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我的應用程序每次啓動時都會崩潰！它出什麼問題了？我創建了一個數據庫，我試圖從數據庫填充我的列表視圖我已經創建了什麼是代碼問題，它有什麼修復？啓動活動時出錯
02-19 22:02:07.502: D/AndroidRuntime(330): Shutting down VM
02-19 22:02:07.502: W/dalvikvm(330): threadid=1: thread exiting with uncaught exception (group=0x40015560)
02-19 22:02:07.542: E/AndroidRuntime(330): FATAL EXCEPTION: main
02-19 22:02:07.542: E/AndroidRuntime(330): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.database/com.example.database.MainActivity}: java.lang.ClassNotFoundException: com.example.database.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.example.database-1.apk]
02-19 22:02:07.542: E/AndroidRuntime(330): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1569)
02-19 22:02:07.542: E/AndroidRuntime(330): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
02-19 22:02:07.542: E/AndroidRuntime(330): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
02-19 22:02:07.542: E/AndroidRuntime(330): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
02-19 22:02:07.542: E/AndroidRuntime(330): at android.os.Handler.dispatchMessage(Handler.java:99)
02-19 22:02:07.542: E/AndroidRuntime(330): at android.os.Looper.loop(Looper.java:123)
02-19 22:02:07.542: E/AndroidRuntime(330): at android.app.ActivityThread.main(ActivityThread.java:3683)
02-19 22:02:07.542: E/AndroidRuntime(330): at java.lang.reflect.Method.invokeNative(Native Method)
02-19 22:02:07.542: E/AndroidRuntime(330): at java.lang.reflect.Method.invoke(Method.java:507)
02-19 22:02:07.542: E/AndroidRuntime(330): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
02-19 22:02:07.542: E/AndroidRuntime(330): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
02-19 22:02:07.542: E/AndroidRuntime(330): at dalvik.system.NativeStart.main(Native Method)
02-19 22:02:07.542: E/AndroidRuntime(330): Caused by: java.lang.ClassNotFoundException: com.example.database.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.example.database-1.apk]
02-19 22:02:07.542: E/AndroidRuntime(330): at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:240)
02-19 22:02:07.542: E/AndroidRuntime(330): at java.lang.ClassLoader.loadClass(ClassLoader.java:551)
02-19 22:02:07.542: E/AndroidRuntime(330): at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
02-19 22:02:07.542: E/AndroidRuntime(330): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
02-19 22:02:07.542: E/AndroidRuntime(330): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1561)
02-19 22:02:07.542: E/AndroidRuntime(330): ... 11 more
02-19 22:10:47.354: D/AndroidRuntime(364): Shutting down VM
02-19 22:10:47.444: W/dalvikvm(364): threadid=1: thread exiting with uncaught exception (group=0x40015560)
02-19 22:10:47.482: E/AndroidRuntime(364): FATAL EXCEPTION: main
02-19 22:10:47.482: E/AndroidRuntime(364): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.database/com.example.database.MainActivity}: java.lang.ClassNotFoundException: com.example.database.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.example.database-2.apk]
02-19 22:10:47.482: E/AndroidRuntime(364): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1569)
02-19 22:10:47.482: E/AndroidRuntime(364): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
02-19 22:10:47.482: E/AndroidRuntime(364): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
02-19 22:10:47.482: E/AndroidRuntime(364): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
02-19 22:10:47.482: E/AndroidRuntime(364): at android.os.Handler.dispatchMessage(Handler.java:99)
02-19 22:10:47.482: E/AndroidRuntime(364): at android.os.Looper.loop(Looper.java:123)
02-19 22:10:47.482: E/AndroidRuntime(364): at android.app.ActivityThread.main(ActivityThread.java:3683)
02-19 22:10:47.482: E/AndroidRuntime(364): at java.lang.reflect.Method.invokeNative(Native Method)
02-19 22:10:47.482: E/AndroidRuntime(364): at java.lang.reflect.Method.invoke(Method.java:507)
02-19 22:10:47.482: E/AndroidRuntime(364): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
02-19 22:10:47.482: E/AndroidRuntime(364): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
02-19 22:10:47.482: E/AndroidRuntime(364): at dalvik.system.NativeStart.main(Native Method)
02-19 22:10:47.482: E/AndroidRuntime(364): Caused by: java.lang.ClassNotFoundException: com.example.database.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.example.database-2.apk]
02-19 22:10:47.482: E/AndroidRuntime(364): at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:240)
