我正在尝试构建一个简单的应用程序作为学生列表。 MainActivity由 ListView ， EditText 框和一个＆＃39;添加＆＃39;组成。 按钮即可。 我的ListView连接自定义 CursorAdapter ，应用程序使用自定义 SQLiteOpenHelper 数据库。
点击＆＃39;添加＆＃39;按钮 - ＆gt;
将新记录插入到DB - ＆gt;
DB-Record-ID新添加的ListView项目（通过 bindView ）
更新新插入的记录我尝试做的是将ListView项目的 数据库记录ID 传递给新活动，使用Intent.putExtra，但不知道如何在单击的ListView项中获取子文本视图？ （在 onItemClick 中，以获取其文本并将其与新Intent一起传递给新活动）
目的要在新活动中使用DB-Record-ID，因为新活动允许用户更新记录中的等级参数（因此，我需要DB-Record- ID以便在更新时在我的数据库上更新它
有人可以提出解决方案吗？这是所需的代码 -
MainActivity：
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
/* Our DB model to store student objects */
private SqlDbHelper mDB;
/* Custom SQL-Adapter to connect our SQL DB to the ListView */
private SQLAdapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
/* Init fields & needed views */
mDB = new SqlDbHelper(getApplicationContext());
mAdapter = new SQLAdapter(getApplicationContext(), mDB.getAllRows(), false);
final ListView lvStudents = findViewById(R.id.lv_students);
final EditText etName = findViewById(R.id.et_name);
final EditText etGrade = findViewById(R.id.et_grade);
/* Listen to ADD BUTTON clicks */
findViewById(R.id.button_add).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
insertNewRecord(etName.getText().toString(), etGrade.getText().toString());
etName.setText("");
etGrade.setText("");
}
});
/* Set adapter to LV, Listen to list item clicks */
lvStudents.setAdapter(mAdapter);
lvStudents.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
Intent listItemIntent = new Intent(getApplicationContext(), ListItemActivity.class);
// ????????????
// listItemIntent.putExtra("_ID",
// "Get textview.text containing the param in the CLICKED list item);
startActivity(listItemIntent);
}
});
}
/**
* Creates a list item for a student name + grade
* @param name
* @param grade
* @return the new student id in the DB
*/
private long insertNewRecord(final String name, final String grade) {
int gradeInt = -1;
try {
gradeInt = Integer.parseInt(grade);
} catch (NumberFormatException e) {
Log.w(TAG, "Invalid grade entered: " + grade);
}
/* Add the new student to the DB */
final long id = mDB.insertNewStudent(name, gradeInt);
mAdapter.changeCursor(mDB.getAllRows());
return id;
}
}
不确定是否需要，但以防万一 -
SQLAdapter：
final class SQLAdapter extends CursorAdapter {
private LayoutInflater mInflater;
public SQLAdapter(Context context, Cursor c, boolean autoRequery) {
super(context, c, autoRequery);
mInflater = LayoutInflater.from(context);
}
@Override
public View newView(Context context, Cursor cursor, ViewGroup viewGroup) {
return mInflater.inflate(R.layout.lv_line, viewGroup, false);
}
@Override
public void bindView(View view, Context context, Cursor cursor) {
final String name = cursor.getString(cursor.getColumnIndex(SqlDbHelper.KEY_NAME));
final int grade = cursor.getInt(cursor.getColumnIndex(SqlDbHelper.KEY_GRADE));
final long id = cursor.getLong(cursor.getColumnIndex(SqlDbHelper.KEY_ID));
view.findViewById(R.id.ll_line).setBackgroundColor(Color.RED));
((TextView)view.findViewById(R.id.tv_name)).setText(name);
((TextView)view.findViewById(R.id.tv_grade)).setText(String.valueOf(grade));
((TextView)view.findViewById(R.id.tv_id)).setText(String.valueOf(id));
}
}
SqlDbHelper：
final class SqlDbHelper extends SQLiteOpenHelper {
private static final String TAG = "SqlDbHelper";
/* Database version */
public static final int VERSION = 1;
/* Relevant string names, keys represent columns */
public static final String DB_NAME = "StudentsDB";
public static final String TABLE_NAME = "students";
public static final String KEY_ID = "_id";
public static final String KEY_NAME = "Name";
public static final String KEY_GRADE = "Grade";
public SqlDbHelper(Context context) {
super(context, DB_NAME, null, VERSION);
}
@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
/* Create sql command to create new table */
StringBuilder sql = new StringBuilder();
sql.append("CREATE TABLE " + TABLE_NAME + " (")
.append(KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT,")
.append(KEY_NAME + " TEXT,")
.append(KEY_GRADE + " INT")
.append(")");
/* Execute our sql command:
* CREATE TABLE StudentsDB(_id INTEGER PRIMARY KEY, Name TEXT, Grade INT) */
Log.d(TAG, "Query to form table: " + sql.toString());
sqLiteDatabase.execSQL(sql.toString());
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {}
public long insertNewStudent(final String name, final int grade) {
ContentValues cv = new ContentValues();
cv.put(KEY_NAME, name);
cv.put(KEY_GRADE, grade);
return getWritableDatabase().insert(TABLE_NAME, null, cv);
}
public Cursor getAllRows() {
return getReadableDatabase().
rawQuery("SELECT * FROM " + TABLE_NAME, null);
}
}
答案 0 :(得分：1)
传递给long l的第四个参数onItemClick，对于CursorAdapter，是id（即根据光标的_id）。
所以只需listItemIntent.putExtra("_ID",l);
e.g。 ： -
lvStudents.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
Intent listItemIntent = new Intent(getApplicationContext(), ListItemActivity.class);
listItemIntent.putExtra("_ID",l); // ID as per _id in the cursor.
startActivity(listItemIntent);
}
});
谢谢，并且为了问题 - 如何获得任何其他 onItemClick中特定列表项的文本视图文本？将 view.findViewById（id_of_the_text_box）会给我正确的文字吗？
是的，如果你想从被点击的项目中访问一个视图，那么使用（假设TextView，其他任何适合视图的内容）： -
view.findViewById(R.id.your_view_id).getText().toString;
所以应用这个你可以： -
lvStudents.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
Intent listItemIntent = new Intent(getApplicationContext(), ListItemActivity.class);
listItemIntent.putExtra("_ID",l); // ID as per _id in the cursor.
listItemIntent.putExtra("_IDFROMVIEW,
view.findViewByID(R.id.tv_id).getText().toString();
startActivity(listItemIntent);
}
});
即。它在单击的项目视图列表中找到View（ListView的特定子集/分支（又称adapterView）视图列表）。