如何在 Android Studio 中使用按钮按初始筛选并使用 SQLite 将其显示在另一个活动上
Posted
技术标签:
【中文标题】如何在 Android Studio 中使用按钮按初始筛选并使用 SQLite 将其显示在另一个活动上【英文标题】：How to filter by initial using a button and display it on another activity using SQLite in Android Studio 【发布时间】：2021-07-20 03:04:16 【问题描述】：我正在 android studio 中创建一个访客管理系统应用程序。我有一个 SQLite 数据库，可以在其中存储、添加、删除和查看记录。我现在想使用另一个带有字母 A-Z 的 Activity 作为按钮来点击诸如“A 按钮”之类的按钮，它将带我进入一个新的 Activity 并显示名称以 A 开头的每个用户。
我已经搜索了好几个小时试图找到并弄清楚但什么都找不到。
数据库助手在这里：
public class DatabaseHelper extends SQLiteOpenHelper
public static final String USER_TABLE = "USER_TABLE";
public static final String COLUMN_USER_NAME = "USER_NAME";
public static final String COLUMN_SINGED_IN = "SINGED_IN";
public static final String COLUMN_ID = "ID";
public static final String COLUMN_STAFF_VISITOR = "STAFF_VISITOR";
public DatabaseHelper(@Nullable Context context)
super(context, "user.db", null, 1);
@Override
public void onCreate(SQLiteDatabase db)
String createTableStatement = "CREATE TABLE " + USER_TABLE + " (" + COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + COLUMN_USER_NAME + " TEXT, " + COLUMN_STAFF_VISITOR + " TEXT, " + COLUMN_SINGED_IN + " BOOL )";
db.execSQL(createTableStatement);
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
public boolean addOne(UserModel userModel)
SQLiteDatabase db = this.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(COLUMN_USER_NAME, userModel.getName());
cv.put(COLUMN_STAFF_VISITOR, userModel.getStaff_visitor());
cv.put(COLUMN_SINGED_IN, userModel.isOnSite());
long insert = db.insert(USER_TABLE, null, cv);
if( insert == -1)
return false;
else
return true;
public List<UserModel> getallUsers()
List<UserModel> returnList = new ArrayList<>();
String queryString = "SELECT * FROM " + USER_TABLE;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(queryString, null);
if(cursor.moveToFirst())
//Go through the results (loop). Insert them into a return list to display.
do
int userID = cursor.getInt(0);
String userName = cursor.getString(1);
String staffVisitor = cursor.getString(2);
boolean signedIn = cursor.getInt(3) == 1? true: false;
UserModel newUser = new UserModel(userID, userName, staffVisitor, signedIn);
returnList.add(newUser);
while (cursor.moveToNext());
else
//Fail - do not add to list.
cursor.close();
db.close();
return returnList;
public boolean deleteOne(UserModel userModel)
SQLiteDatabase db = this.getWritableDatabase();
String queryString = " DELETE FROM " + USER_TABLE + " WHERE " + COLUMN_ID + " = " +
userModel.getId();
Cursor cursor = db.rawQuery(queryString, null);
if(cursor.moveToFirst())
cursor.close();
return true;
else
cursor.close();
return false;
public List<UserModel> getSpecificUser()
List<UserModel> returnList = new ArrayList<>();
String queryString = "SELECT * FROM " + USER_TABLE + " WHERE " + COLUMN_USER_NAME + " = " + "[]";
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(queryString, null);
if(cursor.moveToFirst())
//Go through the results (loop). Insert them into a return list to display.
do
int userID = cursor.getInt(0);
String userName = cursor.getString(1);
String staffVisitor = cursor.getString(2);
boolean signedIn = cursor.getInt(3) == 1? true: false;
UserModel newUser = new UserModel(userID, userName, staffVisitor, signedIn);
returnList.add(newUser);
while (cursor.moveToNext());
else
//Fail - do not add to list.
