Android 2.2新增Widget之ProtipWidget源碼

 在android 2.2 SDK中我們可能首次啟動模擬器可以看到和以前不一樣的是多出了一個綠色的小機器人提示信息，Google給我們了演示了android中如何通過RemoteVIEw和簡單的圖片輪換方式實現動畫效果在桌面小工具中，appWidget的基類時AppWidgetProvider類，不過Widget本身的生命周期管理並非Activity，相對於的而是BroadcastReceiver廣播方式處理的，android 2.2新增的Widget的實現大家可以從中學習到很多有用的知識。

public class ProtipWidget extends AppWidgetProvider {
public static final String ACTION_NEXT_TIP = "com.android.misterwidget.NEXT_TIP"; //定義action切換到下一條提示
public static final String ACTION_POKE = "com.android.misterwidget.HEE_HEE"; //喚醒小機器人

public static final String EXTRA_TIMES = "times";

public static final String PREFS_NAME = "Protips";
public static final String PREFS_TIP_NUMBER = "widget_tip";

private static Random sRNG = new Random(); //輪換圖片用到的，生成一個靜態的隨機數生成器

private static final Pattern sNewlineRegex = Pattern.compile(" *\\n *");
private static final Pattern sDrawableRegex = Pattern.compile(" *@(drawable/[a-z0-9_]+) *");

// 初始化時Droid是眼睛沒有睜開，同時沒有信息提示
private int mIconRes = R.drawable.droidman_open;
private int mMessage = 0;

private AppWidgetManager mWidgetManager = null;
private int[] mWidgetIds;
private Context mContext;

private CharSequence[] mTips;

private void setup(Context context) {
mContext = context;
mWidgetManager = AppWidgetManager.getInstance(context);
mWidgetIds = mWidgetManager.getAppWidgetIds(new ComponentName(context, ProtipWidget.class));

SharedPreferences pref = context.getSharedPreferences(PREFS_NAME, 0);
mMessage = pref.getInt(PREFS_TIP_NUMBER, 0);

mTips = context.getResources().getTextArray(R.array.tips);

if (mTips != null) {
if (mMessage >= mTips.length) mMessage = 0;
} else {
mMessage = -1;
}

}

public void goodmorning() { //android開發網提示線程中輪換圖片，使用了500，200，100等這樣的0.5秒休眠，0.2秒休眠實現了動畫的間隔效果
mMessage = -1;
try {
setIcon(R.drawable.droidman_down_closed);
Thread.sleep(500);
setIcon(R.drawable.droidman_down_open);
Thread.sleep(200);
setIcon(R.drawable.droidman_down_closed);
Thread.sleep(100);
setIcon(R.drawable.droidman_down_open);
Thread.sleep(600);
} catch (InterruptedException ex) {
}
mMessage = 0;
mIconRes = R.drawable.droidman_open;
refresh();
}

@Override
public void onReceive(Context context, Intent intent) { //上面android123已經講到了，appWidget是基於broadcastreceiver類的，所以說需要響應onReceive通過action來驅動事件。
setup(context);

if (intent.getAction().equals(ACTION_NEXT_TIP)) {
mMessage = getNextMessageIndex();
SharedPreferences.Editor pref = context.getSharedPreferences(PREFS_NAME, 0).edit();
pref.putInt(PREFS_TIP_NUMBER, mMessage);
pref.commit();
refresh();
} else if (intent.getAction().equals(ACTION_POKE)) {
blink(intent.getIntExtra(EXTRA_TIMES, 1));
} else if (intent.getAction().equals(AppWidgetManager.ACTION_APPWIDGET_ENABLED)) {
goodmorning();
} else {
mIconRes = R.drawable.droidman_open;
refresh();
}
}

private void refresh() { //管理如果有多個本widget執行需要逐個更新
RemoteVIEws rv = buildUpdate(mContext);
for (int i : mWidgetIds) {
mWidgetManager.updateAppWidget(i, rv);
}
}

private void setIcon(int resId) {
mIconRes = resId;
refresh();
}

private int getNextMessageIndex() {
return (mMessage + 1) % mTips.length;
}

private void blink(int blinks) {
if (mMessage < 0) return;

//android123提示大家比較有意思的就是小綠人眼睛的一開一閉，這裡使用的是圖片輪換方式來實現動畫效果，在appWidget中我們可以用的控件十分少

setIcon(R.drawable.droidman_closed);
try {
Thread.sleep(100);
while (0<--blinks) {
setIcon(R.drawable.droidman_open);
Thread.sleep(200);
setIcon(R.drawable.droidman_closed);
Thread.sleep(100);
}
} catch (InterruptedException ex) { }
setIcon(R.drawable.droidman_open);
}

public RemoteVIEws buildUpdate(Context context) {
RemoteViews updateViews = new RemoteVIEws(
context.getPackageName(), R.layout.widget); //映射布局，widget.XML文件的源碼在下面可以找到

// 按下bubble的事件,對應action_next_tip動作
Intent bcast = new Intent(context, ProtipWidget.class);
bcast.setAction(ACTION_NEXT_TIP);
PendingIntent pending = PendingIntent.getBroadcast(
context, 0, bcast, PendingIntent.FLAG_UPDATE_CURRENT);
updateVIEws.setOnClickPendingIntent(R.id.tip_bubble, pending);

