单击文本视图时编辑SQLite数据
单击文本视图时编辑SQLite数据
提问于 2019-03-31 16:17:29
我想通过单击动态创建的文本视图来更新SQLite数据库中的数据。我的数据库显示了学期的名称、开始日期和结束日期。每个文本视图显示一个学期的数据。当我单击ID Textview时，我想转到一个不同的屏幕，在那里用户可以编辑该特定术语的数据。问题是我不知道如何将文本视图连接到术语ID。文本视图是动态创建的。当单击某个术语的ID文本视图时，用户将转到一个新屏幕，在此她可以编辑现有数据。但是，因为SetText覆盖了之前的术语，所以EditText值只显示最后一个术语。如果我使用append，两个ID都会填写在EditText中。我只想在编辑屏幕上显示一个术语的数据，并且我想要与用户单击的Textview ID相对应的术语。这是用户点击他们想要编辑的术语的代码。ID Textview具有将用户带到下一个屏幕的onclickListeners，在该屏幕中，EditText被所选术语数据填充(这就是它的工作方式) First block of code shows the first screen where the user clicks on the textvew that shows the id of each term
public void ViewAll() {
Cursor res = myDb.getAllData();
if(res.getCount() == 0) {
showMessage("Error", "Nothing Found");
return;
}
StringBuffer buffer = new StringBuffer();
while(res.moveToNext()) {
final LinearLayout layout = (LinearLayout ) findViewById(R.id.LinearLayOut);
final TextView textView1 = new TextView(this);
final TextView textView2 = new TextView(this);
final TextView textView3 = new TextView(this);
final TextView textView4 = new TextView(this);
textView1.append(res.getInt(0)+"\n");
textView2.append("Term Title : "+ res.getString(1)+"\n");
textView3.append("Start Date : "+ res.getString(2)+"\n");
textView4.append("End Date : "+ res.getString(3)+"\n");
textView1.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent myIntent = new Intent(ListTerms.this, EditTerms.class);
startActivity(myIntent);
}
}
);
layout.addView(textView1);
layout.addView(textView2);
layout.addView(textView3);
layout.addView(textView4);
}
} public void onClick(View v) {
Intent myIntent = new Intent(ListTerms.this, EditTerms.class);
startActivity(myIntent);
}
}
);
layout.addView(textView1);
layout.addView(textView2);
layout.addView(textView3);
layout.addView(textView4);
}public void UpdateData() {
saveTermInfoBtn.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
boolean isUpdate = myDb.updateTerm(termId.getText().toString(), inputTerm.getText().toString(), inputStart.getText().toString(), inputEnd.getText().toString());
if (isUpdate == true) {
Toast.makeText(EditTerms.this, "Data Update", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(EditTerms.this, "Data Not Updated", Toast.LENGTH_LONG).show();
}
}
}
);
}
public void ViewAll() {
Cursor res = myDb.getAllData();
if(res.getCount() == 0) {
// show message
showMessage("Error","Nothing found");
return;
}
StringBuffer buffer = new StringBuffer();
while (res.moveToNext()) {
termId.setText(res.getString(0) + "\n");
inputTerm.setText(res.getString(1) + "\n");
inputStart.setText(res.getString(2) + "\n");
inputEnd.setText(res.getString(3) + "\n\n");
}
// Show all data
showMessage("Data",buffer.toString());
}If I use setText only the data of the last term gets displayed If I use append the data of all the terms gets displayed.
回答 1
Stack Overflow用户
回答已采纳
发布于 2019-04-01 08:57:33
我相信这做了您想要做的(而不是更新一行Toast的id列，然后可以通过intent和提取的数据传递)。
它利用每个TextView的标记来存储相应的id
使用DatabaseHelper.java的DatabaseHelper：
public class DatabaseHelper extends SQLiteOpenHelper {
public static final String DBNAME = "school.db";
public static final int DBVERSION = 1;
public static final String TBL_TERM = "term";
public static final String COL_TERM_ID = BaseColumns._ID;
public static final String COL_TERM_TITLE = "title";
public static final String COL_TERM_STARTDATE = "startdate";
public static final String COL_TERM_ENDDATE = "enddate";
SQLiteDatabase mDB;
public DatabaseHelper(Context context) {
super(context, DBNAME, null, 1);
mDB = this.getWritableDatabase();
}
@Override
public void onCreate(SQLiteDatabase db) {
String crt_term_sql = "CREATE TABLE IF NOT EXISTS " + TBL_TERM + "(" +
COL_TERM_ID + " INTEGER PRIMARY KEY, " +
COL_TERM_TITLE + " TEXT, " +
COL_TERM_STARTDATE + " TEXT," +
COL_TERM_ENDDATE + " TEXT" +
")";
db.execSQL(crt_term_sql);
}
public long addTerm(String title, String startdate, String enddate) {
ContentValues cv = new ContentValues();
cv.put(COL_TERM_TITLE,title);
cv.put(COL_TERM_STARTDATE,startdate);
cv.put(COL_TERM_ENDDATE,enddate);
return mDB.insert(TBL_TERM,null,cv);
}
public Cursor getAllData() {
return mDB.query(TBL_TERM,null,null,null,null,null,COL_TERM_STARTDATE + " ASC");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}活动内容:-
public class MainActivity extends AppCompatActivity {
LinearLayout layout;
DatabaseHelper myDB;
Cursor mCsr;
Context mContext;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
layout = this.findViewById(R.id.LinearLayout);
mContext = this;
myDB = new DatabaseHelper(this);
