I entered the data in slqite database still cursor.getCount() is null and the Error :- Invalid tables
I entered the data in slqite database still cursor.getCount() is null and the Error :- Invalid tables
这是我将数据输入数据库的代码，我正在接收输入数据的 currentrowId，currentrow_id 正在更新，但 cursor.getcount() 仍然为空
SQLiteDatabase dbr = help.getReadableDatabase();
String[] projection = {
columnid,
columnimage,
columnttitle,
columndesription,
columnurl
};
Cursor cursor = dbr.query(tablename, projection, null, null, null, null, null);
Cursor cur = dbr.query(tablename, projection, null, null, null, null, null);
for (int i = 0; i < mModelList1.size(); i++) {
cursor.moveToFirst();
if (cursor.getCount()==0){
Insert_in_a_row(i,1,mModelList1,help);
cur.moveToLast();
Log.d("uniq cursor.getCount()=",""+cursor.getCount()); //here i get the cursor.getcount() null
}
Log.d("fist cursor.getCount()=",""+cursor.getCount());
while (!cursor.isAfterLast()) {
if(cursor.getCount()>0) {
cur.moveToLast();
int Id = cur.getInt(cur.getColumnIndex(columnid)) + 1;
Log.d("size of mModellist ", "" + mModelList1.size());
Insert_in_a_row(i, Id, mModelList1, help);
Log.d("scnd cursor.getCount()=", "" + cur.getCount()); //here i get the cursor.getcount() null
}
cursor.moveToLast();
cursor.moveToNext();
}if(i==mModelList1.size()-1){cursor.close();
cur.close();
dbr.close();}
}
我调用的插入方法 Insert_in_a_row()
public void Insert_in_a_row(int i,int Id,List<NewsModel>
mModelList1,News_dbhelper help){
final SQLiteDatabase dbw = help.getWritableDatabase();
Log.d("size of mModellist ",""+mModelList1.size());
try{ URL ur=new URL(mModelList1.get(i).getimage());
bmp=BitmapFactory.decodeStream(ur.openConnection().getInputStream());
}catch (IOException e){e.printStackTrace();}
byte[] byteimage1 = getBytes(bmp);
ContentValues values = new ContentValues();
values.put(columnid, Id);
values.put(columnimage, byteimage1);
values.put(columnttitle, mModelList1.get(i).getTitle());
values.put(columndesription,mModelList1.get(i).getDescription());
values.put(columnurl, mModelList1.get(i).getUrl());
long currentRow_ID = dbw.insert(tablename, null, values);
if (Id != currentRow_ID) {
//Toast.makeText(con, "Error with saving news", Toast.LENGTH_LONG).show();
Log.d("news was not saved",""+currentRow_ID );// here I'm recieving an updated currentrow_id but cursor.getcount() is still null
} else {
// Toast.makeText(con, "You are having " + currentRow_ID + " News", Toast.LENGTH_LONG).show();
Log.d("news saved on title", ""+currentRow_ID);
}
}
之后，当我通过 getreadabledatabase() 获取记录以从数据库接收数据时，出现错误 Invalid tables means data is not stored in the database
更新错误日志
D/news saved on title: 1
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
D/size of mModellist: 7
I/art: Background partial concurrent mark sweep GC freed 278(23KB) AllocSpace objects, 6(481KB) LOS objects, 37% free, 6MB/10MB, paused 5.591ms total 19.775ms
D/news was not saved: 2
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
D/size of mModellist: 7
D/news was not saved: 3
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
D/size of mModellist: 7
D/news was not saved: 4
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
D/size of mModellist: 7
D/news was not saved: 5
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
D/size of mModellist: 7
D/news was not saved: 6
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
D/size of mModellist: 7
D/news was not saved: 7
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
W/System.err: java.lang.NullPointerException: Attempt to invoke interface method 'boolean android.database.Cursor.moveToFirst()' on a null object reference
W/System.err: at com.Newsforest.android.Newsforest.MainActivity.gatherInformation(MainActivity.java:356)
W/System.err: at com.Newsforest.android.Newsforest.MainActivity.onCreate(MainActivity.java:179)
W/System.err: at android.app.Activity.performCreate(Activity.java:5990)
W/System.err: at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
W/System.err: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
W/System.err: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
