Android界面编程之八 各种杂项组件

此篇将介绍Android其他常用UI组件

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2.8.1 使用Toast显示提示信息框

Toast这个提示信息框用于向用户生成简单的提示信息，它有如下特点：

1.Toast 提示不会获得焦点

2.Toast提示会在一段时间后自动消失

使用Toast生成提示消息也非常简单，只要如下几个步骤：

1.调用Toast构造器或makeText()静态方法创建一个Toast对象

2.调用Toast的方法来设置该消息提示对齐方式、页边距等

3.调用Toast的show()方法将它显示出来

示例代码：

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout. activity_main );
        Button simple = (Button) findViewById(R.id. simple );
        simple.setOnClickListener( new OnClickListener()
        {
        @Override
        public void onClick(View source)
        {
        Toast toast = Toast.makeText(MainActivity. this , "simple hint" ,Toast. LENGTH_SHORT );
        toast.show();
        }
        });
        Button bn = (Button) findViewById(R.id. bn );
        bn.setOnClickListener( new OnClickListener()
        {
        @Override
        public void onClick(View source)
        {
        Toast toast = new Toast(MainActivity. this );
        toast.setGravity(Gravity. CENTER , 0, 0);
        ImageView image = new ImageView(MainActivity. this );
        image.setImageResource(R.drawable. tools );
        LinearLayout ll = new LinearLayout(MainActivity. this );
        ll.addView(image);
        TextView textView = new TextView(MainActivity. this );
        textView.setText( "hint with pic" );
        textView.setTextSize(20);
        ll.addView(textView);
        toast.setView(ll);

        toast.setDuration(Toast.LENGTH_LONG);

        toast.show();

        }

        });

    }

}

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2.8.2 CalendarView

可用于显示和选择日期；若希望监控该组件的日期改变，可调用CalendarView的setOnDateChangeListener()方法为此组件的点击时间添加事件监听器

android:dataTextAppearance
android:firstDayOfWeek
android:focusedMonthDateColor
android:maxDate
android:minDate
android:selectedDateVerticalBar
android:selectedWeekBackgroundColor
android:showWeekNumber
android:shownWeekCount		设置日历总共显示几个星期
android:unfocusedMonthDateColor
android:weekDayTextAppearance
android:weekNumberColor
android:weekSeparatorLineColor

示例代码：

main.xml

< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
    xmlns:tools = "http://schemas.android.com/tools"
    android:layout_width = "match_parent"
    android:layout_height = "match_parent"
    android:orientation = "vertical" >

    < TextView
        android:layout_width = "match_parent"
        android:layout_height = "wrap_content"
        android:text = "select your birthday" />
    < CalendarView
        android:layout_width = "match_parent"
        android:layout_height = "match_parent"
        android:firstDayOfWeek = "3"
        android:shownWeekCount = "4"
        android:selectedWeekBackgroundColor = "#aff"
        android:focusedMonthDateColor = "#f00"
        android:weekSeparatorLineColor = "#ff0"
        android:unfocusedMonthDateColor = "#f9f"
        android:id = "@+id/calendarView"         />

</ LinearLayout >

Java程序代码：

public class MainActivity extends ActionBarActivity {

CalendarView cv ;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout. activity_main );
        cv = (CalendarView) findViewById(R.id. calendarView );
        cv .setOnDateChangeListener( new OnDateChangeListener()
        {
        @Override
        public void onSelectedDayChange(CalendarView view, int year,
        int month, int dayOfMonth)
        {
        Toast.makeText(MainActivity. this , "your birthday is" + year + "." + month+ "." +dayOfMonth, Toast. LENGTH_SHORT ).show();
        }
        });

    }

}

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2.8.3 DatePicker和TimePicker

程序获取用户选择的日期、时间，可通过

为DatePicker添加OnDateChangedListener进行监听

为TimePicker添加OnTimerChangedListener进行监听

DatePicker支持的XML属性有

android:calendarViewShown	该日期选择是否显示CalendarView组件
android:endYear
android:maxDate
android:minDate
android:spinnerShown	该选择器是否显示Spinner日期选择组件
android:startYear

示例代码：

public class MainActivity extends Activity {

private int year ;
private int month ;
private int day ;
private int hour ;
private int minute ;