addSomeData();
mCsr = myDB.getAllData();
while (mCsr.moveToNext()) {
LinearLayout ll = new LinearLayout(this);
ll.setOrientation(LinearLayout.HORIZONTAL);
long currentID = mCsr.getLong(mCsr.getColumnIndex(DatabaseHelper.COL_TERM_ID));
addtextView(ll,currentID,mCsr.getString(mCsr.getColumnIndex(DatabaseHelper.COL_TERM_ID)) + " ");
addtextView(ll,currentID,mCsr.getString(mCsr.getColumnIndex(DatabaseHelper.COL_TERM_TITLE))+ " ");
addtextView(ll,currentID,mCsr.getString(mCsr.getColumnIndex(DatabaseHelper.COL_TERM_STARTDATE))+ " ");
addtextView(ll, currentID,mCsr.getString(mCsr.getColumnIndex(DatabaseHelper.COL_TERM_ENDDATE))+ " ");
layout.addView(ll);
}
}
private void addtextView(LinearLayout ll, long tag, String data) {
TextView current_tv = new TextView(this);
current_tv.setTag(String.valueOf(tag)); //<<<<<<<<<< SETS THE TAG with current_id
current_tv.setText(data);
ll.addView(current_tv);
current_tv.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
long id = Long.valueOf((String)v.getTag()); //<<<<<<<<<< RETRIEVES THE id FROM THE TAG
Toast.makeText(mContext,"You clicked on ID " + String.valueOf(id),Toast.LENGTH_SHORT).show();
}
});
}
// JUST TO ADD SOME DATA FOR TESTING (if none exists)
private void addSomeData() {
if (DatabaseUtils.queryNumEntries(myDB.getWritableDatabase(),DatabaseHelper.TBL_TERM) < 1) {
myDB.addTerm("Term 1","2019-01-01","2019-03-31");
myDB.addTerm("Term 2","2019-04-01","2019-06-30");
myDB.addTerm("Term 3","2019-07-01","2019-08-31");
myDB.addTerm("Term 4","2019-09-01","2019-12-31");
}
}
}- 请注意，如果您在层次结构较低的活动中添加/删除/编辑行，则需要重新构建视图。
- 已为每行添加了具有水平方向的LinearLayout。主线布局设置为垂直orientation.
替代方案(典型解决方案)
但是，更容易管理的是ListView (特别是关于更新的数据)。也许可以考虑以下几点作为替代方案。
在活动(本例中为Main2Activity)的布局中，添加一个ListView，例如activity_main2.xml is :-
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".Main2Activity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Terms"
android:layout_marginBottom="20dp"/>
<ListView
android:id="@+id/listview"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</ListView>
</LinearLayout>因为你想要3个TextViews (id不是真正的用户友好，因为它没有任何意义，甚至可能会令人困惑)，然后列表的每一行的另一种布局，例如termlist.xml :-
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/title"
android:layout_width="0dp"
android:layout_weight="6"
android:layout_height="match_parent" />
<TextView
android:id="@+id/startdate"
android:layout_width="0dp"
android:layout_weight="2"
android:layout_height="match_parent" />
<TextView
android:id="@+id/enddate"
android:layout_width="0dp"
android:layout_weight="2"
android:layout_height="match_parent" />
</LinearLayout>DatabaseHelper DatabaseJelper.java保持不变。
MainActivity2.java (作为MainActivity的替代，以便可以检查这两个活动) :-
public class Main2Activity extends AppCompatActivity {
DatabaseHelper myDB;
ListView mylistview;
SimpleCursorAdapter sca;
Cursor mCsr;
Context mContext;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
mContext = this;
mylistview = this.findViewById(R.id.listview);
myDB = new DatabaseHelper(this);
addSomeData();
manageListView();
}
private void manageListView() {
mCsr = myDB.getAllData();
if (sca == null) {
sca = new SimpleCursorAdapter(
this,
R.layout.termlist,mCsr,
new String[]{DatabaseHelper.COL_TERM_TITLE,DatabaseHelper.COL_TERM_STARTDATE,DatabaseHelper.COL_TERM_ENDDATE},
new int[]{R.id.title,R.id.startdate,R.id.enddate},
0
);
mylistview.setAdapter(sca);
mylistview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(mContext,"Your clicked on ID " + String.valueOf(id),Toast.LENGTH_SHORT).show();
}
});
} else {
sca.swapCursor(mCsr);
}
}
// JUST TO ADD SOME TEST DATA IF NOE EXISTS
private void addSomeData() {
if (DatabaseUtils.queryNumEntries(myDB.getWritableDatabase(),DatabaseHelper.TBL_TERM) < 1) {
myDB.addTerm("Term 1","2019-01-01","2019-03-31");
myDB.addTerm("Term 2","2019-04-01","2019-06-30");
myDB.addTerm("Term 3","2019-07-01","2019-08-31");
myDB.addTerm("Term 4","2019-09-01","2019-12-31");
}
}
//ADDED as simply calling manageListView will rebuild the list according to the data
// as such when the activity is returned to from another the List is rebuilt
// (basically the Cursor mCsr is overwritten and then as the SimpleCursorAdapter sca is instantiated
// the Cursor is swappped)
@Override
protected void onResume() {
super.onResume();
manageListView();
}
}结果
Fisrt (动态TextViews)：
另一种选择是:-
在这两种情况下，单击一行都会导致id被吐司(而不是费力地去捕捉Toast)。
- 和
- 都已在安卓10
上进行了测试
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/55439022
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