while(cursor.moveToNext()){ int a1= cursor.getInt(cursor.getColumnIndex("d_head")); descA[i] = a1; String a2 = cursor.getString(cursor.getColumnIndex("d_name")); descB[i] = a2; String a3 = cursor.getString(cursor.getColumnIndex("d_post")); descC[i] = a3; String a4 = cursor.getString(cursor.getColumnIndex("d_type")); descD[i] = a4; String a5 = cursor.getString(cursor.getColumnIndex("d_content")); descE[i] = a5; i++; } h1.setBackgroundResource(descA[num]); //设置控件属性的代码 h2.setText(descB[num]); h3.setText(descC[num]); h4.setText(descD[num]); h5.setText("\u3000\u3000"+descE[num]);//加空格

@SuppressLint("Range") public SendFrameTimeMtc selectFrameTime(long sceneStartTime) { SendFrameTimeMtc sendFrameTimeMtc = new SendFrameTimeMtc(); Cursor cursor = mRDB.query(TABLE_FRAMETIME, null, "scene_start_time=?", new String[]{String.valueOf(sceneStartTime)}, null, null, "_id", null); int batch = 0; long frameTime = 0; long curFrameTime = 0; if (cursor.getCount() > 0){ SendFrameTimeEntity sendFrameTimeEntity = new SendFrameTimeEntity(); while (cursor.moveToNext()) { if (sendFrameTimeEntity.getTs() == 0){ /** * 首次重置批次 */ frameTime = cursor.getLong(cursor.getColumnIndex("frame_time")); sendFrameTimeEntity.setTs(frameTime); batch = cursor.getInt(cursor.getColumnIndex("batch")); }else { if (batch == cursor.getInt(cursor.getColumnIndex("batch"))){ curFrameTime = cursor.getLong(cursor.getColumnIndex("frame_time")); sendFrameTimeEntity.getFtList().add(curFrameTime-frameTime); frameTime = curFrameTime; }else { // 批次不同，重置 sendFrameTimeMtc.getSendFrames().add(sendFrameTimeEntity); sendFrameTimeEntity = new SendFrameTimeEntity(); frameTime = cursor.getLong(cursor.getColumnIndex("frame_time")); sendFrameTimeEntity.setTs(frameTime); batch = cursor.getInt(cursor.getColumnIndex("batch")); } } } sendFrameTimeMtc.getSendFrames().add(sendFrameTimeEntity); } return sendFrameTimeMtc; }

while (cursor.moveToNext()) { int batch = cursor.getInt(batchIndex); long frameTime = cursor.getLong(frameTimeIndex); if (sendFrameTimeEntity.getTs() == 0) { /** 首次重置批次 */ ...

public int FindInventory(DBHelper dbHelper,String bid){ SQLiteDatabase db = dbHelper.getWritableDatabase(); Cursor cursor = db.rawQuery("select inventory from book where id = ?",new String[]{bid}); int number = 0; if (cursor != null && cursor.getCount() > 0){ while (cursor.moveToNext()){ number = cursor.getInt(0); } } return number; } }public ArrayList<Book> SearchCollection(DBHelper dbHelper,String searcher){ SQLiteDatabase db = dbHelper.getWritableDatabase(); Cursor cursor = db.rawQuery("select * from book where id in ("+searcher+")",null); ArrayList<Book> list = new ArrayList<>(); if (cursor != null && cursor.getCount() > 0){ while (cursor.moveToNext()){ String id = cursor.getString(cursor.getColumnIndex("id")); String bookname = cursor.getString(cursor.getColumnIndex("bookname")); String author = cursor.getString(cursor.getColumnIndex("author")); int inventory = cursor.getInt(cursor.getColumnIndex("inventory")); Book book = new Book(id,bookname,author,inventory,2); list.add(book); } } db.close(); return list; }解释每一行代码

int inventory = cursor.getInt(cursor.getColumnIndex("inventory")); //获取查询结果中inventory列的值。 Book book = new Book(id,bookname,author,inventory,2); //创建一个Book类的对象book，将查询结果赋值给...