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout. activity_main );
        DatePicker datePicker = (DatePicker) findViewById(R.id. datePicker );
        TimePicker timePicker = (TimePicker) findViewById(R.id. timePicker );
        Calendar c = Calendar.getInstance();
        year = c.get(Calendar. YEAR );
        month = c.get(Calendar. MONTH );
        day = c.get(Calendar. DAY_OF_MONTH );
        hour = c.get(Calendar. HOUR );
        minute = c.get(Calendar. MINUTE );
        datePicker.init( year , month , day , new OnDateChangedListener()
        {
        @Override
        public void onDateChanged(DatePicker arg0, int year, int month, int day)
        {
        MainActivity. this . year = year;
        MainActivity. this . month = month;
        MainActivity. this . day = day;
        showDate(year, month, day, hour , minute );
        }
        });
//        timePicker.setOnTimeChangedListener(new onTimeChangedListener()
//        {
//        @Override
//        public void onTimeChanged(TimePicker view, int hourOfDay, int minute)
//        {
//        MainActivity.this.hour = hourOfDay;
//        MainActivity.this.minute = minute;
//        showDate(year, month, day, hour, minute);
//        }
//        });
    }

    private void showDate( int year, int month, int day, int hour, int minute)
    {
    EditText show = (EditText) findViewById(R.id. show );
    show.setText( "your purcharse day is " +year + "." +
    (month + 1) + "." + day + "  " + hour + ":" +minute);

    }

}

xml代码：

< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
    xmlns:tools = "http://schemas.android.com/tools"
    android:layout_width = "match_parent"
    android:layout_height = "match_parent"
    android:orientation = "vertical" >

    < TextView
        android:layout_width = "wrap_content"
        android:layout_height = "wrap_content"
        android:text = "time you buy the books"
        android:textSize = "20dp" />
    < DatePicker
        android:id = "@+id/datePicker"
        android:layout_width = "wrap_content"
        android:layout_height = "200dp"
        android:layout_gravity = "center_horizontal"
        android:startYear = "2000"
        android:endYear = "2012"
        android:calendarViewShown = "true"
        android:spinnersShown = "true" />
    < TimePicker
        android:id = "@+id/timePicker"
        android:layout_width = "wrap_content"
        android:layout_height = "100dp"
        android:layout_gravity = "center_horizontal"
        />
    < EditText
        android:id = "@+id/show"
        android:layout_width = "match_parent"
        android:layout_height = "wrap_content"
        android:editable = "false"
        android:cursorVisible = "false"
        />

</ LinearLayout >

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2.8.4 NumberPicker 

用户可通过拖动来选择数值。常用的方法如下：

setMinValue(int minVal)	设置该组件支持的最小值
setMaxValue(int maxVal)	设置该组件支持的最大值
setValue(int value)	设置该组件的当前值

示例代码：

public class MainActivity extends ActionBarActivity {

NumberPicker np1 , np2 ;
int minPrice = 25;
int maxPrice = 75;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout. activity_main );
        np1 = (NumberPicker) findViewById(R.id. np1 );
        np1 .setMinValue(10);
        np1 .setMaxValue(50);
        np1 .setValue( minPrice );
        np1 .setOnValueChangedListener( new OnValueChangeListener()
        {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal)
        {
        minPrice = newVal;
        showSelectedPrice();
        }
        });
        np2 = (NumberPicker) findViewById(R.id. np2 );
        np2 .setMinValue(60);
        np2 .setMaxValue(100);
        np2 .setValue( maxPrice );
        np2 .setOnValueChangedListener( new OnValueChangeListener()
        {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal)
        {
        maxPrice = newVal;
        showSelectedPrice();
        }
        });
    }
    public void showSelectedPrice()
    {
    Toast.makeText( this , "the lowest price you've choosen is" + minPrice
    + ", the highest price is" + maxPrice , Toast. LENGTH_SHORT ).show();

    }

}

main.xml代码：

< TableLayout xmlns:android = "http://schemas.android.com/apk/res/android"
    xmlns:tools = "http://schemas.android.com/tools"
    android:layout_width = "match_parent"
    android:layout_height = "match_parent" >

    < TableRow
        android:layout_width = "match_parent"
        android:layout_height = "wrap_content" >
    < TextView
        android:text = "choose low price"
        android:layout_width = "120dp"
        android:layout_height = "wrap_content" />
    < NumberPicker
        android:id = "@+id/np1"
        android:layout_width = "match_parent"
        android:layout_height = "80dp"
        android:focusable = "true"
        android:focusableInTouchMode = "true" />
    </ TableRow >
    < TableRow
        android:layout_width = "match_parent"
        android:layout_height = "wrap_content" >
    < TextView
        android:text = "choose high price"
        android:layout_width = "120dp"
        android:layout_height = "wrap_content" />
    < NumberPicker
        android:id = "@+id/np2"
        android:layout_width = "match_parent"
        android:layout_height = "80dp"
        android:focusable = "true"
        android:focusableInTouchMode = "true" />
    </ TableRow >

