AppWidget学习总结

一.创建AppWidget.
    1.在res/xml下创建一个xml文件,以设置widget占用的空间等信息.如widget_provider.xml
        <?xml version="1.0" encoding="utf-8"?>
        <appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
            android:minWidth="180dp"
            android:minHeight="20dp"
            android:updatePeriodMillis="1000"
            android:initialLayout="@layout/widget_main" >
        </appwidget-provider>
       
        属性说明
        android:minWidth 指定widget占用的宽度
        android:minHeight　指定widget占用的高度
        android:updatePeriodMillis　定义Widget的更新频率, Android框架每隔一段时间, 会回调AppWidgetProvider类的onUpdate()事件；
                                    以毫秒为单位, 更新时间为30～60分钟, 如果设定30分钟以内无作用.
        android:initialLayout 指定Widget的布局文件, 一般将此文件放到res/layout下.
   
    2.实现布局文件,如widget_main.xml

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:background="#4555" >

    <TextView

        android:id="@+id/mTvDate"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:gravity="center_horizontal"

        android:singleLine="true"

        android:textColor="#f00"

        android:textSize="18sp" />

    <ProgressBar

        android:id="@+id/mProgressBar"

        style="?android:attr/progressBarStyleHorizontal"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_below="@id/mTvDate" />

    <LinearLayout

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentBottom="true"

        android:layout_centerHorizontal="true" >

        <TextView

            android:id="@+id/mBtnHour"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:singleLine="true"

            android:text="@string/hour_24"

            android:textColor="#e00"

            android:textSize="18sp" />

    </LinearLayout>

</RelativeLayout>

3.实现业务逻辑类,该类继承自AppWidgetProvider.

package com.ahai.hellowidget;

import static com.ahai.util.DebugMessage.d;

import java.text.SimpleDateFormat;

import java.util.Date;

import android.annotation.SuppressLint;

import android.app.PendingIntent;

import android.appwidget.AppWidgetManager;

import android.appwidget.AppWidgetProvider;

import android.content.ComponentName;

import android.content.Context;

import android.content.Intent;

import android.os.Bundle;

import android.os.Handler;

import android.widget.RemoteViews;

public class DateWidgetProvider extends AppWidgetProvider implements WidgetUpdateTask.Callbacks {

    public static final String ACTION_REMOTE_CLICK_UPDATE = "action.remote.click.update";

    public static final String ACTION_REMOTE_CLICK_HOUR = "action.remote.click.hour";

    public static final String DATE_AND_TIME_24HOUR_FORMAT = "yyyy-MM-dd HH:mm:ss";

    public static final String DATE_AND_TIME_12HOUR_FORMAT = "yyyy-MM-dd K:mm:ss a";

    public static final int RATE_UPDATE_TIME = 1000;

    private static Handler mHandler;

    private static WidgetUpdateTask mPendingUpdates;

    private static boolean mIs24Hour = true;

    private static int mProgress;

    @SuppressLint("NewApi")

    @Override

    public void onAppWidgetOptionsChanged(Context context, AppWidgetManager appWidgetManager, int appWidgetId,

            Bundle newOptions) {

        super.onAppWidgetOptionsChanged(context, appWidgetManager, appWidgetId, newOptions);

        d("[DateWidgetProvider]onAppWidgetOptionsChanged");

    }

    @Override

    public void onDeleted(Context context, int[] appWidgetIds) {

        super.onDeleted(context, appWidgetIds);

        d("[DateWidgetProvider]onDeleted");

        ComponentName provider = new ComponentName(context, this.getClass());

        int[] ids = AppWidgetManager.getInstance(context).getAppWidgetIds(provider);

        if (ids == null || ids.length == 0) {

            if (mPendingUpdates != null) {

                mPendingUpdates.stop();

                mPendingUpdates = null;

            }

        }

    }

    @Override

    public void onDisabled(Context context) {

        super.onDisabled(context);

        d("[DateWidgetProvider]onDisabled");

    }

    @Override

    public void onEnabled(Context context) {

        super.onEnabled(context);

        d("[DateWidgetProvider]onEnabled");

    }

    @Override

    public void onReceive(Context context, Intent intent) {

        super.onReceive(context, intent);

        d("[DateWidgetProvider]onReceive");

        d("intent=" + intent);

        final String action = intent.getAction();

        d("action=" + action);

        if (ACTION_REMOTE_CLICK_UPDATE.equals(action)) {

            if (mPendingUpdates != null) {

                mHandler.removeCallbacks(mPendingUpdates);

                mHandler.post(mPendingUpdates);

            }

        } else if (ACTION_REMOTE_CLICK_HOUR.equals(action)) {

            RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_main);

            mIs24Hour = !mIs24Hour;

            if (mIs24Hour) {

                views.setTextViewText(R.id.mBtnHour, context.getString(R.string.hour_24));

            } else {

                views.setTextViewText(R.id.mBtnHour, context.getString(R.string.hour_12));

            }

            ComponentName widgetComponent = new ComponentName(context, this.getClass());

            AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);

            appWidgetManager.updateAppWidget(widgetComponent, views);

            if (mPendingUpdates != null) {

                mHandler.removeCallbacks(mPendingUpdates);

                mHandler.post(mPendingUpdates);

            }

        }

    }

    @Override

    public void onRestored(Context context, int[] oldWidgetIds, int[] newWidgetIds) {

        super.onRestored(context, oldWidgetIds, newWidgetIds);

        d("[DateWidgetProvider]onRestored");

    }

    @Override

    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {

        super.onUpdate(context, appWidgetManager, appWidgetIds);

        d("[DateWidgetProvider]onUpdate");

        d("context:" + context);

        if (mHandler == null) {

            mHandler = new Handler(context.getMainLooper());

        }

        if (mPendingUpdates != null) {

            mHandler.removeCallbacks(mPendingUpdates);

        }

        mPendingUpdates = new WidgetUpdateTask(context, this, mHandler, RATE_UPDATE_TIME);

        mHandler.post(mPendingUpdates);

        RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_main);

        Intent intent = new Intent(ACTION_REMOTE_CLICK_UPDATE);

        PendingIntent pendingIntentUpdate = PendingIntent.getBroadcast(context, 0, intent,

                PendingIntent.FLAG_UPDATE_CURRENT);

        views.setOnClickPendingIntent(R.id.mTvDate, pendingIntentUpdate);

        intent = new Intent(ACTION_REMOTE_CLICK_HOUR);

        PendingIntent pendingIntent12Hour = PendingIntent.getBroadcast(context, 0, intent,

                PendingIntent.FLAG_UPDATE_CURRENT);

        views.setOnClickPendingIntent(R.id.mBtnHour, pendingIntent12Hour);

        appWidgetManager.updateAppWidget(appWidgetIds, views);

    }

    @SuppressLint("SimpleDateFormat")

    @Override

    public void onUpdateWidget(Context context) {

        ComponentName provider = new ComponentName(context, this.getClass());

        AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);

        int[] ids = appWidgetManager.getAppWidgetIds(provider);

        if (ids == null || ids.length == 0) {

            return;

        }

        Date date = new Date();

        SimpleDateFormat sdf;

        if (mIs24Hour) {

            sdf = new SimpleDateFormat(DATE_AND_TIME_24HOUR_FORMAT);

        } else {

            // DateFormatSymbols dfSymbols = new DateFormatSymbols();

            sdf = new SimpleDateFormat(DATE_AND_TIME_12HOUR_FORMAT);

        }

        String dateString = sdf.format(date);

        mProgress++;

        if (mProgress > 10)

            mProgress = 0;

        for (int appWidgetId : ids) {

            // d("update id:" + appWidgetId);

            RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_main);

            views.setTextViewText(R.id.mTvDate, dateString);

            views.setProgressBar(R.id.mProgressBar, 10, mProgress, false);

            appWidgetManager.updateAppWidget(appWidgetId, views);

        }

    }

}

AppWidgetProvider是BroadcastReciever的子类,因此实现的类也是一个reciver.
        (1)查看AppWidgetProvider的onReceiver方法源码,
            public void onReceive(Context context, Intent intent) {
                // Protect against rogue update broadcasts (not really a security issue,
                // just filter bad broacasts out so subclasses are less likely to crash).
                String action = intent.getAction();
                if (AppWidgetManager.ACTION_APPWIDGET_UPDATE.equals(action)) {
                    Bundle extras = intent.getExtras();
                    if (extras != null) {
                        int[] appWidgetIds = extras.getIntArray(AppWidgetManager.EXTRA_APPWIDGET_IDS);
                        if (appWidgetIds != null && appWidgetIds.length > 0) {
                            this.onUpdate(context, AppWidgetManager.getInstance(context), appWidgetIds);
                        }
                    }
                }
            }
        可以发现,当收到AppWidgetManager.ACTION_APPWIDGET_UPDATE消息时,将会自动调用onUpdate方法.因此在写onReceiver方法时,可以不处理此action.
        其它的action也会有相应的回调.
        AppWidgetManager.ACTION_APPWIDGET_DELETED -- onDeleted
        AppWidgetManager.ACTION_APPWIDGET_OPTIONS_CHANGED -- onAppWidgetOptionsChanged
        AppWidgetManager.ACTION_APPWIDGET_ENABLED -- onEnabled
        AppWidgetManager.ACTION_APPWIDGET_DISABLED -- onDisabled
       
        (2)public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds)
        当每创建一个widget时会调用一次onUpdate, appWidgetIds中会传入对应的id,注意,以前创建的widget的id不会传入.
       
        (3)onUpdate,onDeleted等方法传入时,this指针指向的是不同的对象,原因是BroadcastReciever在onReceive执行完毕之后被回收.

　　　　　　此后如需要更新时需要先调用接口getAppWidgetIds取得所有的id值.