02-19 22:10:47.482: E/AndroidRuntime(364): at java.lang.ClassLoader.loadClass(ClassLoader.java:551)
02-19 22:10:47.482: E/AndroidRuntime(364): at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
02-19 22:10:47.482: E/AndroidRuntime(364): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
02-19 22:10:47.482: E/AndroidRuntime(364): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1561)
02-19 22:10:47.482: E/AndroidRuntime(364): ... 11 more
02-19 22:11:10.302: I/Process(364): Sending signal. PID: 364 SIG: 9
02-19 22:11:17.712: D/AndroidRuntime(413): Shutting down VM
02-19 22:11:17.712: W/dalvikvm(413): threadid=1: thread exiting with uncaught exception (group=0x40015560)
02-19 22:11:17.852: E/AndroidRuntime(413): FATAL EXCEPTION: main
02-19 22:11:17.852: E/AndroidRuntime(413): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.database/com.example.database.MainActivity}: java.lang.ClassNotFoundException: com.example.database.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.example.database-2.apk]
02-19 22:11:17.852: E/AndroidRuntime(413): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1569)
02-19 22:11:17.852: E/AndroidRuntime(413): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
02-19 22:11:17.852: E/AndroidRuntime(413): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
02-19 22:11:17.852: E/AndroidRuntime(413): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
02-19 22:11:17.852: E/AndroidRuntime(413): at android.os.Handler.dispatchMessage(Handler.java:99)
02-19 22:11:17.852: E/AndroidRuntime(413): at android.os.Looper.loop(Looper.java:123)
02-19 22:11:17.852: E/AndroidRuntime(413): at android.app.ActivityThread.main(ActivityThread.java:3683)
02-19 22:11:17.852: E/AndroidRuntime(413): at java.lang.reflect.Method.invokeNative(Native Method)
02-19 22:11:17.852: E/AndroidRuntime(413): at java.lang.reflect.Method.invoke(Method.java:507)
02-19 22:11:17.852: E/AndroidRuntime(413): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
02-19 22:11:17.852: E/AndroidRuntime(413): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
02-19 22:11:17.852: E/AndroidRuntime(413): at dalvik.system.NativeStart.main(Native Method)
02-19 22:11:17.852: E/AndroidRuntime(413): Caused by: java.lang.ClassNotFoundException: com.example.database.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.example.database-2.apk]
02-19 22:11:17.852: E/AndroidRuntime(413): at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:240)
02-19 22:11:17.852: E/AndroidRuntime(413): at java.lang.ClassLoader.loadClass(ClassLoader.java:551)
02-19 22:11:17.852: E/AndroidRuntime(413): at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
02-19 22:11:17.852: E/AndroidRuntime(413): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
02-19 22:11:17.852: E/AndroidRuntime(413): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1561)
02-19 22:11:17.852: E/AndroidRuntime(413): ... 11 more
02-19 22:11:19.852: I/Process(413): Sending signal. PID: 413 SIG: 9
活動：
package com.example.database;
import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
public class AndroidSQLite extends Activity {
private DBHelper mySQLiteAdapter;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView listContent = (ListView)findViewById(R.id.contentlist);
/*
* Create/Open a SQLite database
* and fill with dummy content
* and close it
*/
mySQLiteAdapter = new DBHelper(this);
mySQLiteAdapter.openToWrite();
mySQLiteAdapter.deleteAll();
mySQLiteAdapter.insert("A for Apply");
mySQLiteAdapter.insert("B for Boy");
mySQLiteAdapter.insert("C for Cat");
mySQLiteAdapter.insert("D for Dog");
mySQLiteAdapter.insert("E for Egg");
mySQLiteAdapter.insert("F for Fish");
mySQLiteAdapter.insert("G for Girl");
mySQLiteAdapter.insert("H for Hand");
mySQLiteAdapter.insert("I for Ice-scream");
mySQLiteAdapter.insert("J for Jet");
mySQLiteAdapter.insert("K for Kite");
mySQLiteAdapter.insert("L for Lamp");
mySQLiteAdapter.insert("M for Man");
mySQLiteAdapter.insert("N for Nose");
mySQLiteAdapter.insert("O for Orange");
mySQLiteAdapter.insert("P for Pen");
mySQLiteAdapter.insert("Q for Queen");
mySQLiteAdapter.insert("R for Rain");
mySQLiteAdapter.insert("S for Sugar");
mySQLiteAdapter.insert("T for Tree");
mySQLiteAdapter.insert("U for Umbrella");
mySQLiteAdapter.insert("V for Van");
mySQLiteAdapter.insert("W for Water");
mySQLiteAdapter.insert("X for X'mas");
mySQLiteAdapter.insert("Y for Yellow");
mySQLiteAdapter.insert("Z for Zoo");
mySQLiteAdapter.close();
/*
* Open the same SQLite database
* and read all it's content.
