1.SQLite
?
创建数据库
Android 不自动提供数据库。在 Android 应用程序中使用 SQLite，必须自己创建数据库，然后创建表、索引，填充数据。Android 提供了 SQLiteOpenHelper 帮助你创建一个数据库，你只要继承 SQLiteOpenHelper 类，就可以轻松的创建数据库。SQLiteOpenHelper 类根据开发应用程序的需要，封装了创建和更新数据库使用的逻辑。SQLiteOpenHelper 的子类，至少需要实现三个方法：
- 构造函数，调用父类 SQLiteOpenHelper 的构造函数。这个方法需要四个参数：上下文环境（例如，一个 Activity），数据库名字，一个可选的游标工厂（通常是 Null），一个代表你正在使用的数据库模型版本的整数。
- onCreate（）方法，它需要一个 SQLiteDatabase 对象作为参数，根据需要对这个对象填充表和初始化数据。
- onUpgrage() 方法，它需要三个参数，一个 SQLiteDatabase 对象，一个旧的版本号和一个新的版本号，这样你就可以清楚如何把一个数据库从旧的模型转变到新的模型。
SQLiteOpenHelper 的子类调用 getReadableDatabase() 或 getWriteableDatabase() 方法，你可以得到 SQLiteDatabase 实例。
使用SQLiteDatabase 对象的 insert(), update(), delete()，rawQuery/query 方法，进行增删改查。
Cursor---查询结果集
?
用StringBuilder写Sql
例：? ??? StringBuilder selectBuilder = new StringBuilder();
??? ??? selectBuilder.append("select * from ").append(DBHelper.TABLE_NAME).append(" where ")
??? ??? .append(DBHelper.COLUMN_DATE).append(" =?").append(" order by ").append(DBHelper.COLUMN_TYPE);
2.AlertDialog
new AlertDialog.Builder(this)
??? ??? .setTitle("请选择")
??? ??? .setIcon(android.R.drawable.ic_dialog_info)?????????????
??? ??? .setSingleChoiceItems(new String[] {"选项1","选项2","选项3","选项4"}, 0,
??? ??? ? new DialogInterface.OnClickListener() {
??? ??? ???? public void onClick(DialogInterface dialog, int which) {
??? ??? ??????? dialog.dismiss();
??? ??? ???? }
??? ??? ? }
??? ??? )
??????? .setPositiveButton("确定", new DialogInterface.OnClickListener(){
???
??? ??? ??? ??? ??? ??? @Override
??? ??? ??? ??? ??? ??? public void onClick(DialogInterface dialog, int which)
??? ??? ??? ??? ??? ??? {
??? ??? ??? ??? ??? ??? ???
??? ??? ??? ??? ??? ??? }
??? ??? ??? ??? ??? })
??? ??? .setNegativeButton("取消", null)
??? ??? .setNeutralButton("Neutral2", new DialogInterface.OnClickListener() {
??? ??? ???
??? ??? ??? @Override
??? ??? ??? public void onClick(DialogInterface arg0, int arg1) {
??? ??? ??? ??? // TODO Auto-generated method stub
??? ??? ??? ??? arg0.cancel();
??? ??? ??? }
??? ??? })
??? ??? .show();
?
3.Toast
Toast.makeText( ToastActivity.this,“hello”,Toast.LENGTH_LONG).show();
?
4.spinner
spinner = (Spinner) findViewById(R.id.spinType);
spinner.setAdapter(adapter);
//给弹出的选择框加一个标题
spinner.setPrompt("选择类型");
?
其中adapter：
adapter=new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, String[] );
或adapter=new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, ArrayList<String>);
或adapter=new ArrayAdapter<MyEnum>(this,android.R.layout.simple_spinner_item;
adapter.add(MyEnum.xxx);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
?
ArrayList<String>形式的adapter，可以动态删减下拉框中的内容，adapter.add,adapter.remove
5.Menu
??? ??? @Override
??? ??? public boolean onCreateOptionsMenu(Menu menu) {
??? ??? ??? // TODO Auto-generated method stub
??? ??? ??? /*添加三个菜单项目，并设置图片*/
??? ??? ??? menu.add(0, 1, 1, "Edit").setIcon(android.R.drawable.ic_menu_edit);
??? ??? ??? menu.add(0, 2, 2, "Open").setIcon(android.R.drawable.ic_menu_agenda);
??? ??? ??? menu.add(0, 3, 3, "Exit").setIcon(android.R.drawable.ic_lock_power_off);
??? ??? ??? return super.onCreateOptionsMenu(menu);
??? ??? }
??? ??? @Override
??? ??? public boolean onOptionsItemSelected(MenuItem item) {
??? ??? ??? // TODO Auto-generated method stub
??? ??? ??? switch (item.getItemId()) {
??? ??? ??? case 1:
??? ??? ??? /*显示main.xml为主屏布局*/
??? ??? ??? setLayoutShow(R.layout.main);
??? ??? ?