cursor.close();
db.close();
return returnList;
这与管理屏幕一起用于添加、删除和查看所有记录。
我现在需要这个数据库来处理我的员工选择屏幕。这是：
public class Staff_Selection extends Activity implements View.OnClickListener
Button btn_home;
DatabaseHelper databaseHelper;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.staff_selection);
databaseHelper = new DatabaseHelper(Staff_Selection.this);
btn_home = findViewById(R.id.home_4);
Button a = findViewById(R.id.btnAv);
a.setOnClickListener(this);
Button b = findViewById(R.id.btnBv);
b.setOnClickListener(this);
Button c = findViewById(R.id.btnCv);
c.setOnClickListener(this);
Button d = findViewById(R.id.btnDv);
d.setOnClickListener(this);
Button e = findViewById(R.id.btnEv);
e.setOnClickListener(this);
Button f = findViewById(R.id.btnFv);
f.setOnClickListener(this);
Button g = findViewById(R.id.btnGv);
g.setOnClickListener(this);
Button h = findViewById(R.id.btnHv);
h.setOnClickListener(this);
Button i = findViewById(R.id.btnIv);
i.setOnClickListener(this);
Button j = findViewById(R.id.btnJv);
j.setOnClickListener(this);
Button k = findViewById(R.id.btnKv);
k.setOnClickListener(this);
Button l = findViewById(R.id.btnLv);
l.setOnClickListener(this);
Button m = findViewById(R.id.btnMv);
m.setOnClickListener(this);
Button n = findViewById(R.id.btnNv);
n.setOnClickListener(this);
Button o = findViewById(R.id.btnOv);
o.setOnClickListener(this);
Button p = findViewById(R.id.btnPv);
p.setOnClickListener(this);
Button q = findViewById(R.id.btnQv);
q.setOnClickListener(this);
Button r = findViewById(R.id.btnRv);
r.setOnClickListener(this);
Button s = findViewById(R.id.btnSv);
s.setOnClickListener(this);
Button t = findViewById(R.id.btnTv);
t.setOnClickListener(this);
Button u = findViewById(R.id.btnUv);
u.setOnClickListener(this);
Button v = findViewById(R.id.btnVv);
v.setOnClickListener(this);
Button w = findViewById(R.id.btnWv);
w.setOnClickListener(this);
Button x = findViewById(R.id.btnXv);
x.setOnClickListener(this);
Button y = findViewById(R.id.btnYv);
y.setOnClickListener(this);
Button z = (Button) findViewById(R.id.btnZv);
z.setOnClickListener(this);
btn_home.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
openActivityHome();
finish();
);
public void openActivityHome()
Intent intent = new Intent(this, Initial_Screen.class);
startActivity(intent);
@Override
public void onClick(View v)
switch (v.getId())
case R.id.btnAv:
DatabaseHelper databaseHelper = new DatabaseHelper(Staff_Selection.this);
List<UserModel> allUsers = databaseHelper.getSpecificUser();
ShowUsersonListView(databaseHelper);
break;
case R.id.btnBv:
break;
case R.id.btnCv:
break;
case R.id.btnDv:
break;
case R.id.btnEv:
break;
case R.id.btnFv:
break;
case R.id.btnGv:
break;
case R.id.btnHv:
break;
case R.id.btnIv:
break;
case R.id.btnJv:
break;
case R.id.btnKv:
break;
case R.id.btnLv:
break;
case R.id.btnMv:
break;
case R.id.btnNv:
break;
case R.id.btnOv:
break;
case R.id.btnPv:
break;
case R.id.btnQv:
break;
case R.id.btnRv:
break;
