填充用sql数据库项目列表视图

本文介绍了填充用sql数据库项目列表视图的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我的申请是基于当用户输入了添加类别按钮显示对话框。然后，它应该将数据保存到一个SQL数据库和填充用户添加了每个项目的列表视图。我选择了SQL数据库，因为我希望当用户结束应用程序中的数据进行保存。我怎么居然填充的项目列表视图？以下是我迄今为止：

公共类CategoryDatabase {公共静态最后弦乐KEY_ROWID =_id;公共静态最后弦乐KEY_CATEGORY =类别;私有静态最后弦乐DATABASE_NAME =DBCategory;私有静态最后弦乐DATABASE_TABLE =categoryTable;私有静态最终诠释DATABASE_VERSION = 1;私人DbHelper ourHelper;私人最终上下文ourContext;私人SQLiteDatabase ourDatabase;公共CategoryDatabase（上下文C）{    ourContext = C;}公共CategoryDatabase的open（）抛出的SQLException {    ourHelper =新DbHelper（ourContext）;    ourDatabase = ourHelper.getWritableDatabase（）;    返回此;}公共无效的close（）{    ourHelper.close（）;}私有静态类DbHelper扩展SQLiteOpenHelper {    公共DbHelper（上下文的背景下）{        超（背景下，DATABASE_NAME，空，DATABASE_VERSION）;        // TODO自动生成构造函数存根    }    @覆盖    公共无效的onCreate（SQLiteDatabase DB）{        db.execSQL（CREATE TABLE+ DATABASE_TABLE +（+                KEY_ROWID +INTEGER PRIMARY KEY AUTOINCREMENT，+                KEY_CATEGORY +TEXT NOT NULL）;        ）;    }    @覆盖    公共无效onUpgrade（SQLiteDatabase分贝，INT oldVersion，诠释静态网页）{        db.execSQL（DROP TABLE IF EXISTS+ DATABASE_TABLE）;        的onCreate（DB）;    }}众长createEntry（串类）{    ContentValues​​ CV =新ContentValues​​（）;    cv.put（KEY_CATEGORY，类别）;    返回ourDatabase.insert（DATABASE_TABLE，空，CV）;}}

和主要活动：

公共类MainActivity延伸活动{最后上下文的背景下=这;ArrayAdapter＆LT;串GT; arrayAdapter;ArrayList的＆LT;串GT;时listItems =新的ArrayList＆LT;串GT;（）;LV的ListView;@覆盖保护无效的onCreate（捆绑savedInstanceState）{    super.onCreate（savedInstanceState）;    的setContentView（R.layout.main）;    LV =（ListView控件）findViewById（R.id.listView1）;    arrayAdapter =新ArrayAdapter＆LT;串GT;（这一点，android.R.layout.simple_list_item_1，listItems中）;    lv.setAdapter（arrayAdapter）;}@覆盖公共布尔onCreateOptionsMenu（菜单菜单）{    //充气菜单;如果是present这增加了项目操作栏。    。getMenuInflater（）膨胀（R.menu.main，菜单）;    返回true;}@覆盖公共布尔onOptionsItemSelected（菜单项项）{    开关（item.getItemId（））{    案例R.id.menu_add_cat：        LayoutInflater李= LayoutInflater.from（背景）;        查看promptAdd = li.inflate（R.layout.prompt_add，NULL）;        AlertDialog.Builder alertDialogBu​​ilder =新AlertDialog.Builder（背景）;        //设置prompts.xml到alertDialogBu​​ilder        alertDialogBu​​ilder.setView（promptAdd）;        最终的EditText etAddCat =（EditText上）promptAdd.findViewById（R.id.etDialogInput）;        //设置对话框消息        alertDialogBu​​ilder.setPositiveButton（完成，新DialogInterface.OnClickListener（）{            @覆盖            公共无效的onClick（DialogInterface对话，诠释它）{            / *             *添加一个这里的猫             *如果（空=输入和放大器;！＆安培; input.length（）0）{                    listItems.add（输入）;                    arrayAdapter.notifyDataSetChanged（）;                }其他{                    Toast.makeText（getApplicationContext（），请输入一个新的类别，Toast.LENGTH_LONG）.show（）;                }             * /                布尔didItWork = TRUE;                尝试{                    串类= etAddCat.getText（）的toString（）。                    CategoryDatabase进入=新CategoryDatabase（MainActivity.this）;                    entry.open（）;                    entry.createEntry（类）;                    entry.close（）;                }赶上（例外五）{                    didItWork = FALSE;                    字符串错误= e.toString（）;                    对话D =新的对话框（MainActivity.this）;                    d.setTitle（该死！）;                    TextView的电视=新的TextView（MainActivity.this）;                    tv.setText（错误）;                    d.setContentView（电视）;                    d.show（）;                }最后{                    如果（didItWork）{                        对话D =新的对话框（MainActivity.this）;                        d.setTitle（见鬼啊！）;                        TextView的电视=新的TextView（MainActivity.this）;                        tv.setText（成功）;                        d.setContentView（电视）;                        d.show（）;                    }                }            }        }）        .setNegativeButton（取消，新DialogInterface.OnClickListener（）{            @覆盖            公共无效的onClick（DialogInterface对话，诠释它）{                dialog.cancel（）;            }        }）;        //创建警报对话框        AlertDialog alertDialog = alertDialogBu​​ilder.create（）;        // 展示下        alertDialog.show（）;        打破;    }    //返回super.onOptionsItemSelected（项目）;    返回true;}} // MainActivity结束

