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

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，

8，

秒客网

Android-Widget桌面小组件

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