case R.id.btnSv:
break;
case R.id.btnTv:
break;
case R.id.btnUv:
break;
case R.id.btnVv:
break;
case R.id.btnWv:
break;
case R.id.btnXv:
break;
case R.id.btnYv:
break;
case R.id.btnZv:
break;
default:
break;
private void ShowUsersonListView(DatabaseHelper databaseHelper)
然后在此屏幕上按下的按钮应更新或显示列表视图或结果列表，具体取决于选择到此屏幕的字母。
public class Name_Display_Staff extends AppCompatActivity
Button btn_home;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.name_display);
btn_home = findViewById(R.id.home_1);
btn_home.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
openActivityHome();
finish();
);
public void openActivityHome()
Intent intent = new Intent(this, Initial_Screen.class);
startActivity(intent);
任何帮助的想法都会很棒，甚至可以提供帮助的文档或视频。
【问题讨论】：
【参考方案1】：也许考虑以下基于您的代码但有很多更改的内容。
MainActivity 相当于您的 Staff_Selection（26 个字母按钮）和 Activity2 相当于你name_Display_Staff（获取传递的数据）MainActivity 相当长，可能容易出现维护问题。很多 MainActivity 已被重写以处理按钮，方法是根据保存按钮字母的 String[] 动态添加按钮。
已添加所选用户的 ListView，单击列表中的用户会将您带到第二个活动 Activity2，这是非常基本的，因为它只是获取 UserModel 并将详细信息写入日志。
列表视图使用 CursorAdapter，即 SimpleCursorAdapter，它是为使用 Cursors 而设计的。MainActivity 使用的布局要简单得多，因为没有定义按钮。对于示例/演示/建议，使用的布局是：-
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_
android:layout_
tools:context=".MainActivity"
android:orientation="vertical">
<LinearLayout
android:id="@+id/buttonlist"
android:layout_
android:layout_
android:orientation="horizontal">
</LinearLayout>
<ListView
android:id="@+id/userlist"
android:layout_
android:layout_>
</ListView>
</LinearLayout>
DatabaseHelper 已被 a) 修改为数据库添加一个类变量（您真的不想打开和关闭数据库）：-
public static final String COLUMN_STAFF_VISITOR = "STAFF_VISITOR";
SQLiteDatabase db; //<<<<<<<<<< ADDED
和b)添加以下2个方法
:-
//* ADDED *//
public UserModel getUserById(long id)
UserModel rv = null;
Cursor csr = db.query(USER_TABLE,null,COLUMN_ID+"=?",new String[]String.valueOf(id),null,null,null);
if (csr.moveToFirst())
rv = new UserModel(
csr.getLong(csr.getColumnIndex(COLUMN_ID)),
csr.getString(csr.getColumnIndex(COLUMN_USER_NAME)),
csr.getString(csr.getColumnIndex(COLUMN_STAFF_VISITOR)),
csr.getInt(csr.getColumnIndex(COLUMN_SINGED_IN))>0
);
csr.close();
return rv;
// ADDED //
public Cursor getUsersByFirstLetter(String firstLetter)
return db.query(USER_TABLE,
new String[]
COLUMN_ID + " AS " + BaseColumns._ID,
COLUMN_USER_NAME,
COLUMN_STAFF_VISITOR,
COLUMN_SINGED_IN
,
COLUMN_USER_NAME + " LIKE ?",
new String[]firstLetter + "%",
null,null,COLUMN_USER_NAME + " ASC",null);
否则DatabaseHelper是原样（您可能需要考虑根据上述方法更改它。）
活动2
这是一个非常基本的活动，旨在展示获取适当 UserModel 的原理。它不利于返回（例如完成 Activity 按钮）。
调用时，它只是从数据库中获取 UserModel 并将详细信息写入日志。
public class Activity2 extends AppCompatActivity
DatabaseHelper databaseHelper;
public final static String MYINTENET_USERID = "ACTIVITY2_USERID";
UserModel um;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_2);
databaseHelper = new DatabaseHelper(this);
um = getuserModel(this.getIntent().getLongExtra(MYINTENET_USERID,-1)); //<<<<<<<<<< gets the UserModel based upon the id passed via the Intent.