W/System.err: at android.app.ActivityThread.access0(ActivityThread.java:151)
W/System.err: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
W/System.err: at android.os.Handler.dispatchMessage(Handler.java:102)
W/System.err: at android.os.Looper.loop(Looper.java:135)
W/System.err: at android.app.ActivityThread.main(ActivityThread.java:5254)
W/System.err: at java.lang.reflect.Method.invoke(Native Method)
W/System.err: at java.lang.reflect.Method.invoke(Method.java:372)
W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
MainActivity 日志消息如下
W/System.err: java.lang.IllegalStateException: Invalid tables
W/System.err: at android.database.sqlite.SQLiteDatabase.findEditTable(SQLiteDatabase.java:973)
W/System.err: at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1163)
W/System.err: at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1034)
W/System.err: at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1202)
W/System.err: at com.Newsforest.android.Newsforest.MainActivity.gatherInformation(MainActivity.java:346)
W/System.err: at com.Newsforest.android.Newsforest.MainActivity.onCreate(MainActivity.java:179)
W/System.err: at android.app.Activity.performCreate(Activity.java:5990)
W/System.err: at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
W/System.err: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
W/System.err: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
W/System.err: at android.app.ActivityThread.access0(ActivityThread.java:151)
W/System.err: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
W/System.err: at android.os.Handler.dispatchMessage(Handler.java:102)
W/System.err: at android.os.Looper.loop(Looper.java:135)
W/System.err: at android.app.ActivityThread.main(ActivityThread.java:5254)
W/System.err: at java.lang.reflect.Method.invoke(Native Method)
W/System.err: at java.lang.reflect.Method.invoke(Method.java:372)
W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
出现错误的MainActivity代码如下
try {//News_dbhelper mdbHelper= new News_dbhelper(this);
SQLiteDatabase db = mdbHelper.getReadableDatabase();
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
queryBuilder.setTables(tablename);
String[] projection = {
columnid,
columnimage,
columnttitle,
columndesription,
columnurl
};
Cursor C= db.query(tablename,
projection,
null,
null,
null,
null,
null);
// Log.d( "gatherInformation: ",""+C.getCount());
C.moveToFirst();
while (C.isAfterLast()){
NewsModel model = new NewsModel();
//Cursor cursor1 = db.rawQuery(" SELECT * FROM " + tablename + " WHERE " + columnid + "=?", new String[]{String.valueOf(j)});
model.setTitle(C.getString(C.getColumnIndex(columnttitle)));
model.setDescription(C.getString(C.getColumnIndex(columndesription)));
model.setUrl(C.getString(C.getColumnIndex(columnurl)));
model.setimage(C.getString(C.getColumnIndex(columnimage)));
mModelList.add(model);
C.moveToNext();
}
C.close();
}catch (SQLiteException e){e.printStackTrace();
Toast.makeText(this,"error reason"+e.toString(),Toast.LENGTH_LONG).show();}
catch (Exception e){e.printStackTrace();}
finally {
Log.d("size of mModellist ",""+mModelList.size());
recyclerView.setAdapter(new Adapter(MainActivity.this,mModelList));
}
仍然显示黑屏而不是 recyclerView
W/CursorWindow: Window is full: requested allocation 892521 bytes, free space 572848 bytes, window size 2097152 bytes
W/CursorWindow: Window is full: requested allocation 617180 bytes, free space 565848 bytes, window size 2097152 bytes
W/CursorWindow: Window is full: requested allocation 675170 bytes, free space 91920 bytes, window size 2097152 bytes
D/size of mModellist: 8
W/ResourcesManager: Asset path '/system/framework/com.android.media.remotedisplay.jar' does not exist or contains no resources.
W/ResourcesManager: Asset path '/system/framework/com.android.location.provider.jar' does not exist or contains no resources.
D/DynamitePackage: Instantiated singleton DynamitePackage.
D/DynamitePackage: Instantiating com.google.android.gms.ads.ChimeraAdManagerCreatorImpl
游标允许您访问查询结果集。查询后插入新数据，查询结果集不会改变。因此光标计数保持在 0.
