我照例写了个sqlite的数据库创建,及增删改查,运行时报错,错误提示如下:
08-29 05:39:42.716: ERROR/AndroidRuntime(305): FATAL EXCEPTION: main
08-29 05:39:42.716: ERROR/AndroidRuntime(305): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.app.sqlite/com.app.sqlite.MySQLiteOpenHelper}: java.lang.InstantiationException: com.app.sqlite.MySQLiteOpenHelper
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.os.Handler.dispatchMessage(Handler.java:99)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.os.Looper.loop(Looper.java:123)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.ActivityThread.main(ActivityThread.java:4627)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at java.lang.reflect.Method.invokeNative(Native Method)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at java.lang.reflect.Method.invoke(Method.java:521)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at dalvik.system.NativeStart.main(Native Method)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): Caused by: java.lang.InstantiationException: com.app.sqlite.MySQLiteOpenHelper
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at java.lang.Class.newInstanceImpl(Native Method)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at java.lang.Class.newInstance(Class.java:1429)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): ... 11 more有MainActivity类和MySQLiteOpenHelper类,代码如下:
public class MainActivity extends Activity implements OnClickListener{
private Button btn_addOne, btn_deleteone, btn_check, btn_deleteTable,
btn_edit, btn_newTable;
private TextView tv;
private MySQLiteOpenHelper myOpenHelper;// 创建一个继承MySqliteActivity类实例
private SQLiteDatabase mysql ;
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
tv = (TextView)findViewById(R.id.tv_title);
btn_addOne = (Button) findViewById(R.id.sql_addOne);
btn_check = (Button) findViewById(R.id.sql_check);
btn_deleteone = (Button) findViewById(R.id.sql_deleteOne);
btn_deleteTable = (Button) findViewById(R.id.sql_deleteTable);
btn_newTable = (Button) findViewById(R.id.sql_newTable);
btn_edit = (Button) findViewById(R.id.sql_edit);
btn_edit.setOnClickListener(this);
btn_addOne.setOnClickListener(this);
btn_check.setOnClickListener(this);
btn_deleteone.setOnClickListener(this);
btn_deleteTable.setOnClickListener(this);
btn_newTable.setOnClickListener(this);
myOpenHelper = new MySQLiteOpenHelper(this);
}
@Override
public void onClick(View v) {
try{
mysql = myOpenHelper.getWritableDatabase();
if(v == btn_addOne){
ContentValues cv = new ContentValues();
cv.put(MySQLiteOpenHelper.TEXT, "测试新的数据");
mysql.insert(MySQLiteOpenHelper.TABLE_NAME, null, cv);
tv.setText("添加数据成功!点击查看数据库查询");
}else if(v == btn_deleteone){
mysql.delete("himi", MySQLiteOpenHelper.ID+"=1", null);
tv.setText("删除数据成功!点击查看数据库查询");
}else if(v == btn_check){
Cursor cur = mysql.rawQuery("SELECT * FROM"+MySQLiteOpenHelper.TABLE_NAME, null);
if(cur != null){
String temp = "";
int i = 0;
while(cur.moveToNext()){
temp +=cur.getString(0);
temp +=cur.getString(1);
i++;
temp += "";
if(i%3 == 0)
temp += "\n";
}
tv.setText(temp);
}
}else if(v == btn_edit){
ContentValues cv = new ContentValues();
cv.put(MySQLiteOpenHelper.TEXT, "修改后的数据");
mysql.update("himi", cv, "id"+"="+Integer.toString(3), null);
tv.setText("修改数据成功!点击查看数据库查询");
}else if(v == btn_deleteTable){
mysql.execSQL("DROP TABLE himi");
tv.setText("删除表成功!点击查看数据库查询");
}else if(v == btn_newTable){
String TABLE_NAME = "himi";
String ID = "id";
String TEXT = "text";
String str_sql2 = "CREATE TABLE " + TABLE_NAME + "(" + ID
+ " INTEGER PRIMARY KEY AUTOINCREMENT," + TEXT
+ " text );";
mysql.execSQL(str_sql2);
tv.setText("新建表成功!点击查看数据库查询");
}
}catch(Exception e){
tv.setText("操作失败!");
}finally{
mysql.close();
}
}
}public class MySQLiteOpenHelper extends SQLiteOpenHelper {
public final static int VERSION = 1;
public final static String TABLE_NAME = "himi";
public final static String ID = "id";
public final static String TEXT = "text";
public final static String DATABASE_NAME = "Himi.db";
public MySQLiteOpenHelper(Context context) {
super(context, DATABASE_NAME, null, VERSION);
} @Override
public void onCreate(SQLiteDatabase db) {
String str_sql = "CREATE TABLE"+TABLE_NAME+"("+ID+
"INGEGER PRIMARY KEY AUTOINCREMENT,"+TEXT+"text);";
db.execSQL(str_sql);
} @Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.v("Himi", "onUpgrade");
}
08-29 05:39:42.716: ERROR/AndroidRuntime(305): FATAL EXCEPTION: main
