Question

我有Qt应用程序，需要在应用程序运行时防止屏幕变暗。我将以下代码放在main.cpp中main（）的开头：

#ifdef ANDROID
    // disable screen lock on android devices
    QAndroidJniObject activity = QtAndroid::androidActivity();
    if (activity.isValid()) {
        QAndroidJniObject window = activity.callObjectMethod("getWindow", "()Landroid/view/Window;");

        if (window.isValid()) {
            const int FLAG_KEEP_SCREEN_ON = 128;
            window.callMethod<void>("addFlags", "(I)V", FLAG_KEEP_SCREEN_ON);
        }
    }
#endif

其中几乎来自：How to keep the screen on in Qt for android?，但我使用的是callMethod<void>而不是callObjectMethod。

问题是，当应用程序启动时，它会与巨大的Java日志崩溃，我怀疑这是它的相关部分：

F/art     (26455): art/runtime/runtime.cc:289] Pending exception android.view.ViewRootImpl$CalledFromWrongThreadException thrown by 'unknown throw location'
F/art     (26455): art/runtime/runtime.cc:289] android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
F/art     (26455): art/runtime/runtime.cc:289]   at void android.view.ViewRootImpl.checkThread() (ViewRootImpl.java:6357)
F/art     (26455): art/runtime/runtime.cc:289]   at void android.view.ViewRootImpl.requestLayout() (ViewRootImpl.java:874)
F/art     (26455): art/runtime/runtime.cc:289]   at void android.view.View.requestLayout() (View.java:17476)
F/art     (26455): art/runtime/runtime.cc:289]   at void android.view.View.setLayoutParams(android.view.ViewGroup$LayoutParams) (View.java:11477)
F/art     (26455): art/runtime/runtime.cc:289]   at void android.view.WindowManagerGlobal.updateViewLayout(android.view.View, android.view.ViewGroup$LayoutParams) (WindowManagerGlobal.java:305)
F/art     (26455): art/runtime/runtime.cc:289]   at void android.view.WindowManagerImpl.updateViewLayout(android.view.View, android.view.ViewGroup$LayoutParams) (WindowManagerImpl.java:91)
F/art     (26455): art/runtime/runtime.cc:289]   at void android.app.Activity.onWindowAttributesChanged(android.view.WindowManager$LayoutParams) (Activity.java:2596)
F/art     (26455): art/runtime/runtime.cc:289]   at void org.qtproject.qt5.android.bindings.QtActivity.onWindowAttributesChanged(android.view.WindowManager$LayoutParams) (QtActivity.java:1385)
F/art     (26455): art/runtime/runtime.cc:289]   at void android.view.Window.dispatchWindowAttributesChanged(android.view.WindowManager$LayoutParams) (Window.java:836)
F/art     (26455): art/runtime/runtime.cc:289]   at void com.android.internal.policy.impl.PhoneWindow.dispatchWindowAttributesChanged(android.view.WindowManager$LayoutParams) (PhoneWindow.java:3993)
F/art     (26455): art/runtime/runtime.cc:289]   at void android.view.Window.setFlags(int, int) (Window.java:813)
F/art     (26455): art/runtime/runtime.cc:289]   at void android.view.Window.addFlags(int) (Window.java:771)

我在AndroidManifest.xml中添加了适当的权限（android.permission.WAKE_LOCK）。问题似乎是由于在主视图之外运行addFlags（）引起的？我用Google搜索了一下，找不到其他人有同样的问题。

谢谢，伊万

Answer 1

#!/bin/bash
cd ~/deploy
rm -R $( ls -td */ | tail -n 1 )

从here得到它，适用于我的5.1 android井

Answer 2

在Android上部署时，Qt实际上并不在主应用程序（Java）线程中运行。由于必须从Java主线程调用android.view.Window.addFlags，因此您很难回到此线程以使此代码有效。

最好是使用WakeLock来阻止系统进入睡眠模式。 here is a post explaining how to do it

这可以防止屏幕在应用程序运行时变暗。

Answer 3

我最终用Java做了这个。

这是java代码：

package org.qtproject.visualization;

import org.qtproject.qt5.android.bindings.*;
import android.os.Bundle;
import android.view.WindowManager;

public class ScreenOnActivity extends QtActivity
{
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        getWindow().addFlags( WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON );
        super.onCreate(savedInstanceState);
    }
}

然后将其集成到应用程序的其余部分。

Qt android屏幕锁定java问题

3 个答案: