Android studio 将“活动”中的一行从listview移动到另一个“活动”中的另一个listview
我有两个listview,它们中的每一个都处于不同的活动中。当我长时间单击第一个listview中的任何一行时,将其移动到第二个listview,并且仍然执行与第一个listview中相同的任务(例如打开活动),并且列表视图从strings.xml获取其数据。这是我的代码,请帮助我Android studio 将“活动”中的一行从listview移动到另一个“活动”中的另一个listview,android-studio,listview,android-listview,android-sqlite,android-database,Android Studio,Listview,Android Listview,Android Sqlite,Android Database,我有两个listview,它们中的每一个都处于不同的活动中。当我长时间单击第一个listview中的任何一行时,将其移动到第二个listview,并且仍然执行与第一个listview中相同的任务(例如打开活动),并且列表视图从strings.xml获取其数据。这是我的代码,请帮助我 public class DB_Sqlite extends SQLiteOpenHelper { public static final String BDname = "data.db"; pub
public class DB_Sqlite extends SQLiteOpenHelper {
public static final String BDname = "data.db";
public static final int DBVERSION = 1; /*<<<<< ADDED BUT NOT NEEDED */
public static final String TABLE_FAVOURITES = "mytable";
public static final String FAVOURITES_COL_ID = BaseColumns._ID; /*<<<< use the Android stock ID name*/
public static final String FAVOURITES_COL_NAME = "name";
public static final String FAVOURITES_COL_FAVOURITEFLAG = "favourite_flag"; /*<<<<< NEW COLUMN */
public DB_Sqlite(@Nullable Context context) {
super(context, BDname, null, DBVERSION /*<<<<< used constant above */);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table " + TABLE_FAVOURITES + " (" +
FAVOURITES_COL_ID + " INTEGER PRIMARY KEY," + /*<<<<< AUTOINCREMENT NOT NEEDED AND IS INEFFICIENT */
FAVOURITES_COL_NAME + " TEXT, " +
FAVOURITES_COL_FAVOURITEFLAG + " INTEGER DEFAULT 0" + /*<<<<< COLUMN ADDED */
")");
/* CHANGES HERE BELOW loop adding all Resource names NOT VALUES */
ContentValues cv = new ContentValues();
for (String s: StringResourcesHandling.getAllStringResourceNames()) {
cv.clear();
cv.put(FAVOURITES_COL_NAME,s);
db.insert(TABLE_FAVOURITES,null,cv);
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int i, int i1) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_FAVOURITES);
onCreate(db);
}
public boolean insertData(String name){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(FAVOURITES_COL_NAME, name);
long result = db.insert(TABLE_FAVOURITES,null, contentValues);
if (result == -1)
return false;
else
return true;
}
public Cursor getFavouriteRows(boolean favourites) {
SQLiteDatabase db = this.getWritableDatabase();
String whereclause = FAVOURITES_COL_FAVOURITEFLAG + "=?";
String compare = "<1";
if (favourites) {
compare =">0";
}
return db.query(
TABLE_FAVOURITES,null,
FAVOURITES_COL_FAVOURITEFLAG + compare,
null,null,null,null
);
}
private int setFavourite(long id, boolean favourite_flag) {
SQLiteDatabase db = this.getWritableDatabase();
String whereclause = FAVOURITES_COL_ID + "=?";
String[] whereargs = new String[]{String.valueOf(id)};
ContentValues cv = new ContentValues();
cv.put(FAVOURITES_COL_FAVOURITEFLAG,favourite_flag);
return db.update(TABLE_FAVOURITES,cv,whereclause,whereargs);
}
public int setAsFavourite(long id) {
return setFavourite(id,true);
}
public int setAsNotFavourite(long id) {
return setFavourite(id, false);
}
/* Getting everything and make MatrixCursor VALUES from Resource names from Cursor with Resource names */
public Cursor getAllDataInCurrentLocale(Context context) {
SQLiteDatabase db = this.getWritableDatabase();
Cursor csr = db.query(TABLE_FAVOURITES,null,null,null,null,null,null);
if (csr.getCount() < 1) return csr;
MatrixCursor mxcsr = new MatrixCursor(csr.getColumnNames(),csr.getCount());
while (csr.moveToNext()) {
mxcsr.addRow(convertCursorRow(context,csr,new String[]{FAVOURITES_COL_NAME}));
}
csr.close();
return mxcsr;
}
public Cursor getDataInCurrentLocaleById(Context context, long id) {
