatabase sqliteDatabase, final int oldVersion, final int newVersion) {
//
}
...
}
这是图书馆项目的清单：
<?xml version="1.0" encoding="utf-8"?>
<manifest
xmlns:android="http://schemas.android.com/apk/res/android"
package="xxx.yyy.zzzlib.android" >
<uses-sdk
android:minSdkVersion="7"
android:targetSdkVersion="11" />
</manifest>
这是项目清单的一部分：
<?xml version="1.0" encoding="utf-8"?>
<manifest
xmlns:android="http://schemas.android.com/apk/res/android"
android:installLocation="preferExternal"
android:versionCode="41"
android:versionName="5.0.3"
package="xxx.yyy.zzz.android" >
<application
...
android:name="xxx.yyy.zzzlib.android.MyApplication" >
...
</application>
...
<uses-sdk
android:minSdkVersion="7"
android:targetSdkVersion="11" />
</manifest>
我不知道为什么这不起作用。也许是上下文的事情，但错误指向文件。我没有任何线索。
这种方法有问题吗？它在标准的 Android 项目环境中运行完美。
提前谢谢了。
编辑：
Stacktrace 在 Log.d 中显示崩溃，但失败的是数据库调用：
11-04 17:53:56.143: E/AndroidRuntime(1127): FATAL EXCEPTION: main
11-04 17:53:56.143: E/AndroidRuntime(1127): java.lang.RuntimeException: Unable to create application xxx.yyy.zzzlib.android.MyApplication: java.lang.NullPointerException: println needs a message
11-04 17:53:56.143: E/AndroidRuntime(1127): at android.app.ActivityThread.handleBindApplication(ActivityThread.java:3275)
11-04 17:53:56.143: E/AndroidRuntime(1127): at android.app.ActivityThread.access$2200(ActivityThread.java:117)
11-04 17:53:56.143: E/AndroidRuntime(1127): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:969)
11-04 17:53:56.143: E/AndroidRuntime(1127): at android.os.Handler.dispatchMessage(Handler.java:99)
11-04 17:53:56.143: E/AndroidRuntime(1127): at android.os.Looper.loop(Looper.java:130)
11-04 17:53:56.143: E/AndroidRuntime(1127): at android.app.ActivityThread.main(ActivityThread.java:3683)
11-04 17:53:56.143: E/AndroidRuntime(1127): at java.lang.reflect.Method.invokeNative(Native Method)
11-04 17:53:56.143: E/AndroidRuntime(1127): at java.lang.reflect.Method.invoke(Method.java:507)
11-04 17:53:56.143: E/AndroidRuntime(1127): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
11-04 17:53:56.143: E/AndroidRuntime(1127): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
11-04 17:53:56.143: E/AndroidRuntime(1127): at dalvik.system.NativeStart.main(Native Method)
11-04 17:53:56.143: E/AndroidRuntime(1127): Caused by: java.lang.NullPointerException: println needs a message
11-04 17:53:56.143: E/AndroidRuntime(1127): at android.util.Log.println_native(Native Method)
11-04 17:53:56.143: E/AndroidRuntime(1127): at android.util.Log.d(Log.java:137)
11-04 17:53:56.143: E/AndroidRuntime(1127): at xxx.yyy.zzzlib.android.MySQLiteOpenHelper.getWritableDatabase(MySQLiteOpenHelper.java:1493)
11-04 17:53:56.143: E/AndroidRuntime(1127): at xxx.yyy.zzzlib.android.MyApplication.onCreate(MyApplication.java:27)
11-04 17:53:56.143: E/AndroidRuntime(1127): at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:969)
11-04 17:53:56.143: E/AndroidRuntime(1127): at android.app.ActivityThread.handleBindApplication(ActivityThread.java:3272)