??? ??? ??? NoteDebug("编辑文件Layout");
??? ??? ??? break;
??? ??? ??? case 2:
??? ??? ??? /*显示open.xml为主屏布局*/
??? ??? ??? setLayoutShow(R.layout.open);
??? ??? ???
??? ??? ??? NoteDebug( "打开文件Layout");
??? ??? ??? break;
??? ??? ??? case 3:
??? ??? ??? /*退出*/
??? ??? ??? finish();
??? ??? ??? NoteDebug( "Byebye");
??? ??? ??? break;
??? ??? ??? default:
??? ??? ??? break;
??? ??? ??? }
??? ??? ??? return super.onOptionsItemSelected(item);
??? ??? }
??? ???
??? ??? private void NoteDebug(String showString){
??? ??? ??? /*显示Toast提示*/
??? ??? ??? Toast.makeText(this,showString, Toast.LENGTH_SHORT ).show();
??? ??? }
?
------------------
?? MenuItem exit,testItem;
??? public boolean onCreateOptionsMenu(Menu menu) {
??? ??? // TODO Auto-generated method stub
??? ??? /*添加退出菜单*/
??? ??? exit=menu.add("Exit");
??? ??? /*设置退出菜单图片*/
??? ??? exit.setIcon(android.R.drawable.ic_menu_close_clear_cancel );
??? ???
??? ??? testMenuItem = menu.add("testItem");
??? ??? testMenuItem.setIcon(android.R.drawable.ic_menu_call);
??? ??? return super.onCreateOptionsMenu(menu);
??? }
??? @Override
??? public boolean onOptionsItemSelected(MenuItem item) {
??? ??? // TODO Auto-generated method stub
??? ??? /*结束Activity*/
??? ??? if(item.equals(exit)){
??? ??? ??? finish();
??? ??? ???
??? ??? }
??? ??? else if(item.equals(testMenuItem)){
??? ??? ??? Toast.makeText(this, "test menuitem is clicked", Toast.LENGTH_LONG).show();
??? ??? }
??? ???
??? ??? return super.onOptionsItemSelected(item);
??? }
?
6.TabView
private TabHost tabHost;
?
tabHost = getTabHost();
tabHost.addTab(tabHost.newTabSpec("today").setIndicator("今日账单",getResources().getDrawable(R.drawable.tab_today))
??? ??? ??? ??? .setContent(new Intent(this,Today.class)
??? ??? ??? ??? //刷新
??? ??? ??? ??? .addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)));
?
tabHost.addTab(tabHost.newTabSpec("history").setIndicator("历史账单",getResources().getDrawable(R.drawable.tab_history))
??? ??? ??? ??? .setContent(new Intent(this,History.class)));
tabHost.setOnTabChangedListener(this);
?
??? @Override
??? public void onTabChanged(String tabId) {
??? ??? if(tabId.equals("history"))
??? ??? {
??? ??? ??? Intent intent = new Intent(this,SelectDate.class);
??? ??? ??? startActivityForResult(intent, REQUEST_QUERYDATE);
??? ??? }
??? }
?
7.日期、日历
??? ??? Calendar calendar = Calendar.getInstance();
??? ??? DateFormat format = new SimpleDateFormat("yyyy-MM-dd");
??? ??? String today = format.format(calendar.getTime());
?
8.ListView
String []name=new String[]{"Java","C++","C","C#","VB","XML",".NET","J#"};
ArrayAdapter<String> arrayadapter =new ArrayAdapter<String>(this,
??????? android.R.layout.simple_list_item_1,name);
?
listview = (ListView)findViewById(R.id.list);
listview.setAdapter(arrayadapter);
listview.setOnItemClickListener(this);
------复杂点的
listview.setAdapter(new ListItemAdapter(this));
class ListItemAdapter extends BaseAdapter
??? {}；
this.layoutInflater = LayoutInflater.from(context);
view=layoutInflater.inflate(R.layout.listview_item, null);----inflate一个新的布局
9.Html.fromHtml
Spanned spannable = Html.fromHtml("the google url: " +
??????????????? "<a href=\"http://www.google.com\">http://www.google.com</a><br/>" +
??????????????? "the telephone: " +
??????????????? "<a href=\"tel:18603045201\">18603045201</a>"
??????????????? );
?
textview.setText(spannable);
textview.setMovementMethod(LinkMovementMethod.getInstance());//点击链接可以直接访问网页或者打电话
?
SpannableString ss=
??????????? new SpannableString("the google url: http://www.google.com 18600000001");
??????? ss.setSpan(new URLSpan("http://www.google.com"),
??????????????? 16, 37, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
??????? ss.setSpan(new URLSpan("tel:18603045201"),
??????????????? 38, 49, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
textview.setText(ss);
textview.setMovementMethod(LinkMovementMethod.getInstance());
?