Log.d("USERMODELINFO","User is " + um.getName() + " staff_visitor is " + um.getStaff_visitor() + " onsite = " + um.isOnSite() + " ID = " + um.getId());
private UserModel getuserModel(long id)
return databaseHelper.getUserById(id);
MainActivity
如前所述，这是完全不同的：-
按钮是基于常量 ALPHABET 动态添加到其他空的 LinearLayout 的，ID 为 buttonlist（请注意如何添加 $ 以显示灵活性）。按钮的属性是最小的。但是，所选按钮的背景与其他按钮形成鲜明对比。
在演示中并非所有按钮都出现（您需要更改）一个 SimpleCursorAdapter 用于 ListView。
我添加了一种方法来添加一些数据，以便演示中显示一些内容。
:-
public class MainActivity extends AppCompatActivity
public static final String[] ALPHABET = "A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z,$";
private Button[] buttons = new Button[ALPHABET.length];
LinearLayout buttonList;
ListView userList;
Cursor users;
SimpleCursorAdapter sca;
DatabaseHelper databaseHelper;
int buttonBckgrndNormal = 0xFFFFFFFF;
int buttonBckgrndSelected = 0xFFFF0000;
int buttonTextColour = 0xFF000000;
Intent intent;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
databaseHelper = new DatabaseHelper(this);
forTestingAddSomeData();
buttonList = this.findViewById(R.id.buttonlist);
userList = this.findViewById(R.id.userlist);
// Add buttons for Letters of the Alphabet
for(int i = 0;i < ALPHABET.length;i++)
addAButton(i);
setOrResetCursorAdapter("");
//* Setup the List View */
private void setOrResetCursorAdapter(String firstLetter)
users = databaseHelper.getUsersByFirstLetter(firstLetter);
Toast.makeText(this,"retrieved " + users.getCount() + " rows from database.",Toast.LENGTH_SHORT).show();
if (sca == null)
sca = new SimpleCursorAdapter(
this,
android.R.layout.simple_list_item_2,
users,
new String[]
DatabaseHelper.COLUMN_USER_NAME,
DatabaseHelper.COLUMN_STAFF_VISITOR,
new int[]
android.R.id.text1, android.R.id.text2
,0);
userList.setAdapter(sca);
userList.setOnItemClickListener(new AdapterView.OnItemClickListener()
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l)
intent = new Intent(MainActivity.this,Activity2.class);
intent.putExtra(Activity2.MYINTENET_USERID,l);
startActivity(intent);
);
else
sca.swapCursor(users);
//* Add a button dynamically */
private Button addAButton(int i)
buttons[i] = new Button(this);
buttons[i].setBackgroundColor(buttonBckgrndNormal);
buttons[i].setText(ALPHABET[i]);
buttons[i].setTextColor(buttonTextColour);
buttons[i].setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View view)
buttonReset();
view.setBackgroundColor(buttonBckgrndSelected);
setOrResetCursorAdapter(((Button)view).getText().toString());
);
buttonList.addView(buttons[i]);
return buttons[i];
/* Reset ALL buttons as not selected */
private void buttonReset()
for(int i=0; i < buttonList.getChildCount();i++)
buttonList.getChildAt(i).setBackgroundColor(buttonBckgrndNormal);
private void forTestingAddSomeData()
UserModel[] umList = new UserModel[]
new UserModel(1,"Fred","Harriet",false),
new UserModel(2,"Mary","Sarah",false),
new UserModel(1,"Annabel","Zed",false),
new UserModel(1,"Bob","Claire",true)
;
for(UserModel u: umList)
databaseHelper.addOne(u);
结果
应用程序启动时（首次运行时）是：-
点击A按钮和：-
只显示 Annabel
的第一行点击F :-
点击列表中的 Fred :-
带你到Activity2（空显示），日志包括：-
D/USERMODELINFO: User is Fred staff_visitor is Harriet onsite = false ID = 1
【讨论】：
感谢您的帮助！很抱歉，对此很陌生，并且已经陷入困境。以上是关于如何在 Android Studio 中使用按钮按初始筛选并使用 SQLite 将其显示在另一个活动上的主要内容，如果未能解决你的问题，请参考以下文章
请问android studio如何通过代码获得不同时区的时间，比如界面按一下美国的按钮，显示的就是美国的时间