解决方案

创建一个函数 getAllCategory（）在 CategoryDatabase 类。

公开名单＆LT;串GT; getAllCategory（）{    清单＆LT;串GT;表=新的ArrayList＆LT;串GT;（）;    //选择所有查询    字符串selectQuery =SELECT * FROM+ DATABASE_TABLE;    光标光标= ourDatabase.rawQuery（selectQuery，NULL）;    //通过所有行循环，并增加列表    如果（cursor.moveToFirst（））{        做{            List.add（cursor.getString（1））;        }而（cursor.moveToNext（））;    }    返回列表;   }

要填充项目的ListView。

在你的 MainActivity 说上按一下按钮。

CategoryDatabase进入=新CategoryDatabase（MainActivity.this）;            entry.open（）;            清单＆LT;串GT;所有= entry.getAllCategory（）;            LV =（ListView控件）findViewById（R.id.listView1）;            arrayAdapter =新ArrayAdapter＆LT;串GT;（MainActivity.this，android.R.layout.simple_list_item_1，全部）;            lv.setAdapter（arrayAdapter）;

编辑：

在的onCreate

CategoryDatabase进入=新CategoryDatabase（MainActivity.this）;            entry.open（）;            清单＆LT;串GT;所有= entry.getAllCategory（）;                如果（all.size（）0）//检查列表中包含的项目。                {            LV =（ListView控件）findViewById（R.id.listView1）;            arrayAdapter =新ArrayAdapter＆LT;串GT;（MainActivity.this，android.R.layout.simple_list_item_1，全部）;            lv.setAdapter（arrayAdapter）;                }                其他                {                   Toast.makeText（MainActivity.this，没有条款显示，1000）.show（）;                }

My application is based on displaying a dialog box when the user enters the "add category" button. It then should save data into an SQL Database and populate a list view with each item the user adds. I chose SQL database because I want the data to be saved when the user ends the app. How do I actually populate the list view with those items ? Here is what I have so far:

public class CategoryDatabase { public static final String KEY_ROWID = "_id"; public static final String KEY_CATEGORY = "category"; private static final String DATABASE_NAME = "DBCategory"; private static final String DATABASE_TABLE = "categoryTable"; private static final int DATABASE_VERSION = 1; private DbHelper ourHelper; private final Context ourContext; private SQLiteDatabase ourDatabase; public CategoryDatabase(Context c){ ourContext = c; } public CategoryDatabase open() throws SQLException{ ourHelper = new DbHelper(ourContext); ourDatabase = ourHelper.getWritableDatabase(); return this; } public void close(){ ourHelper.close(); } private static class DbHelper extends SQLiteOpenHelper{ public DbHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); // TODO Auto-generated constructor stub } @Override public void onCreate(SQLiteDatabase db) { db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" + KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_CATEGORY + " TEXT NOT NULL);" ); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE); onCreate(db); } } public long createEntry(String category) { ContentValues cv = new ContentValues(); cv.put(KEY_CATEGORY, category); return ourDatabase.insert(DATABASE_TABLE, null, cv); } }

and the Main Activity:

public class MainActivity extends Activity { final Context context = this; ArrayAdapter<String> arrayAdapter; ArrayList<String> listItems = new ArrayList<String>(); ListView lv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); lv = (ListView)findViewById(R.id.listView1); arrayAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, listItems); lv.setAdapter(arrayAdapter); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { switch(item.getItemId()){ case R.id.menu_add_cat: LayoutInflater li = LayoutInflater.from(context); View promptAdd = li.inflate(R.layout.prompt_add, null); AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context); //set prompts.xml to alertDialogBuilder alertDialogBuilder.setView(promptAdd); final EditText etAddCat = (EditText)promptAdd.findViewById(R.id.etDialogInput); //set a dialog message alertDialogBuilder.setPositiveButton("Done", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { /* * add a cat here * if(null != input && input.length() > 0){ listItems.add(input); arrayAdapter.notifyDataSetChanged(); }else{ Toast.makeText(getApplicationContext(), "Please enter a new category", Toast.LENGTH_LONG).show(); } */ boolean didItWork = true; try{ String category = etAddCat.getText().toString(); CategoryDatabase entry = new CategoryDatabase(MainActivity.this); entry.open(); entry.createEntry(category); entry.close(); }catch(Exception e){ didItWork = false; String error = e.toString(); Dialog d = new Dialog(MainActivity.this); d.setTitle("Dang it ! "); TextView tv = new TextView(MainActivity.this); tv.setText(error); d.setContentView(tv); d.show(); }finally{ if(didItWork){ Dialog d = new Dialog(MainActivity.this); d.setTitle("Heck yea ! "); TextView tv = new TextView(MainActivity.this); tv.setText("Success"); d.setContentView(tv); d.show(); } } } }) .setNegativeButton("Cancel", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.cancel(); } }); // create alert dialog AlertDialog alertDialog = alertDialogBuilder.create(); // show it alertDialog.show(); break; } //return super.onOptionsItemSelected(item); return true; } }// end of MainActivity

解决方案

Create a function getAllCategory() in CategoryDatabase class.

public List<String> getAllCategory() { List<String> List = new ArrayList<String>(); // Select All Query String selectQuery = "SELECT * FROM " + DATABASE_TABLE; Cursor cursor = ourDatabase.rawQuery(selectQuery, null); // looping through all rows and adding to list if (cursor.moveToFirst()) { do { List.add(cursor.getString(1)); } while (cursor.moveToNext()); } return List; }

To populate items to listview.

In your MainActivity say on button click.

CategoryDatabase entry = new CategoryDatabase(MainActivity.this); entry.open(); List<String> all = entry.getAllCategory(); lv = (ListView)findViewById(R.id.listView1); arrayAdapter = new ArrayAdapter<String>(MainActivity.this,android.R.layout.simple_list_item_1, all); lv.setAdapter(arrayAdapter);

Edit :

In onCreate

CategoryDatabase entry = new CategoryDatabase(MainActivity.this); entry.open(); List<String> all = entry.getAllCategory(); if(all.size()>0) // check if list contains items. { lv = (ListView)findViewById(R.id.listView1); arrayAdapter = new ArrayAdapter<String>(MainActivity.this,android.R.layout.simple_list_item_1, all); lv.setAdapter(arrayAdapter); } else { Toast.makeText(MainActivity.this,"No items to display",1000).show(); }