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处理程序在Android中的函数中工作不正常

android-handler android-studio android-layout android java

Aman Kimothi · 技术社区 · 8 年前

下面是我编写的代码,用于将某些视图的背景颜色亮度从128增加到255,反之亦然。不幸的是,应该让它等待的处理程序没有正常运行。请帮助我这个代码。

有一个3x3矩阵,其中有9个视图。我随机改变任何一个细胞的不透明度。

级别:我要逐个更改的单元格数。这里,级别:3

颜色[9]:包含9个视图的3x3矩阵。

public void pattern()  {

    for(int i=0;i<LEVEL;i++) {
        int rand= 0 + (int)(Math.random() * 8);
        computer+=rand;
        Log.d(" i :" , ""+i);
        Log.d(" random :" , ""+rand);
        Log.d("Pattern incoming " , ""+color[rand].getBackground().getAlpha());
        color[rand].getBackground().setAlpha(128);

        final int random=rand;
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                color[random].getBackground().setAlpha(128);
                Log.d("Inside handler " , ""+color[random].getBackground().getAlpha());
                color[random].getBackground().setAlpha(255);
            }
        },2000);

        color[rand].getBackground().setAlpha(128);

        Log.d("Outside handler " , ""+color[rand].getBackground().getAlpha());

    }
}

Android监视器Logcat

11-06 04:21:27.267 30640-30640/com.example.aman D/Â iÂ :: 0
11-06 04:21:27.267 30640-30640/com.example.aman D/Â randomÂ :: 1
11-06 04:21:27.267 30640-30640/com.example.aman D/PatternÂ incoming: 128
11-06 04:21:27.267 30640-30640/com.example.aman D/OutsideÂ handler: 128
11-06 04:21:27.267 30640-30640/com.example.aman D/Â iÂ :: 1
11-06 04:21:27.267 30640-30640/com.example.aman D/Â randomÂ :: 3
11-06 04:21:27.267 30640-30640/com.example.aman D/PatternÂ incoming: 128
11-06 04:21:27.267 30640-30640/com.example.aman D/OutsideÂ handler: 128
11-06 04:21:27.267 30640-30640/com.example.aman D/Â iÂ :: 2
11-06 04:21:27.267 30640-30640/com.example.aman D/Â randomÂ :: 7
11-06 04:21:27.267 30640-30640/com.example.aman D/PatternÂ incoming: 128
11-06 04:21:27.267 30640-30640/com.example.aman D/OutsideÂ handler: 128
11-06 04:21:27.267 30640-30640/com.example.aman D/Â randomÂ :: 7
11-06 04:21:27.267 30640-30640/com.example.aman D/PatternÂ incoming: 128
11-06 04:21:27.267 30640-30640/com.example.aman D/OutsideÂ handler: 128
$$ - 11-06 04:21:27.267 30640-30640/com.example.aman D/Inside handler: 128
$$ - 11-06 04:21:27.267 30640-30640/com.example.aman D/Inside handler: 128
$$ - 11-06 04:21:27.267 30640-30640/com.example.aman D/Inside handler: 128

如您所见,“内部处理程序”在循环结束时打印,循环运行了3次。我希望“内部处理程序”在“模式传入”之后和“外部处理程序”之前以以下方式执行:

11-06 04:21:27.267 30640-30640/com.example.aman D/Â iÂ :: 0
11-06 04:21:27.267 30640-30640/com.example.aman D/Â randomÂ :: 1
11-06 04:21:27.267 30640-30640/com.example.aman D/PatternÂ incoming: 128
$$ - 11-06 04:21:27.267 30640-30640/com.example.aman D/Inside handler: 128    
11-06 04:21:27.267 30640-30640/com.example.aman D/OutsideÂ handler: 128
11-06 04:21:27.267 30640-30640/com.example.aman D/Â iÂ :: 1
11-06 04:21:27.267 30640-30640/com.example.aman D/Â randomÂ :: 3
11-06 04:21:27.267 30640-30640/com.example.aman D/PatternÂ incoming: 128
$$ - 11-06 04:21:27.267 30640-30640/com.example.aman D/Inside handler: 128
11-06 04:21:27.267 30640-30640/com.example.aman D/OutsideÂ handler: 128
11-06 04:21:27.267 30640-30640/com.example.aman D/Â iÂ :: 2
11-06 04:21:27.267 30640-30640/com.example.aman D/Â randomÂ :: 7
11-06 04:21:27.267 30640-30640/com.example.aman D/PatternÂ incoming: 128
$$ - 11-06 04:21:27.267 30640-30640/com.example.aman D/Inside handler: 128
11-06 04:21:27.267 30640-30640/com.example.aman D/OutsideÂ handler: 128

1 回复 | 直到 8 年前

David Rawson B Aristide 8 年前

您在logcat中得到的结果与预期一样。让我们看看你写的:

1. first iteration of loop at time 1 ms
2. print "i :: 0"
3. print "random :: 1"
4. print "Pattern incoming :: 128"
5. post a task to the `Handler` to set the color 2 seconds from now (time 2005 ms)
6. print "Outside handler :: 128"
7. go on to next iteration of loop without waiting for the previous task to  complete 

8. second iteration of loop at time 8 ms:
9. print print "i :: 1"
10. print "random :: 3"
11. print "Pattern incoming :: 128"
12. post a task to the `Handler` to set the color 2 seconds from now (time 2012ms)
....
**loop terminates**
....
(finally a long time after the loop has completed the first scheduled task will be triggered)
....
2005. print "Inside handler: 128"

循环不会等待 Handler 在进入下一个迭代之前完成任务。

您现在的任务是重构代码,以便获得所需的效果。您可能需要使用 处理者 ,而不是将大量任务同步转储到。