将 Textview 发送到小部件

Question

我将为倒计时创建一个小部件。布局已完成，但我无法将 Mainactivity 的 Textview 发送到小部件。我尝试了很多人在这里发布的不同的东西，但它不起作用。我是应用程序编程的初学者，我希望有人可以很容易地描述这一点。 我试过这个（How to share data between activity and widget?），但也许我忘记了一些不起作用的东西。

这是我的 MainActivity 代码：

public class MainActivity extends AppCompatActivity {

    private TextView txtTimerDay, txtTimerHour, txtTimerMinute, txtTimerSecond;
    private TextView tvEvent;
    private Handler handler;
    private Runnable runnable;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        txtTimerDay = (TextView) findViewById(R.id.txtTimerDay);
        txtTimerHour = (TextView) findViewById(R.id.txtTimerHour);
        txtTimerMinute = (TextView) findViewById(R.id.txtTimerMinute);
        txtTimerSecond = (TextView) findViewById(R.id.txtTimerSecond);
        tvEvent = (TextView) findViewById(R.id.tvhappyevent);
        setContentView(R.layout.widget);
        txtTimerDay = (TextView) findViewById(R.id.txtTimerDay);
        txtTimerHour = (TextView) findViewById(R.id.txtTimerHour);
        txtTimerMinute = (TextView) findViewById(R.id.txtTimerMinute);
        txtTimerSecond = (TextView) findViewById(R.id.txtTimerSecond);
        countDownStart();
    }
    public void countDownStart() {
        handler = new Handler();
        runnable = new Runnable() {
            @Override
            public void run() {
                handler.postDelayed(this, 1000);
                try {
                    SimpleDateFormat dateFormat = new SimpleDateFormat(
                        "yyyy-MM-dd");
                    // Please here set your event date//YYYY-MM-DD
                    Date futureDate = dateFormat.parse("2021-12-24");
                    Date currentDate = new Date();
                    if (!currentDate.after(futureDate)) {
                        long diff = futureDate.getTime()
                                - currentDate.getTime();
                        long days = diff / (24 * 60 * 60 * 1000);
                        diff -= days * (24 * 60 * 60 * 1000);
                        long hours = diff / (60 * 60 * 1000);
                        diff -= hours * (60 * 60 * 1000);
                        long minutes = diff / (60 * 1000);
                        diff -= minutes * (60 * 1000);
                        long seconds = diff / 1000;
                        txtTimerDay.setText("" + String.format("%02d", days));
                        txtTimerHour.setText("" + String.format("%02d", hours));
                        txtTimerMinute.setText(""
                                + String.format("%02d", minutes));
                        txtTimerSecond.setText(""
                                + String.format("%02d", seconds));
                    } else {
                        tvEvent.setVisibility(View.VISIBLE);
                        tvEvent.setText("The event started!");
                        textViewGone();
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        };
        handler.postDelayed(runnable, 1 * 1000);
    }
    public void textViewGone() {
        findViewById(R.id.LinearLayout10).setVisibility(View.GONE);
        findViewById(R.id.LinearLayout11).setVisibility(View.GONE);
        findViewById(R.id.LinearLayout12).setVisibility(View.GONE);
        findViewById(R.id.LinearLayout13).setVisibility(View.GONE);
    }
}

这里是清单：

<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/Theme.App">
    <receiver android:name=".Widget">
        <intent-filter>
            <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
        </intent-filter>
        <meta-data
            android:name="android.appwidget.provider"
            android:resource="@xml/widget_info" />
    </receiver>
    <activity
        android:name=".MainActivity"
        android:screenOrientation="landscape">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

Answer 1

很遗憾，您不能像这样直接从您的活动中设置小部件的内容。相反，您需要定义自己的 AppWidgetProvider，检索它的一个实例并调用它的 onUpdate 函数并使用 RemoteViews 重新创建 UI。

您可以找到有关此主题的指南here。话虽如此，在 Android 上使用小部件可能有点复杂，这可能不适合初学者。