Activity 报警后触发 (RTC_WAKEUP) 但屏幕仍然黑屏

Question

我正在设置一个关于如何对 Android 中的警报做出反应的骨架应用程序。当 phone 唤醒时一切正常，当 phone 睡眠时警报触发（我什至可以激活振动器）但屏幕保持关闭状态（完全黑）。我无法解释为什么。欢迎任何帮助！

这是 MainActivity 中设置 alarmManager 的代码片段（E1 是一个 EditText，要求用户选择秒数来触发警报）：

public void startAlarm(View view) {
    EditText E1 = (EditText) findViewById(R.id.et1);
    int i = Integer.parseInt(E1.getText().toString());
    Intent intent = new Intent(this, AlarmBroadcastReceiver.class);
    PendingIntent pending_intent = 
    PendingIntent.getBroadcast(this.getApplicationContext(),
        98989898, intent, 0); // 98989898 : some big number
    AlarmManager alarmManager = (AlarmManager) 
        getSystemService(ALARM_SERVICE);
    alarmManager.set(AlarmManager.RTC_WAKEUP, 
        System.currentTimeMillis() + i*1000, pending_intent);
    Toast.makeText(this, "Alarm set in: " + i + " seconds", 
    Toast.LENGTH_LONG).show();
}

警报由 alarmBroadcastReceiver 接收。它自己什么都不做，它立即转移到 UserResponseActivity:

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;

public class AlarmBroadcastReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        // We're creating a new intent that's going to start the UserResponseActivity
        Intent in = new Intent(context, UserResponseActivity.class);
        // This boolean just makes it easier to check if the Activity has been started from
        // this class
        in.putExtra("lock", true);
        // You need to add this to your intent if you want to start an Activity fromm a class
        // that is not an Activity itself
        in.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        // Now we just start the Activity
        context.startActivity(in);
    }
}

然后 UserResponseActivity 是一个普通的 activity，目前具有来自 Android Studio 的样板屏幕。稍后我计划添加一些代码来请求用户的响应。创建后，它显示祝酒词并在短时间内激活振动器：

import android.content.Context;
import android.os.Bundle;
import android.os.Vibrator;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.Toast;

public class UserResponseActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_user_response);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        /* Show a success toast*/
        Toast.makeText(this, "Alarm Started", Toast.LENGTH_LONG).show();
        /* Vibrate shortly */
        Vibrator vibrator = (Vibrator) this.getSystemService(Context.VIBRATOR_SERVICE);
        vibrator.vibrate(200);
    }

}

如果您需要，这里是我的清单中启用警报接收器和振动器服务的代码行：

<uses-permission android:name="android.permission.VIBRATE" />

<receiver android:name=".AlarmBroadcastReceiver" />

如前所述，如果在 phone 唤醒时触发警报，则一切正常：UserResponseActivity 显示在屏幕上并且振动器关闭。但是，如果在 phone 睡眠时触发警报，振动器将关闭（因此 phone 被唤醒并调用 UserResponseActivity）但屏幕保持黑色。当我随后打开 phone 时，UserResponseActivity 就在上面。

我需要做什么才能UserResponseActivity打开屏幕？

谢谢！

已添加（在 VicJordan 回复后）：

@VicJordan：我将你的代码粘贴到 UserResponseActivity.java 的 onCreate 中，如下所示，但是出现了两个错误，我无法找出我在这两行中做错了什么:

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
        activity.setTurnScreenOn(true);

a) Android Studio 无法解析符号 'O_MR1' b) 它可以在第二行解析 'activity' 。我认为将 activity 更改为 'this' 可以解决问题，但事实并非如此。我真的想不出另一种方式来引用 activity 我在

public class UserResponseActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_user_response);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        // Turn on the screen
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
            activity.setTurnScreenOn(true);
        } else {
            final Window window = getWindow();
            window.addFlags(WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
        }

        /* Show a success toast*/
        Toast.makeText(this, "Alarm Started", Toast.LENGTH_LONG).show();
        /* Vibrate shortly */
        Vibrator vibrator = (Vibrator) this.getSystemService(Context.VIBRATOR_SERVICE);
        vibrator.vibrate(200);
    }

您有什么建议吗？谢谢！

Answer 1

要在 Activity 中打开屏幕，您可以从 API 27 级开始使用 WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON but FLAG_TURN_SCREEN_ON flag has been deprecated in API level 27 so you can use Activity.setTurnScreenOn(true)。

代码如下：

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
        this.setTurnScreenOn(true);
    } else {
        final Window window = getWindow();
        window.addFlags(WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
    }

查看此官方信息以获取更多信息：https://developer.android.com/training/scheduling/wakelock

Activity 报警后触发 (RTC_WAKEUP) 但屏幕仍然黑屏

Activity triggers after alarm (RTC_WAKEUP) but screen remains black

android

alarmmanager