您需要再次查询数据库才能看到新数据。
在您的 System.err 日志中被视为警告的 NPE 不是由您发布的代码版本产生的。
这是我将数据输入数据库的代码，我正在接收输入数据的 currentrowId，currentrow_id 正在更新，但 cursor.getcount() 仍然为空
SQLiteDatabase dbr = help.getReadableDatabase();
String[] projection = {
columnid,
columnimage,
columnttitle,
columndesription,
columnurl
};
Cursor cursor = dbr.query(tablename, projection, null, null, null, null, null);
Cursor cur = dbr.query(tablename, projection, null, null, null, null, null);
for (int i = 0; i < mModelList1.size(); i++) {
cursor.moveToFirst();
if (cursor.getCount()==0){
Insert_in_a_row(i,1,mModelList1,help);
cur.moveToLast();
Log.d("uniq cursor.getCount()=",""+cursor.getCount()); //here i get the cursor.getcount() null
}
Log.d("fist cursor.getCount()=",""+cursor.getCount());
while (!cursor.isAfterLast()) {
if(cursor.getCount()>0) {
cur.moveToLast();
int Id = cur.getInt(cur.getColumnIndex(columnid)) + 1;
Log.d("size of mModellist ", "" + mModelList1.size());
Insert_in_a_row(i, Id, mModelList1, help);
Log.d("scnd cursor.getCount()=", "" + cur.getCount()); //here i get the cursor.getcount() null
}
cursor.moveToLast();
cursor.moveToNext();
}if(i==mModelList1.size()-1){cursor.close();
cur.close();
dbr.close();}
}
我调用的插入方法 Insert_in_a_row()
public void Insert_in_a_row(int i,int Id,List<NewsModel>
mModelList1,News_dbhelper help){
final SQLiteDatabase dbw = help.getWritableDatabase();
Log.d("size of mModellist ",""+mModelList1.size());
try{ URL ur=new URL(mModelList1.get(i).getimage());
bmp=BitmapFactory.decodeStream(ur.openConnection().getInputStream());
}catch (IOException e){e.printStackTrace();}
byte[] byteimage1 = getBytes(bmp);
ContentValues values = new ContentValues();
values.put(columnid, Id);
values.put(columnimage, byteimage1);
values.put(columnttitle, mModelList1.get(i).getTitle());
values.put(columndesription,mModelList1.get(i).getDescription());
values.put(columnurl, mModelList1.get(i).getUrl());
long currentRow_ID = dbw.insert(tablename, null, values);
if (Id != currentRow_ID) {
//Toast.makeText(con, "Error with saving news", Toast.LENGTH_LONG).show();
Log.d("news was not saved",""+currentRow_ID );// here I'm recieving an updated currentrow_id but cursor.getcount() is still null
} else {
// Toast.makeText(con, "You are having " + currentRow_ID + " News", Toast.LENGTH_LONG).show();
Log.d("news saved on title", ""+currentRow_ID);
}
}
之后，当我通过 getreadabledatabase() 获取记录以从数据库接收数据时，出现错误 Invalid tables means data is not stored in the database
更新错误日志
D/news saved on title: 1
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
D/size of mModellist: 7
I/art: Background partial concurrent mark sweep GC freed 278(23KB) AllocSpace objects, 6(481KB) LOS objects, 37% free, 6MB/10MB, paused 5.591ms total 19.775ms
D/news was not saved: 2
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
D/size of mModellist: 7
D/news was not saved: 3
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
D/size of mModellist: 7
D/news was not saved: 4
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
D/size of mModellist: 7
D/news was not saved: 5
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
D/size of mModellist: 7
D/news was not saved: 6
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
D/size of mModellist: 7
D/news was not saved: 7
D/uniq cursor.getCount()=: 0
D/fist cursor.getCount()=: 0
W/System.err: java.lang.NullPointerException: Attempt to invoke interface method 'boolean android.database.Cursor.moveToFirst()' on a null object reference
W/System.err: at com.Newsforest.android.Newsforest.MainActivity.gatherInformation(MainActivity.java:356)
W/System.err: at com.Newsforest.android.Newsforest.MainActivity.onCreate(MainActivity.java:179)
W/System.err: at android.app.Activity.performCreate(Activity.java:5990)
W/System.err: at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
W/System.err: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
W/System.err: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
W/System.err: at android.app.ActivityThread.access0(ActivityThread.java:151)
