背景

项目中有时需要在安卓桌面添加widget,方便用户查看或做一些操作.

Demo实现效果图

用于实现一个显示日期的widget

实现步骤

1. 新建widget

2. 选择占用屏幕空间的大小

3. 自动生成的代码文件

4. 主要代码如下:

class TimerService : Service() {

    private lateinit var rv: RemoteViews

    private lateinit var manager: AppWidgetManager

    // 定义定时器
    private lateinit var timer: Timer

    // 定义格式化日期时间
    @SuppressLint("SimpleDateFormat")
    private val sdf = SimpleDateFormat("HH : mm-MM / dd   E")

    override fun onCreate() {
        super.onCreate()

        timer = Timer()
        timer.schedule(object : TimerTask() {
            override fun run() {
                updateViews()
            }
        }, 0, 1000)
    }

    private fun updateViews() {

        rv = RemoteViews(packageName, R.layout.time_widget)
        val cn = ComponentName(applicationContext, WidgetProvider::class.java)
        manager = AppWidgetManager.getInstance(applicationContext)

        val str = sdf.format(Date())
        val timeStr = str.substring(0, 7)
        rv.setTextViewText(R.id.timeTv, timeStr)
        manager.updateAppWidget(cn, rv)
    }

    override fun onDestroy() {
        super.onDestroy()
        timer.cancel()
    }

    override fun onBind(arg0: Intent): IBinder? {
        return null
    }
}

class WidgetProvider : AppWidgetProvider() {

    override fun onReceive(context: Context, intent: Intent) {
        // 接收开机和启动程序时候的广播时执行
        super.onReceive(context, intent)
        context.startService(Intent(context, TimerService::class.java))
    }

    override fun onEnabled(context: Context) {
        // Widget添加到屏幕时执行
        super.onEnabled(context)
        context.startService(Intent(context, TimerService::class.java))
    }

    override fun onDisabled(context: Context) {
        // 最后一次Widget从屏幕移除时执行
        super.onDisabled(context)
        context.stopService(Intent(context, TimerService::class.java))
    }
}

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.cxyzy.desktopwidgetdemo">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        tools:ignore="GoogleAppIndexingWarning">
        <receiver android:name=".WidgetProvider">
            <intent-filter>
                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
            </intent-filter>

            <meta-data
                android:name="android.appwidget.provider"
                android:resource="@xml/time_widget_info" />
        </receiver>

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service android:name=".TimerService" />
    </application>

</manifest>

5. 运行安装app后,在手机上添加桌面控件

6. FAQ

一定要保持app是运行的,否则widget就不会更新了.

完整代码

https://gitee.com/cxyzy1/desktopWidgetDemo