08-29 05:39:42.716: ERROR/AndroidRuntime(305): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.app.sqlite/com.app.sqlite.MySQLiteOpenHelper}: java.lang.InstantiationException: com.app.sqlite.MySQLiteOpenHelper
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.os.Handler.dispatchMessage(Handler.java:99)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.os.Looper.loop(Looper.java:123)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.ActivityThread.main(ActivityThread.java:4627)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at java.lang.reflect.Method.invokeNative(Native Method)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at java.lang.reflect.Method.invoke(Method.java:521)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at dalvik.system.NativeStart.main(Native Method)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): Caused by: java.lang.InstantiationException: com.app.sqlite.MySQLiteOpenHelper
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at java.lang.Class.newInstanceImpl(Native Method)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at java.lang.Class.newInstance(Class.java:1429)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
08-29 05:39:42.716: ERROR/AndroidRuntime(305): ... 11 more有MainActivity类和MySQLiteOpenHelper类,代码如下:
public class MainActivity extends Activity implements OnClickListener{
private Button btn_addOne, btn_deleteone, btn_check, btn_deleteTable,
btn_edit, btn_newTable;
private TextView tv;
private MySQLiteOpenHelper myOpenHelper;// 创建一个继承MySqliteActivity类实例
private SQLiteDatabase mysql ;
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
tv = (TextView)findViewById(R.id.tv_title);
btn_addOne = (Button) findViewById(R.id.sql_addOne);
btn_check = (Button) findViewById(R.id.sql_check);
btn_deleteone = (Button) findViewById(R.id.sql_deleteOne);
btn_deleteTable = (Button) findViewById(R.id.sql_deleteTable);
btn_newTable = (Button) findViewById(R.id.sql_newTable);
btn_edit = (Button) findViewById(R.id.sql_edit);
btn_edit.setOnClickListener(this);
btn_addOne.setOnClickListener(this);
btn_check.setOnClickListener(this);
btn_deleteone.setOnClickListener(this);
btn_deleteTable.setOnClickListener(this);
btn_newTable.setOnClickListener(this);
myOpenHelper = new MySQLiteOpenHelper(this);
}
@Override
public void onClick(View v) {
try{
mysql = myOpenHelper.getWritableDatabase();
if(v == btn_addOne){
ContentValues cv = new ContentValues();
cv.put(MySQLiteOpenHelper.TEXT, "测试新的数据");
mysql.insert(MySQLiteOpenHelper.TABLE_NAME, null, cv);
tv.setText("添加数据成功!点击查看数据库查询");
}else if(v == btn_deleteone){
mysql.delete("himi", MySQLiteOpenHelper.ID+"=1", null);
tv.setText("删除数据成功!点击查看数据库查询");
}else if(v == btn_check){
Cursor cur = mysql.rawQuery("SELECT * FROM"+MySQLiteOpenHelper.TABLE_NAME, null);
if(cur != null){
String temp = "";
int i = 0;
while(cur.moveToNext()){
temp +=cur.getString(0);
temp +=cur.getString(1);
i++;
temp += "";
if(i%3 == 0)
temp += "\n";
}
tv.setText(temp);
}
}else if(v == btn_edit){
ContentValues cv = new ContentValues();
cv.put(MySQLiteOpenHelper.TEXT, "修改后的数据");
mysql.update("himi", cv, "id"+"="+Integer.toString(3), null);
tv.setText("修改数据成功!点击查看数据库查询");
}else if(v == btn_deleteTable){
mysql.execSQL("DROP TABLE himi");
tv.setText("删除表成功!点击查看数据库查询");
}else if(v == btn_newTable){
String TABLE_NAME = "himi";
String ID = "id";
String TEXT = "text";
String str_sql2 = "CREATE TABLE " + TABLE_NAME + "(" + ID
+ " INTEGER PRIMARY KEY AUTOINCREMENT," + TEXT
+ " text );";
mysql.execSQL(str_sql2);
tv.setText("新建表成功!点击查看数据库查询");
}
}catch(Exception e){
tv.setText("操作失败!");
}finally{
mysql.close();
}
}
}public class MySQLiteOpenHelper extends SQLiteOpenHelper {
public final static int VERSION = 1;
public final static String TABLE_NAME = "himi";
public final static String ID = "id";
public final static String TEXT = "text";
public final static String DATABASE_NAME = "Himi.db";
public MySQLiteOpenHelper(Context context) {
super(context, DATABASE_NAME, null, VERSION);
} @Override
public void onCreate(SQLiteDatabase db) {
String str_sql = "CREATE TABLE"+TABLE_NAME+"("+ID+
"INGEGER PRIMARY KEY AUTOINCREMENT,"+TEXT+"text);";
db.execSQL(str_sql);
} @Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.v("Himi", "onUpgrade");
}
myOpenHelper = new MySQLiteOpenHelper(this, databasename)
我写的希望对你有用