*/
mySQLiteAdapter = new DBHelper(this);
mySQLiteAdapter.openToRead();
Cursor cursor = mySQLiteAdapter.queueAll();
startManagingCursor(cursor);
String[] from = new String[]{DBHelper.KEY_CONTENT};
int[] to = new int[]{R.id.text};
SimpleCursorAdapter cursorAdapter =
new SimpleCursorAdapter(this, R.layout.row, cursor, from, to);
listContent.setAdapter(cursorAdapter);
mySQLiteAdapter.close();
}}
數據庫類
package com.example.database;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
public class DBHelper {
public static final String MYDATABASE_NAME = "MY_DATABASE";
public static final String MYDATABASE_TABLE = "MY_TABLE";
public static final int MYDATABASE_VERSION = 1;
public static final String KEY_ID = "_id";
public static final String KEY_CONTENT = "Content";
//create table MY_DATABASE (ID integer primary key, Content text not null);
private static final String SCRIPT_CREATE_DATABASE =
"create table " + MYDATABASE_TABLE + " ("
+ KEY_ID + " integer primary key autoincrement, "
+ KEY_CONTENT + " text not null);";
private SQLiteHelper sqLiteHelper;
private SQLiteDatabase sqLiteDatabase;
private Context context;
public DBHelper(Context c){
context = c;
}
public DBHelper openToRead() throws android.database.SQLException {
sqLiteHelper = new SQLiteHelper(context, MYDATABASE_NAME, null, MYDATABASE_VERSION);
sqLiteDatabase = sqLiteHelper.getReadableDatabase();
return this;
}
public DBHelper openToWrite() throws android.database.SQLException {
sqLiteHelper = new SQLiteHelper(context, MYDATABASE_NAME, null, MYDATABASE_VERSION);
sqLiteDatabase = sqLiteHelper.getWritableDatabase();
return this;
}
public void close(){
sqLiteHelper.close();
}
public long insert(String content){
ContentValues contentValues = new ContentValues();
contentValues.put(KEY_CONTENT, content);
return sqLiteDatabase.insert(MYDATABASE_TABLE, null, contentValues);
}
public int deleteAll(){
return sqLiteDatabase.delete(MYDATABASE_TABLE, null, null);
}
public Cursor queueAll(){
String[] columns = new String[]{KEY_ID, KEY_CONTENT};
Cursor cursor = sqLiteDatabase.query(MYDATABASE_TABLE, columns,
null, null, null, null, null);
return cursor;
}
public class SQLiteHelper extends SQLiteOpenHelper {
public SQLiteHelper(Context context, String name,
CursorFactory factory, int version) {
super(context, name, factory, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL(SCRIPT_CREATE_DATABASE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}
}
您的活動名稱是「AndroidSQLite」，MainActivity在哪裏？如果您使用正確的活動名稱，您可以檢查AndroidManifest.xml嗎？ – Prakash
您不應對主線程將數據庫操作從onCreate移動到某些AsyncTask，否則有時您可能會收到ANR。 – Prakash