Android-Widget桌面小组件
1,
掌握Widget的用:
Widget的用途,能够添加到手机桌面的程序
2,
Widget的特点和用法步骤:
特点:快捷,方便,个性化,可自定义功能,可及时控制更新Widget显示内容
3,
用法步骤流程图
- 绘制Widget布局
- 配置Widget的基本属性
- 定义AppWidgetProvider
- 提供Configuration Activity
4,
Android Widget实现一个基础的时钟功能
效果:
- 可以自动更新时间
- 可以添加和删除时钟Widget
5,
完整代码:
package com.example.widget; import android.appwidget.AppWidgetManager; import android.appwidget.AppWidgetProvider; import android.content.Context; import android.content.Intent; import android.widget.RemoteViews; /** * 类似广播,是桌面小组件Widget的Provider */ public class widget extends AppWidgetProvider { static void updateAppWidget(Context context, AppWidgetManager appWidgetManager, int appWidgetId) { CharSequence widgetText = context.getString(R.string.appwidget_text); // Construct the RemoteViews object RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget); views.setTextViewText(R.id.tv, widgetText); // Instruct the widget manager to update the widget appWidgetManager.updateAppWidget(appWidgetId, views); } //刷新widget的时候执行,remoteView和AppWidgetManager @Override public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) { // There may be multiple widgets active, so update all of them for (int appWidgetId : appWidgetIds) { updateAppWidget(context, appWidgetManager, appWidgetId); } } //第一个widget添加到屏幕上执行 @Override public void onEnabled(Context context) { // Enter relevant functionality for when the first widget is created super.onEnabled(context); //启动Service context.startService(new Intent(context, TimerService.class)); } //最后一个widget被从屏幕移除执行 @Override public void onDisabled(Context context) { // Enter relevant functionality for when the last widget is disabled super.onDisabled(context); context.stopService(new Intent(context, TimerService.class)); } //Widget被从屏幕移除 @Override public void onDeleted(Context context, int[] appWidgetIds) { super.onDeleted(context, appWidgetIds); } //这个方法一般不会重写,无论操作中间(上面)的哪些方法,都会执行onReceive @Override public void onReceive(Context context, Intent intent) { super.onReceive(context, intent); } }
service:
package com.example.widget; import android.app.Service; import android.appwidget.AppWidgetManager; import android.content.ComponentName; import android.content.Intent; import android.os.IBinder; import android.widget.RemoteViews; import androidx.annotation.Nullable; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Timer; import java.util.TimerTask; public class TimerService extends Service { //java.util.Timer下的定时器 private Timer timer; private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); @Nullable @Override public IBinder onBind(Intent intent) { return null; } @Override public void onCreate() { super.onCreate(); timer = new Timer(); timer.schedule(new TimerTask() { @Override public void run() { updateViews(); } }, 0, 1000); } private void updateViews() { String time = sdf.format(new Date()); RemoteViews rv = new RemoteViews(getPackageName(), R.layout.widget); rv.setTextViewText(R.id.tv, "黄朝阳666 : " + time); AppWidgetManager manager = AppWidgetManager.getInstance(getApplicationContext()); ComponentName cn = new ComponentName(getApplicationContext(), widget.class); manager.updateAppWidget(cn, rv); } @Override public void onDestroy() { super.onDestroy(); timer = null; } }
6,
添加和删除天气Widget:
7,
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