</ TableLayout >

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2.8.5 SearchView 

常用方法：

setIconifiedByDefault(boolean iconified)	设置该搜索框默认是否自动缩小为图标
setSubmitButtonEnable(boolean enabled)	设置是否显示搜索框
setQueryHint(CharSequence hint)
setOnQueryTextListener(SearchView.OnQueryTextListenter listener)	为该搜索框设置事件监听器

若为SearchView增加一个配套的ListView，则可以为SearchView增加自动完成功能

示例代码：

public class MainActivity extends Activity implements SearchView.OnQueryTextListener{

private SearchView sv ;
private ListView lv ;
private final String[] mStrings ={ "aaaaaa" , "bbbbbb" , "cccccc" };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout. activity_main );
        lv = (ListView) findViewById(R.id. lv );
        lv .setAdapter( new ArrayAdapter<String>( this ,android.R.layout. simple_list_item_1 , mStrings ));
        sv = (SearchView) findViewById(R.id. sv );
        sv .setIconifiedByDefault( false );
        sv .setOnQueryTextListener( this );
        sv .setSubmitButtonEnabled( true );
        sv .setQueryHint( "search" );
    }
    @Override
    public boolean onQueryTextChange(String newText)
    {
    if (TextUtils.isEmpty(newText))
    {
    lv .clearTextFilter();
    }
    else
    {
    lv .setFilterText(newText);
    }
    return true ;
    }
    @Override
    public boolean onQueryTextSubmit(String query)
    {
    Toast.makeText( this , "your choice is " +query, Toast. LENGTH_SHORT ).show();
    return false ;

    }

}

main.xml代码：

< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
    xmlns:tools = "http://schemas.android.com/tools"
    android:layout_width = "match_parent"
    android:layout_height = "match_parent"
    android:orientation = "vertical" >

    < SearchView
        android:id = "@+id/sv"
        android:layout_width = "wrap_content"
        android:layout_height = "wrap_content" />
    < ListView
        android:id = "@+id/lv"
        android:layout_width = "match_parent"
        android:layout_height = "0dp"
        android:layout_weight = "1" ></ ListView >

</ LinearLayout >

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2.8.6 TabHost

TabHost可以在窗口上放置多个标签，与TabWidget结合使用的还有如下组件：

TabWidget	代表选项卡的标签条
TabSpec	代表选项卡的一个Tab页面

TabHost仅仅是一个简单的容器，它提供了如下两个方法来创建、添加选项卡：

newTabSpec(String tag)	创建选项卡
addTab(TabHost.TabSpec tabSpec)	添加选项卡

使用TabHost的一般步骤如下：

1. 在布局界面中定义TabHost组件，并为该组件定义该选项卡内容
2. Activity应该继承TabActivity
3. 调用TabActivity的getTabHost()方法获取TabHost对象
4. 通过TabHost对象的方法来创建、添加选项卡

tips:若想监听，设置TabHost.OnTabChangeListener

TabHost使用时 main.xml中需要结合TabWidget使用，并且

TabHost	@android:id/tabhos
TabWidget	@android:id/tabs
FrameLayout	@android:id/tabcontent

上面3个ID是Android系统已有ID

示例代码:

main.xml

< TabHost xmlns:android = "http://schemas.android.com/apk/res/android"
    xmlns:tools = "http://schemas.android.com/tools"
    android:id = "@android:id/tabhost"
    android:layout_width = "match_parent"
    android:layout_height = "match_parent"
    android:layout_weight = "1" >
    < LinearLayout
        android:layout_width = "match_parent"
        android:layout_height = "match_parent"
        android:orientation = "vertical" >
        < TabWidget
            android:id = "@android:id/tabs"
        android:layout_width = "match_parent"
       android:layout_height = "wrap_content" />
        < FrameLayout
            android:id = "@android:id/tabcontent"
        android:layout_width = "match_parent"
        android:layout_height = "match_parent" >
            < LinearLayout
                android:id = "@+id/tab01"
                android:orientation = "vertical"
        android:layout_width = "match_parent"
        android:layout_height = "match_parent" >
                < TextView
        android:layout_width = "wrap_content"
        android:layout_height = "wrap_content"
        android:text = "testview" />
                < TextView
        android:layout_width = "wrap_content"
        android:layout_height = "wrap_content"
        android:text = "testview 2" />
            </ LinearLayout >
            < LinearLayout
                android:id = "@+id/tab02"
                android:orientation = "vertical"
        android:layout_width = "match_parent"
        android:layout_height = "match_parent" >
                < TextView
        android:layout_width = "wrap_content"
        android:layout_height = "wrap_content"
        android:text = "testview" />
                < TextView
        android:layout_width = "wrap_content"
        android:layout_height = "wrap_content"
        android:text = "testview 2" />
            </ LinearLayout >
            < LinearLayout
                android:id = "@+id/tab03"
                android:orientation = "vertical"
        android:layout_width = "match_parent"
        android:layout_height = "match_parent" >
                < TextView
        android:layout_width = "wrap_content"
        android:layout_height = "wrap_content"
        android:text = "testview" />
                < TextView
        android:layout_width = "wrap_content"
        android:layout_height = "wrap_content"
        android:text = "testview 2" />
            </ LinearLayout >
        </ FrameLayout >
           
