10-09 15:33:02.030: E/AndroidRuntime(625): FATAL EXCEPTION: main10-09 15:33:02.030: E/AndroidRuntime(625): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{org.dict.db/org.dict.db.MyDatabaseHelper}: java.lang.InstantiationException: can't instantiate class org.dict.db.MyDatabaseHelper; no empty constructor10-09 15:33:02.030: E/AndroidRuntime(625): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1880)10-09 15:33:02.030: E/AndroidRuntime(625): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)10-09 15:33:02.030: E/AndroidRuntime(625): at android.app.ActivityThread.access$600(ActivityThread.java:123)10-09 15:33:02.030: E/AndroidRuntime(625): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)10-09 15:33:02.030: E/AndroidRuntime(625): at android.os.Handler.dispatchMessage(Handler.java:99)10-09 15:33:02.030: E/AndroidRuntime(625): at android.os.Looper.loop(Looper.java:137)10-09 15:33:02.030: E/AndroidRuntime(625): at android.app.ActivityThread.main(ActivityThread.java:4424)10-09 15:33:02.030: E/AndroidRuntime(625): at java.lang.reflect.Method.invokeNative(Native Method)10-09 15:33:02.030: E/AndroidRuntime(625): at java.lang.reflect.Method.invoke(Method.java:511)10-09 15:33:02.030: E/AndroidRuntime(625): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)10-09 15:33:02.030: E/AndroidRuntime(625): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)10-09 15:33:02.030: E/AndroidRuntime(625): at dalvik.system.NativeStart.main(Native Method)10-09 15:33:02.030: E/AndroidRuntime(625): Caused by: java.lang.InstantiationException: can't instantiate class org.dict.db.MyDatabaseHelper; no empty constructor10-09 15:33:02.030: E/AndroidRuntime(625): at java.lang.Class.newInstanceImpl(Native Method)10-09 15:33:02.030: E/AndroidRuntime(625): at java.lang.Class.newInstance(Class.java:1319)10-09 15:33:02.030: E/AndroidRuntime(625): at android.app.Instrumentation.newActivity(Instrumentation.java:1023)10-09 15:33:02.030: E/AndroidRuntime(625): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1871)10-09 15:33:02.030: E/AndroidRuntime(625): ... 11 more 求大佬幫忙看看這是咋回事啊，安卓開發運行的時候出現的問題。
uj5u.com熱心網友回復：
can't instantiate class org.dict.db.MyDatabaseHelperno empty constructor10-09 15:33:02.030: E/AndroidRuntime(625):
你實體化MyDatabaseHelper這個錯誤了 這個沒有空的構造方法 看看你代碼
uj5u.com熱心網友回復：
package org.dict.db;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import org.dict.db.R;public class MyDatabaseHelper extends SQLiteOpenHelper { final String CREATE_TABLE_SQL = "create table dict(_id integer primary key autoincrement , word , detail)"; /** * @param context * @param name * @param version */ protected MyDatabaseHelper(Context context, String name, int version) { super(context, name, null, version); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL(CREATE_TABLE_SQL); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { System.out.println("--------onUpdate Called--------" + oldVersion + "--->" + newVersion); } }
uj5u.com熱心網友回復：
import android.content.Context;import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import org.dict.db.R;
@SuppressWarnings("unused")
public class MyDatabaseHelper extends SQLiteOpenHelper {
final String CREATE_TABLE_SQL =
"create table dict(_id integer primary key autoincrement , word , detail)";
/**
* @param context
* @param name
* @param version
*/
protected MyDatabaseHelper(Context context, String name, int version)
{
super(context, name, null, version);
}
@Override
public void onCreate(SQLiteDatabase db)
{
db.execSQL(CREATE_TABLE_SQL);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
System.out.println("--------onUpdate Called--------"
+ oldVersion + "--->" + newVersion);
}
}
uj5u.com熱心網友回復：
你的MyDatabaseHelper是Activity吧，起的名字花里花哨。Activity是不允許有建構式的，所以你SQLiteOpenHelper的封裝直接扔掉繼承appcompatActivity就行了
uj5u.com熱心網友回復：
是那個public class內個嗎uj5u.com熱心網友回復：
是那個public class.那個嗎
uj5u.com熱心網友回復：
對的，看你這樣問連java入門都沒進，趕緊補補基礎知識吧
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標籤：Android
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