　　　　　　ComponentName provider = new ComponentName(context, this.getClass());

　　　　　　AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
　　　　　　int[] ids = appWidgetManager.getAppWidgetIds(provider);
　　　　　　if (ids == null || ids.length == 0) {
　　　　　　　　return;
　　　　　　}

(4)实现类本身是一个BroadcastReceiver,因此可以在manifest.xml文件中注册其它的消息,以便更新界面信息.
        对按钮等控件的点击等消息,也通过消息发送.因此需要别的类处理的消息,需要使用BroadcastReceiver注册并响应.
        注意,如果在manifest.xml在本身的receiver中已经注册了某个消息,则别的BroadcastReceiver收不到该消息.

　　　(5)设置回调时,对不同的控件需要定义不同的action,不能在同一个action中定义不同的buddle等信息来区分响应消息,这样会导致收到的响应消息中,所有的buddle等信息都是最后设置的那个.　　　　
        
    4.修改manifest.xml中<application>节点下,注册实现的reciever类.其中android.appwidget.action.APPWIDGET_UPDATE是必须要添加的action,其它action如果设置了按钮响应等也可以在此添加,此后onReceiver中会收到对应的消息,但其它注册该action的receiver不能收到此消息.
        <receiver android:name="com.ahai.hellowidget.DateWidgetProvider" >
            <meta-data
                android:name="android.appwidget.provider"
                android:resource="@xml/widget_provider" />

<intent-filter>
                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
                <action android:name="action.remote.click.update" />
                <action android:name="action.remote.click.hour" />
            </intent-filter>
        </receiver>
       
二.相关的类说明
    1.RemoteViews, 一个可以在其他应用进程中运行的类, xml布局文件中定义了界面组件, 通过创建RemoteViews对象, 对widget的信息进行更新.
        (1) 创建RemoteViews对象
        RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_main);
       
        (2) 更新RemoteViews信息, 对界面信息的修改都需要调用RemoteViews类的方法updateAppWidget.
        注意,updateAppWidget有多个版本.通常用下面的两个方法:
            appWidgetManager.updateAppWidget(appWidgetIds, views);
           
            ComponentName widgetComponent = new ComponentName(context, this.getClass());
            appWidgetManager.updateAppWidget(widgetComponent, views);
        onUpdate中会传入对应的AppWidgetMannager对象.也可以自己取得此对象
            appWidgetManager = AppWidgetManager.getInstance(context).
       
        (3)定义回调
        Intent intent = new Intent(ACTION_REMOTE_CLICK_UPDATE);
  PendingIntent pendingIntentUpdate = PendingIntent.getBroadcast(context,
    0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
  views.setOnClickPendingIntent(R.id.mTvDate, pendingIntentUpdate);
       
        (4)更新Text和进度条
        views.setTextViewText(R.id.mTvDate, dateString);
        views.setProgressBar(R.id.mProgressBar, 10, mProgress, false);
       
    2.AppWidgetManger类, 负责管理 AppWidget, 向 AppwidgetProvider 发送通知
        bindAppWidgetId(int appWidgetId, ComponentName provider)
            通过给定的ComponentName 绑定appWidgetId
        getAppWidgetIds(ComponentName provider)
            通过给定的ComponentName 获取AppWidgetId
        getAppWidgetInfo(int appWidgetId)
            通过AppWidgetId 获取 AppWidget 信息
        getInstalledProviders()
            返回一个List<AppWidgetProviderInfo>的信息
        getInstance(Context context)
            获取 AppWidgetManger 实例使用的上下文对象
        updateAppWidget(int[] appWidgetIds, RemoteViews views)
            通过appWidgetId 对传进来的 RemoteView 进行修改，并重新刷新AppWidget 组件
        updateAppWidget(ComponentName provider, RemoteViews views)
            通过 ComponentName 对传进来的 RemoeteView 进行修改，并重新刷新AppWidget 组件
        updateAppWidget(int appWidgetId, RemoteViews views)
            通过appWidgetId 对传进来的 RemoteView 进行修改，并重新刷新AppWidget 组件

三.工具类代码

package com.ahai.hellowidget;

import java.util.Set;

import android.appwidget.AppWidgetManager;

import android.content.Context;

import android.os.Handler;

public class WidgetUpdateTask implements Runnable {

    public interface Callbacks {

        void onUpdateWidget(Context context, AppWidgetManager appWidgetManager,

                Set<Integer> ids);

    }

    private Context mContext;

    private AppWidgetManager mAppWidgetManager;

    private Set<Integer> mIDs;

    private boolean mIsStopped;

    private Callbacks mCallbacks;

    private Handler mHandler;

    private int mUpdateRate;

    public WidgetUpdateTask(Context context, AppWidgetManager appWidgetManager,

            Set<Integer> ids, Callbacks callbacks, Handler handler,

            int rateMills) {

        mContext = context;

        mAppWidgetManager = appWidgetManager;

        mIDs = ids;

        mCallbacks = callbacks;

        mHandler = handler;

        mUpdateRate = rateMills;

    }

    public void stop() {

        mIsStopped = true;

    }

    @Override

    public void run() {

        if (mIsStopped)

            return;

        mCallbacks.onUpdateWidget(mContext, mAppWidgetManager, mIDs);

        mHandler.postDelayed(this, mUpdateRate);

    }

}

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