    </ LinearLayout >

</ TabHost >

Java代码：

public class MainActivity extends TabActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout. activity_main );
        TabHost tabHost = getTabHost();
        TabSpec tab1 = tabHost.newTabSpec( "tab1" )
        .setIndicator( "Accepted" )
        .setContent(R.id. tab01 );
        tabHost.addTab(tab1);
        TabSpec tab2 = tabHost.newTabSpec( "tab2" )
        .setIndicator( "Called" ,getResources().getDrawable(R.drawable. ic_launcher ))
        .setContent(R.id. tab02 );
        tabHost.addTab(tab2);
        TabSpec tab3 = tabHost.newTabSpec( "tab3" )
        .setIndicator( "Missed" )
        .setContent(R.id. tab03 );
        tabHost.addTab(tab3);

    }

}

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2.8.7 ScrollView

由FrameLayout派生，作用是为普通组件添加滚动条，ScrollView只能包含一个组件。

ScrollView只能为应用添加垂直滚动条，若想添加水平滚动条，需借助HorizontalScrollView实现

示例代码：（TextView的内容必须使屏幕显示不下~~）

< ScrollView xmlns:android = "http://schemas.android.com/apk/res/android"
    xmlns:tools = "http://schemas.android.com/tools"
    android:layout_width = "match_parent"
    android:layout_height = "match_parent" >

    < HorizontalScrollView
        android:layout_width = "match_parent"
        android:layout_height = "wrap_content" >

        < LinearLayout
            android:layout_width = "match_parent"
            android:layout_height = "match_parent"
            android:orientation = "vertical" >

             <!—  众多TextView 定义省略 -->

        </ LinearLayout >
    </ HorizontalScrollView >

</ ScrollView >

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2.8.8 Notification

通知，即显示在手机状态栏的状态。Notification所代表的是一种具有全局效果的通知，程序一般通过NotificationManage服务来发送Notification

Android3.0 增加了Notification.Builder类，提供了如下常用方法

setDefaults()	设置通知LED灯、音乐、振动
setAutoCancel()	设置点击通知后，状态栏自动删除
setContentTitle()	设置通知图标
setContentText()	设置通知内容
setSmallIcon()	设置通知图标
setTick()	设置在状态栏的提示文本
setContentIntent()	设置点击通知后要启动的程序对应的PendingIntent

发送Notification的步骤如下：

1. 调用getSystemService(NOTIFICATION_SERVICE)方法获取系统的NotificationManager服务
2. 通过构造器设置各种属性
3. 为Notification设置各种属性
4. 通过NotificationManager发送Notification

示例代码：

public class MainActivity extends ActionBarActivity {

static final int NOTIFICATION_ID = 0X123;
NotificationManager nm ;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout. activity_main );
        nm = (NotificationManager)
        getSystemService( NOTIFICATION_SERVICE );
    }
    public void send(View source)
    {
    Intent intent = new Intent(MainActivity. this , OtherActivity. class );
    PendingIntent pi = PendingIntent.getActivity(MainActivity. this , 0, intent, 0);
    Notification notify = new Notification.Builder( this )
    .setAutoCancel( true )
    .setTicker( "MSG" )
    .setSmallIcon(R.drawable. ic_launcher )
    .setContentTitle( "a new message" )
    .setContentText( "congratulations, you have passed our test" )
//    .setDefault(Notification.DEFAULT_SOUND)
//    .setSound()
    .setWhen(System.currentTimeMillis())
    .setContentIntent(pi)
    .build();
    nm .notify( NOTIFICATION_ID , notify);
    }
    public void del(View v)
    {
    nm .cancel( NOTIFICATION_ID );

    }

}

main.xml代码：

<? xml version = "1.0" encoding = "utf-8" ?>
< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
android:orientation = "horizontal"
android:layout_width = "fill_parent"
android:layout_height = "fill_parent"
android:gravity = "center_horizontal"
>
< Button
android:layout_width = "wrap_content"
android:layout_height = "wrap_content"
android:text = "发送Notification"
android:onClick = "send"
/>
< Button
android:layout_width = "wrap_content"
android:layout_height = "wrap_content"
android:text = "删除Notification"
android:onClick = "del"
/>
</ LinearLayout >