W/System.err: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
W/System.err: at android.os.Handler.dispatchMessage(Handler.java:102)
W/System.err: at android.os.Looper.loop(Looper.java:135)
W/System.err: at android.app.ActivityThread.main(ActivityThread.java:5254)
W/System.err: at java.lang.reflect.Method.invoke(Native Method)
W/System.err: at java.lang.reflect.Method.invoke(Method.java:372)
W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
MainActivity 日志消息如下
W/System.err: java.lang.IllegalStateException: Invalid tables
W/System.err: at android.database.sqlite.SQLiteDatabase.findEditTable(SQLiteDatabase.java:973)
W/System.err: at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1163)
W/System.err: at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1034)
W/System.err: at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1202)
W/System.err: at com.Newsforest.android.Newsforest.MainActivity.gatherInformation(MainActivity.java:346)
W/System.err: at com.Newsforest.android.Newsforest.MainActivity.onCreate(MainActivity.java:179)
W/System.err: at android.app.Activity.performCreate(Activity.java:5990)
W/System.err: at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
W/System.err: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
W/System.err: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
W/System.err: at android.app.ActivityThread.access0(ActivityThread.java:151)
W/System.err: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
W/System.err: at android.os.Handler.dispatchMessage(Handler.java:102)
W/System.err: at android.os.Looper.loop(Looper.java:135)
W/System.err: at android.app.ActivityThread.main(ActivityThread.java:5254)
W/System.err: at java.lang.reflect.Method.invoke(Native Method)
W/System.err: at java.lang.reflect.Method.invoke(Method.java:372)
W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
出现错误的MainActivity代码如下
try {//News_dbhelper mdbHelper= new News_dbhelper(this);
SQLiteDatabase db = mdbHelper.getReadableDatabase();
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
queryBuilder.setTables(tablename);
String[] projection = {
columnid,
columnimage,
columnttitle,
columndesription,
columnurl
};
Cursor C= db.query(tablename,
projection,
null,
null,
null,
null,
null);
// Log.d( "gatherInformation: ",""+C.getCount());
C.moveToFirst();
while (C.isAfterLast()){
NewsModel model = new NewsModel();
//Cursor cursor1 = db.rawQuery(" SELECT * FROM " + tablename + " WHERE " + columnid + "=?", new String[]{String.valueOf(j)});
model.setTitle(C.getString(C.getColumnIndex(columnttitle)));
model.setDescription(C.getString(C.getColumnIndex(columndesription)));
model.setUrl(C.getString(C.getColumnIndex(columnurl)));
model.setimage(C.getString(C.getColumnIndex(columnimage)));
mModelList.add(model);
C.moveToNext();
}
C.close();
}catch (SQLiteException e){e.printStackTrace();
Toast.makeText(this,"error reason"+e.toString(),Toast.LENGTH_LONG).show();}
catch (Exception e){e.printStackTrace();}
finally {
Log.d("size of mModellist ",""+mModelList.size());
recyclerView.setAdapter(new Adapter(MainActivity.this,mModelList));
}
仍然显示黑屏而不是 recyclerView
W/CursorWindow: Window is full: requested allocation 892521 bytes, free space 572848 bytes, window size 2097152 bytes
W/CursorWindow: Window is full: requested allocation 617180 bytes, free space 565848 bytes, window size 2097152 bytes
W/CursorWindow: Window is full: requested allocation 675170 bytes, free space 91920 bytes, window size 2097152 bytes
D/size of mModellist: 8
W/ResourcesManager: Asset path '/system/framework/com.android.media.remotedisplay.jar' does not exist or contains no resources.
W/ResourcesManager: Asset path '/system/framework/com.android.location.provider.jar' does not exist or contains no resources.
D/DynamitePackage: Instantiated singleton DynamitePackage.
D/DynamitePackage: Instantiating com.google.android.gms.ads.ChimeraAdManagerCreatorImpl
游标允许您访问查询结果集。查询后插入新数据，查询结果集不会改变。因此光标计数保持在 0.
您需要再次查询数据库才能看到新数据。
在您的 System.err 日志中被视为警告的 NPE 不是由您发布的代码版本产生的。