SQLiteDatabase db = this.getWritableDatabase();
String wherepart = FAVOURITES_COL_ID + "=?";
String[] args = new String[]{String.valueOf(id)};
Cursor csr = db.query(TABLE_FAVOURITES,null,wherepart,args,null,null,null);
if (csr.getCount() < 1) return csr;
MatrixCursor mxcsr = new MatrixCursor(csr.getColumnNames(),csr.getCount());
while (csr.moveToNext()) {
mxcsr.addRow(convertCursorRow(context,csr,new String[]{FAVOURITES_COL_NAME}));
}
csr.close();
return mxcsr;
}
/* This getting columns from Cursor into String array (no BLOB handleing)*/
private String[] convertCursorRow(Context context, Cursor csr, String[] columnsToConvert) {
String[] rv = new String[csr.getColumnCount()];
for (String s: csr.getColumnNames()) {
boolean converted = false;
for (String ctc: columnsToConvert) {
if (csr.getType(csr.getColumnIndex(s)) == Cursor.FIELD_TYPE_BLOB) {
//........ would have to handle BLOB here if needed (another question if needed)
}
if (ctc.equals(s)) {
rv[csr.getColumnIndex(s)] = StringResourcesHandling.getStringByName(context,csr.getString(csr.getColumnIndex(s)));
converted = true;
}
} if (!converted) {
rv[csr.getColumnIndex(s)] = csr.getString(csr.getColumnIndex(s));
}
}
return rv;
}
}
public类DB\u Sqlite扩展SQLiteOpenHelper{
公共静态最终字符串BDname=“data.db”;
公共静态最终int DBVERSION=1;/*问题1
问题一,您正试图将光标强制转换为MatrixCursor,但您无法以这种方式将MatrixCursor强制转换为光标(这是通过getAllDataInCurrentLocale方法完成的)
因此,不是:-
getAllDataInCurrentLocale = (MatrixCursor) dbSqlite.getAllDataInCurrentLocale(this);
你想要:-
getAllDataInCurrentLocale = dbSqlite.getAllDataInCurrentLocale(this);
问题2
第二个问题是,在启动另一个活动时,您从未传递额外的意图
就是
(a)
此处没有设置额外目的(启动tc活动时):-
(b)
同样,此处没有设置额外的意图(启动cc活动时):-
也就是说,您正在实例化名为Cursor的游标对象,然后尝试在名为getAllDataInCurrentLocale的游标上使用游标方法,但该游标尚未实例化。相反,您应该使用实例化游标的方法Cursor
您应该改为使用:-
getAllDataInCurrentLocale = dbSqlite.getDataInCurrentLocaleById(this, fav_id);
if (getAllDataInCurrentLocale.moveToFirst()) {
fav_name = getAllDataInCurrentLocale.getString(getAllDataInCurrentLocale.getColumnIndex(FAVOURITES_COL_NAME));
manageNonFavouritesListView();
}
getAllDataInCurrentLocale.close();
i、 e.声明为getAllDataInCurrentLocale的游标是您应该使用的游标,而不是声明另一个游标
问题4
然后,您将得到一个空指针异常,因为您已将其标记为但已实例化的listView1
因此,您需要一行,如(请参见注释):-
listView1=this.findviewbyd(R.id.listView1);//我完全按照你说的做了,对我来说工作很好,但这不是我想要的,我有三个活动,其中一个是游戏列表(Main),第二个是收藏夹列表(cc),第三个是第一个列表(Main)中的一个游戏,我想要的是,当我长时间单击第一个列表中的任何项目时,该项目将移动到活动(cc)中的第二个列表,如果该项目在第一个列表或第二个列表中,当我按下它时,它将打开第三个活动(tc),如果该项目在第二个列表(cc)中我长时间点击了它,它很好地移回到了(主要活动)中的第一个列表,我希望你明白我的想法,非常感谢你的时间。就像你如何帮助我,但两个列表视图在两个不同的活动中,而不是在同一个(主要活动),(cc活动)cc活动是最受欢迎的活动Activity@AhmedZaqout已经展示的原理是一样的,您只需要根据场景调整ir。
getAllDataInCurrentLocale = (MatrixCursor) dbSqlite.getAllDataInCurrentLocale(this);
getAllDataInCurrentLocale = dbSqlite.getAllDataInCurrentLocale(this);
button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, tc.class);
startActivity(intent);
}
});
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
if (i == 0) {
Intent intent = new Intent(MainActivity.this, tc.class);
startActivity(intent);
}
}
});
Cursor cursor = dbSqlite.getDataInCurrentLocaleById(this, fav_id);
if (cursor.moveToFirst()) {
fav_name = cursor.getString(getAllDataInCurrentLocale.getColumnIndex(FAVOURITES_COL_NAME));
manageNonFavouritesListView();
}
cursor.close();
getAllDataInCurrentLocale = dbSqlite.getDataInCurrentLocaleById(this, fav_id);
if (getAllDataInCurrentLocale.moveToFirst()) {
fav_name = getAllDataInCurrentLocale.getString(getAllDataInCurrentLocale.getColumnIndex(FAVOURITES_COL_NAME));
manageNonFavouritesListView();
}
getAllDataInCurrentLocale.close();
listView1 = this.findViewById(R.id.listview1); //<<<<< ADDED note name should match layout so may be different