优化此段代码 @SuppressLint("Range") public JSONArray selectApmList(Long sceneStartTime) { JSONArray apmJsonArray = new JSONArray(); String selection = "scene_start_time=?"; String[] selectionArgs = {String.valueOf(sceneStartTime)}; String orderBy = "_id"; Cursor cursor = mRDB.query(TABLE_PERFORMANCE, null, selection, selectionArgs, null, null, orderBy, null); if (cursor.getCount() > 0) { int tsIndex = cursor.getColumnIndex("ts"); int pssIndex = cursor.getColumnIndex("pss"); int cpuIndex = cursor.getColumnIndex("cpu"); int currentIndex = cursor.getColumnIndex("current"); int voltageIndex = cursor.getColumnIndex("voltage"); int batteryPercentIndex = cursor.getColumnIndex("battery_percent"); while (cursor.moveToNext()) { JSONObject apmEntity = new JSONObject(); JsonUtils.put(apmEntity, ConfigConst.send_apmTsCollect, cursor.getLong(tsIndex)); JsonUtils.put(apmEntity, ConfigConst.send_apmPss, cursor.getLong(pssIndex)); JsonUtils.put(apmEntity, ConfigConst.send_apmCpu, cursor.getLong(cpuIndex)); JsonUtils.put(apmEntity, ConfigConst.send_apmCurrent, cursor.getLong(currentIndex)); JsonUtils.put(apmEntity, ConfigConst.send_apmVoltage, cursor.getLong(voltageIndex)); JsonUtils.put(apmEntity, ConfigConst.send_apmBatteryPercent, cursor.getLong(batteryPercentIndex)); apmJsonArray.put(apmEntity); } return apmJsonArray; } return apmJsonArray; }

} while (cursor.moveToNext()); callback.onSuccess(apmJsonArray); } else { callback.onSuccess(null); } if (cursor != null) { cursor.close(); } } }).start(); } 其中，Callback是自定义的回调...

public class RetrieveDataActivity extends Activity { private String[] columns={ContactsContract.Contacts._ID, ContactsContract.Contacts.DISPLAY_NAME, ContactsContract.CommonDataKinds.Phone.NUMBER, ContactsContract.CommonDataKinds.Phone.CONTACT_ID}; public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); TextView tv=(TextView) findViewById(R.id.result); tv.setText(getQueryData()); } private String getQueryData(){ StringBuilder sb=new StringBuilder(); ContentResolver resolver=getContentResolver(); Cursor cursor=resolver.query(ContactsContract.Contacts.CONTENT_URI,null,null,null,null); while (cursor.moveToNext()){ int idIndex=cursor.getColumnIndex(columns[0]); int displayNameIndex= cursor.getColumnIndex(columns[1]); int id=cursor.getInt(idIndex); String displayName=cursor.getString(displayNameIndex); Cursor phone= resolver.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null,columns[3]+"="+id,null,null); while(phone.moveToNext()){ int phoneNumberIndex=phone.getColumnIndex(columns[2]); String phoneNumber=phone.getString(phoneNumberIndex); sb.append(displayName+":"+phoneNumber+"\n"); cursor.close(); } }

int id = cursor.getInt(idIndex); String displayName = cursor.getString(displayNameIndex); Cursor phone = resolver.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, columns[3] + "=" + ...