//這裡為action_poke
bcast = new Intent(context, ProtipWidget.class);
bcast.setAction(ACTION_POKE);
bcast.putExtra(EXTRA_TIMES, 1);
pending = PendingIntent.getBroadcast(
context, 0, bcast, PendingIntent.FLAG_UPDATE_CURRENT);
updateVIEws.setOnClickPendingIntent(R.id.bugdroid, pending);

// Tip bubble text
if (mMessage >= 0) {
String[] parts = sNewlineRegex.split(mTips[mMessage], 2);
String title = parts[0];
String text = parts.length > 1 ? parts[1] : "";

// Look for a callout graphic referenced in the text
Matcher m = sDrawableRegex.matcher(text);
if (m.find()) {
String imageName = m.group(1);
int resId = context.getResources().getIdentifIEr(

imageName, null, context.getPackageName());
updateViews.setImageVIEwResource(R.id.tip_callout, resId);
updateViews.setViewVisibility(R.id.tip_callout, VIEw.VISIBLE);
text = m.replaceFirst("");
} else {
updateViews.setImageVIEwResource(R.id.tip_callout, 0);
updateViews.setViewVisibility(R.id.tip_callout, VIEw.GONE);
}

updateViews.setTextVIEwText(R.id.tip_message,
text);
updateViews.setTextVIEwText(R.id.tip_header,
title);
updateViews.setTextVIEwText(R.id.tip_footer,
context.getResources().getString(
R.string.pager_footer,
(1+mMessage), mTips.length));
updateViews.setViewVisibility(R.id.tip_bubble, VIEw.VISIBLE);
} else {
updateViews.setViewVisibility(R.id.tip_bubble, VIEw.INVISIBLE);
}

updateViews.setImageVIEwResource(R.id.bugdroid, mIconRes);

return updateVIEws;
}
}

有關androidManifest.XML中詳細的recevIEr代碼如下

<receiver android:name=".ProtipWidget" android:label="@string/widget_name">
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
<action android:name="com.android.protips.NEXT_TIP" />
<action android:name="com.android.protips.HEE_HEE" />
</intent-filter>
<meta-data android:name="android.appwidget.provider" android:resource="@XML/widget_build" />
</receiver>

有關res/xml/widget_build.XML的代碼如下

<appwidget-provider XMLns:android="http://schemas.android.com/apk/res/android"
android:minWidth="294dip"
android:minHeight="72dip"
android:updatePeriodMillis="0"
android:initialLayout="@layout/widget" />

有關res/layout/widget.XML的代碼如下，注意下面使用了布局文件套嵌的include方式

<RelativeLayout XMLns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/widget"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orIEntation="vertical"
android:padding="5dip"
>

<include layout="@layout/droid" />
<include layout="@layout/bubble" />
</RelativeLayout>

有關res/layout/droid.XML的代碼如下

<ImageVIEw XMLns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/bugdroid"
android:src="@drawable/droidman_down_closed"
android:scaleType="center"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
/>

有關res/layout/bubble.XML的代碼如下

<RelativeLayout XMLns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/tip_bubble"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_toLeftOf="@+id/bugdroid"
android:layout_centerVertical="true"
android:gravity="center_vertical|left"
android:layout_marginRight="2dip"
android:visibility="invisible"
android:background="@drawable/droid_widget"
android:focusable="true"
>
<TextVIEw
android:layout_width="0dip"
android:layout_height="0dip"
android:layout_alignParentTop="true"
android:layout_marginTop="-100dip"
android:text="@string/widget_name"
/>
<TextVIEw
android:layout_width="0dip"
android:layout_height="0dip"
android:layout_alignParentTop="true"
android:layout_marginTop="-90dip"
android:text="@string/tts_pause"
/>
<TextVIEw
android:id="@+id/tip_footer"
style="@style/TipText.Footer"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginRight="1dip"
/>
<ImageVIEw
android:id="@+id/tip_callout"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:gravity="center"
android:layout_alignParentTop="true"
android:layout_alignParentRight="true"
android:layout_above="@id/tip_footer"
android:visibility="gone"
android:padding="4dip"
/>
<TextVIEw
android:id="@+id/tip_header"
style="@style/TipText.Header"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_toLeftOf="@id/tip_callout"
android:layout_alignWithParentIfMissing="true"
android:layout_marginTop="0dip"
android:layout_marginLeft="3dip"
/>
<TextVIEw
android:id="@+id/tip_message"
style="@style/TipText.Message"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="@id/tip_header"
android:layout_alignLeft="@id/tip_header"
android:layout_alignRight="@id/tip_header"
android:layout_marginTop="1dip"
/>
</RelativeLayout>

有關上面bubble.XML中的drawable對象droid_widget的代碼如下

<selector XMLns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" android:drawable="@drawable/droid_widget_pressed" />
<item android:state_focused="true" android:state_window_focused="true" android:drawable="@drawable/droid_widget_focused" />
<item android:state_focused="true" android:state_window_focused="false" android:drawable="@drawable/droid_widget_normal" />
<item android:drawable="@drawable/droid_widget_normal" />
</selector>