android widget

 

widget的生命周期非常特别。创建方式如下：

（1）创建AndroidManifest.xml，注销主activity 的申明部分代码：

<!--
   <activity android:name=".widgetProvider"
   android:label="@string/app_name"> <intent-filter> <action
   android:name="android.intent.action.MAIN" /> <category
   android:name="android.intent.category.LAUNCHER" /> </intent-filter>
   </activity>
  -->

（2）增加在res/xml/下增加appwidget_provider.xml的申明

<?xml version="1.0" encoding="UTF-8"?>
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
    android:minWidth="294dp"    --这个代表占用四个格子宽度，(number of cells * 74) - 2
    android:minHeight="72dp"  --这个
    android:updatePeriodMillis="86400000"
    android:initialLayout="@layout/main">
</appwidget-provider>

（3）派生类AppWidgetProvider，写自己的onUpdate和onReceive：

package com.terry;

import java.util.Timer;

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.net.Uri;
import android.widget.RemoteViews;
import android.widget.Toast;

public class widgetProvider extends AppWidgetProvider {
 public static final String CLICK_NAME_ACTION = "com.terry.action.widget.click";

 private static RemoteViews rv;

 @Override
 public void onUpdate(Context context, AppWidgetManager appWidgetManager,
   int[] appWidgetIds) {
  // TODO Auto-generated method stub
  Timer timer = new Timer();

  timer.scheduleAtFixedRate(new MyTime(context,appWidgetManager), 1, 300000);
     
 }

 @Override
 public void onReceive(Context context, Intent intent) {
  // TODO Auto-generated method stub
  super.onReceive(context, intent);

  if (rv == null) {
   rv = new RemoteViews(context.getPackageName(), R.layout.main);
  }
  if (intent.getAction().equals(CLICK_NAME_ACTION)) {
        Uri uri = Uri.parse("geo:38.899533,-77.036476");
    Intent it = new Intent(Intent.ACTION_VIEW,uri);
    context.startActivity(it);
  }
  
  AppWidgetManager appWidgetManger = AppWidgetManager
    .getInstance(context);
  int[] appIds = appWidgetManger.getAppWidgetIds(new ComponentName(
    context, widgetProvider.class));
  appWidgetManger.updateAppWidget(appIds, rv);
 }

  }

（4）如何动态界面元素。

widget设计和app类似，但控制动态元素则区别较大。

增加事件的方法，控件ID传入appWidgetId即可：

 public static void updateAppWidget(Context context,
   AppWidgetManager appWidgeManger, int controlID,String command) {
  rv = new RemoteViews(context.getPackageName(), R.layout.main);
  Intent intentClick = new Intent(command);
  PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0,
    intentClick, 0);
  rv.setOnClickPendingIntent(controlID, pendingIntent);
  ComponentName appWidgetId = new ComponentName(context,
    widgetProvider.class);
  appWidgeManger.updateAppWidget(appWidgetId, rv);
 }

增加事件消息：

public static final String CLICK_NAME_ACTION = "com.terry.action.widget.click";
 public static final String CLICK_FRESH_ACTION = "com.terry.action.widget.fresh";

在XML中需要增加响应：

<receiver android:name=".widgetProvider">
   <meta-data android:name="android.appwidget.provider"
    android:resource="@xml/appwidget_provider"></meta-data>
   <intent-filter>
    <action android:name="com.terry.action.widget.click"></action>
    <action android:name="com.terry.action.widget.fresh"></action> 
     <action android:name="android.appwidget.action.APPWIDGET_UPDATE" /> 
     <category android:name="android.intent.category.LAUNCHER" />
   </intent-filter>
  </receiver>

最后在Onreciver中处理事件消息：

public void onReceive(Context context, Intent intent) {
  // TODO Auto-generated method stub
  super.onReceive(context, intent);

  try {
   if (rv == null) {
    rv = new RemoteViews(context.getPackageName(), R.layout.main);
   }
   if (intent.getAction().equals( CLICK_NAME_ACTION)) { //to do

}}}

修改控件属性的方法择非常多，类似如下

rv.setTextViewText(R.id.TextView01,"hello");//rv.setImageViewResource(R.id.imageView2,R.drawable.zh3)
appWidgetManger.updateAppWidget(appIds, rv);