public List<NotepadBean> query(){ List<NotepadBean> list=new ArrayList<NotepadBean>(); Cursor cursor=sqLiteDatabase.query(DBUtils.DATABASE_TABLE,null,null,null, null,null,DBUtils.NOTEPAD_ID+" desc"); if(cursor!=null) { while (cursor.moveToNext()) { NotepadBean noteInfo = new NotepadBean(); String id = String.valueOf(cursor.getInt (cursor.getColumnIndex(DBUtils.NOTEPAD_ID))); String content = cursor.getString(cursor.getColumnIndex (DBUtils.NOTEPAD_CONTENT)); String time = cursor.getString(cursor.getColumnIndex (DBUtils.NOTEPAD_TIME)); noteInfo.setId(id); noteInfo.setNotepadContent(content); noteInfo.setNotepadTime(time); list.add(noteInfo); } cursor.close(); } return list; } 以上代码出现这些问题Value must be ≥ 0怎么修改代码，请提供完整代码

可以在调用 cursor.getInt() 之前先调用 cursor.getColumnIndex() 确保该列存在，例如： public List<NotepadBean> query() { List<NotepadBean> list = new ArrayList(); Cursor cursor = ...

下面代码的意思 private void queryTitle() { Cursor cursor1= mDatabase.rawQuery("select count(2) from "+DBHelper.TABLE_NAME,null); cursor1.moveToFirst(); long count = cursor1.getLong(0); int num=(int) count; title=new String[num]; id=new int[num]; cursor1.close(); Cursor cursor; cursor = mDatabase.query(DBHelper.TABLE_NAME,DBHelper.TABLE_COLUMNS,null,null,null,null,null); int i=0; while (cursor != null && cursor.moveToNext()) { id[i]=cursor.getInt(cursor.getColumnIndex(DBHelper.COLUMN_ID)); title[i]=cursor.getString(cursor.getColumnIndex(DBHelper.COLUMN_TITLE)); i+=1; } cursor.close(); } class MyBaseAdapter extends BaseAdapter { @Override public int getCount() { Cursor cursor= mDatabase.rawQuery("select count(2) from "+DBHelper.TABLE_NAME,null); cursor.moveToFirst(); long count = cursor.getLong(0); cursor.close(); int num=(int)count; return num; }

在 getCount() 方法中，先查询数据库中的记录总数，然后关闭游标 cursor，并将记录总数转换为 int 类型并返回。顺便提一下，该程序使用了自定义的 MyBaseAdapter 类继承自 BaseAdapter 类，并且在 ListView 中使用...

public ArrayList<Book> BookDetails(DBHelper dbHelper,String bid){ SQLiteDatabase db = dbHelper.getWritableDatabase(); Cursor cursor = db.query("book",new String[]{"ISBN","bookname","author","press", "publicationtime","category","synopsis","inventory","page"},"id = ?", new String[]{bid + ""},null,null,null); ArrayList<Book> list = new ArrayList<>(); if (cursor != null && cursor.getCount() > 0){ while (cursor.moveToNext()){ String ISBN = cursor.getString(cursor.getColumnIndex("ISBN")); String bookname = cursor.getString(cursor.getColumnIndex("bookname")); String author = cursor.getString(cursor.getColumnIndex("author")); String press = cursor.getString(cursor.getColumnIndex("press")); String publicationtime = cursor.getString(cursor.getColumnIndex("publicationtime")); String category = cursor.getString(cursor.getColumnIndex("category")); String synopsis = cursor.getString(cursor.getColumnIndex("synopsis")); int inventory = cursor.getInt(cursor.getColumnIndex("inventory")); int page = cursor.getInt(cursor.getColumnIndex("page")); Book book = new Book(ISBN,bookname,author,press,publicationtime,category,synopsis,inventory,page); list.add(book); } } db.close(); return list; } //删除图书 public boolean DeleteBook(DBHelper dbHelper,String id){ SQLiteDatabase db = dbHelper.getWritableDatabase(); int flag = db.delete("book","id=?",new String[]{id + ""}); db.close(); boolean result; if (flag == -1){ result = false; }else { result = true; } return result; }解释每一行代码

5. while (cursor.moveToNext()){：遍历查询结果。 6. String ISBN = cursor.getString(cursor.getColumnIndex("ISBN"));：获取查询结果中"ISBN"列的值。 7. String bookname = cursor.getString(cursor....

解释下面代码 private String isExistDH(String name) { DatabaseHelper dbHelper = new DatabaseHelper(this); Cursor cursor=dbHelper.queryDactor(name); String psd=null; while(cursor.moveToNext()){ //moveToNext()移动光标到下一行 psd = cursor.getString(cursor.getColumnIndex("d_head")); } return psd; }

在while循环中，它使用moveToNext方法将光标移动到下一行，并使用getColumnIndex方法获取“d_head”列的索引。然后使用getString方法从该列中检索字符串类型的医生头像信息。最后，它返回psd字符串，该字符串包含...

public ArrayList<Book> BookGrid(DBHelper dbHelper){ SQLiteDatabase db = dbHelper.getWritableDatabase(); Cursor cursor = db.query("book",new String[]{"id","bookname","author","inventory"}, null,null,null,null,"id desc"); ArrayList<Book> list = new ArrayList<>(); if (cursor != null && cursor.getCount() > 0){ while (cursor.moveToNext()){ String id = cursor.getString(cursor.getColumnIndex("id")); String bookname = cursor.getString(cursor.getColumnIndex("bookname")); String author = cursor.getString(cursor.getColumnIndex("author")); int inventory = cursor.getInt(cursor.getColumnIndex("inventory")); Book book = new Book(id,bookname,author,inventory,2); list.add(book); } } db.close(); return list; }解释每一行代码

int inventory = cursor.getInt(cursor.getColumnIndex("inventory")); Book book = new Book(id,bookname,author,inventory,2); list.add(book); 第八行代码关闭数据库连接。 java db.close(); 最后...

DatabaseHelper helper=new DatabaseHelper(Xiaomu_Alldactor.this); Cursor cursor=helper.queryDactor(); // 定义SimpleCursorAdapter int p=0; final int[] desc = new int[cursor.getCount()]; while(cursor.moveToNext()) { int a2 = cursor.getInt(cursor.getColumnIndex("_id")); desc[p] = a2; p++; } SimpleCursorAdapter simpleAdapter=new SimpleCursorAdapter(Xiaomu_Alldactor.this,R.layout.simple_item,cursor,new String[]{"d_head","d_dname","d_post","d_type","d_content"},new int[]{R.id.t1,R.id.t2,R.id.t3,R.id.t4,R.id.t5}); //设置适配器 list.setAdapter(simpleAdapter); //给ListView添加事件处理 list.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) { int cl=desc[i]; Intent intent=new Intent(Xiaomu_Alldactor.this,Xiaomu_Dactor.class); intent.putExtra("num",desc[i]-1); startActivity(intent); } }); } }

其中，R.layout.simple_item 是用于显示每个列表项的布局文件，new String[]{"d_head","d_dname","d_post","d_type","d_content"} 表示从数据源中获取哪些列的数据，其中 "d_head" 是列表项中头像的数据源列名...

package com.example.a7_1.DAO; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import com.example.a7_1.model.flag; import java.util.ArrayList; import java.util.List; public class FlagDao { private DBOpenHelper helper; private SQLiteDatabase db; public FlagDao (Context context){ helper = new DBOpenHelper(context) } public void add(flag flag){ db = helper.getWritableDatabase(); db.execSQL("insert into tb_flag (_id,flag) values (?,?)",new Object[]{ flag.getid(),flag.getFlag() }); } public void update(flag tb_flag){ db = helper.getWritableDatabase(); db.execSQL("update tb_flag set flag = ? where _id=?",new Object[]{ tb_flag.getFlag(), tb_flag.getid() } ); } public flag find(int id){ db = helper.getWritableDatabase(); Cursor cursor = db.rawQuery("select _id,flag from tb_flag where _id = ?",new String[]{String.valueOf(id)}); if(cursor.moveToNext()){ return new flag(cursor.getInt(cursor.getColumnIndex(("_id")),cursor.getString(cursor.getColumnIndex("flag"))); } return null; } public void delete(Integer... ids){ if(ids.length>0){ StringBuffer sb = new StringBuffer(); for (int i= 0; i<ids.length;i++){ sb.append('?').append(','); } sb.deleteCharAt(sb.length() -1); db = helper.getWritableDatabase(); db.execSQL("delete from tb_flag where _id in ("+ sb +")",(Object[]) ids); } } public List<flag> getScrollDate(int start,int count){ List<flag> lisTb_flags = new ArrayList<flag>(); db = helper.getWritableDatabase(); Cursor cursor = db.rawQuery("select * from tb_flag limit ?,?",new String[]{String.valueOf(start),String.valueOf(count)}); while (cursor.moveToNext()){ lisTb_flags.add(new flag(cursor.getInt(cursor.getColumnIndex("_id")),cursor.getString(cursor.getColumnIndex("flag")))); } return lisTb_flags; } public long getCount(){ db = helper.getWritableDatabase(); Cursor cursor = db.rawQuery("select count(_id) from tb_falg",null); if(cursor.moveToNext()){ return cursor.getLong(0); } return 0; } public int getMaxId(){ db = helper.getWritableDatabase(); Cursor cursor = db.rawQuery("select max(_id) from tb_falg",null); while (cursor.moveToNext()){ return cursor.getInt(0); } return 0; } }检查代码问题

return new flag(cursor.getInt(cursor.getColumnIndex("id")),cursor.getString(cursor.getColumnIndex("flag"))); 在第51行，tb_flag应该改为tb_flag，应该改为： db.execSQL("delete from tb_flag ...

@SuppressLint("Range") public SendFrameTimeMtc selectFrameTime(long sceneStartTime) { SendFrameTimeMtc sendFrameTimeMtc = new SendFrameTimeMtc(); Cursor cursor = mRDB.query(TABLE_FRAMETIME, null, "scene_start_time=?", new String[]{String.valueOf(sceneStartTime)}, null, null, "_id", null); int batch = 0; int curBatch = 0; long frameTime = 0; long curFrameTime = 0; if (cursor.getCount() > 0) { int batchIndex = cursor.getColumnIndex("batch"); int frameTimeIndex = cursor.getColumnIndex("frame_time"); SendFrameTimeEntity sendFrameTimeEntity = new SendFrameTimeEntity(); while (cursor.moveToNext()) { curFrameTime = cursor.getLong(frameTimeIndex); curBatch = cursor.getInt(batchIndex); if (sendFrameTimeEntity.getTs() == 0) { /** * 首次重置批次 */ sendFrameTimeEntity.setTs(curFrameTime); batch = curBatch; } else { if (batch == curBatch) { sendFrameTimeEntity.getFtList().add(curFrameTime - frameTime); frameTime = curFrameTime; } else { // 批次不同，重置 sendFrameTimeMtc.getSendFrames().add(sendFrameTimeEntity); sendFrameTimeEntity = new SendFrameTimeEntity(); sendFrameTimeEntity.setTs(curFrameTime); batch = curBatch; } } } sendFrameTimeMtc.getSendFrames().add(sendFrameTimeEntity); } return sendFrameTimeMtc; }

这段代码是一个方法，用于从数据库中查询某个场景的帧时间信息，并返回一个包含该场景所有帧时间的对象 SendFrameTimeMtc。该方法首先通过传入的场景开始时间，从数据库表 TABLE_FRAMETIME 中查询该场景的所有帧时间...

android获取外存音频资源播放.pdf

while (cursor.moveToNext()) { long id = cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media._ID)); String title = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.TITLE)); ...

while(cursor.moveToNext()) { int a2 = cursor.getInt(cursor.getColumnIndex("_id")); desc[p] = a2; p++; }

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