我的程序在后台线程中执行一些网络活动。在开始之前,它会弹出一个进度对话框。该对话框在处理程序上被解除。这一切都很好,除了当对话框打开时屏幕方向发生变化(背景线程正在运行)。此时,应用程序要么崩溃,要么死锁,要么进入一个奇怪的阶段,在所有线程被杀死之前,应用程序根本无法工作。

我如何处理屏幕方向的变化优雅?

下面的示例代码大致匹配我的实际程序:

public class MyAct extends Activity implements Runnable {
    public ProgressDialog mProgress;

    // UI has a button that when pressed calls send

    public void send() {
         mProgress = ProgressDialog.show(this, "Please wait", 
                      "Please wait", 
                      true, true);
        Thread thread = new Thread(this);
        thread.start();
    }

    public void run() {
        Thread.sleep(10000);
        Message msg = new Message();
        mHandler.sendMessage(msg);
    }

    private final Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            mProgress.dismiss();
        }
    };
}

栈:

E/WindowManager(  244): Activity MyAct has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@433b7150 that was originally added here
E/WindowManager(  244): android.view.WindowLeaked: Activity MyAct has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@433b7150 that was originally added here
E/WindowManager(  244):     at android.view.ViewRoot.<init>(ViewRoot.java:178)
E/WindowManager(  244):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:147)
E/WindowManager(  244):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:90)
E/WindowManager(  244):     at android.view.Window$LocalWindowManager.addView(Window.java:393)
E/WindowManager(  244):     at android.app.Dialog.show(Dialog.java:212)
E/WindowManager(  244):     at android.app.ProgressDialog.show(ProgressDialog.java:103)
E/WindowManager(  244):     at android.app.ProgressDialog.show(ProgressDialog.java:91)
E/WindowManager(  244):     at MyAct.send(MyAct.java:294)
E/WindowManager(  244):     at MyAct$4.onClick(MyAct.java:174)
E/WindowManager(  244):     at android.view.View.performClick(View.java:2129)
E/WindowManager(  244):     at android.view.View.onTouchEvent(View.java:3543)
E/WindowManager(  244):     at android.widget.TextView.onTouchEvent(TextView.java:4664)
E/WindowManager(  244):     at android.view.View.dispatchTouchEvent(View.java:3198)

我已经尝试在onSaveInstanceState中取消进度对话框,但这只是防止了立即崩溃。背景线程仍在运行,UI处于部分绘制状态。需要在它重新开始工作之前杀死整个应用程序。


当前回答

当你改变方向时,Android会终止那个活动并创建新的活动。 我建议使用Rx java的retrofit。自动处理崩溃。

在改造调用时使用这些方法。

.subscribeOn (Schedulers.io ()) .observeOn (AndroidSchedulers.mainThread ())

其他回答

将长任务移动到单独的类中。将其实现为主题-观察者模式。每当创建活动时,注册并在关闭时注销任务类。任务类可以使用AsyncTask。

这是一个非常古老的问题,出于某种原因出现在侧栏上。

如果后台任务只需要在活动处于前台时存活,“新的”解决方案是在保留的片段中托管后台线程(或者,最好是AsyncTask),如本开发指南和大量q&a中所述。

如果活动因配置更改而被销毁,则保留的片段将继续存在,但当活动在后台或后台堆栈中被销毁时则不存在。因此,如果onPause()中的isChangingConfigurations()为false,后台任务仍然应该被中断。

If you're struggling with detecting orientation change events of a dialog INDEPENDENT OF AN ACTIVITY REFERENCE, this method works excitingly well. I use this because I have my own dialog class that can be shown in multiple different Activities so I don't always know which Activity it's being shown in. With this method you don't need to change the AndroidManifest, worry about Activity references, and you don't need a custom dialog (as I have). You do need, however, a custom content view so you can detect the orientation changes using that particular view. Here's my example:

设置

public class MyContentView extends View{
    public MyContentView(Context context){
        super(context);
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig){
        super.onConfigurationChanged(newConfig);

        //DO SOMETHING HERE!! :D
    }
}

实现1 -对话

Dialog dialog = new Dialog(context);
//set up dialog
dialog.setContentView(new MyContentView(context));
dialog.show();

实现2 - AlertDialog。构建器

AlertDialog.Builder builder = new AlertDialog.Builder(context);
//set up dialog builder
builder.setView(new MyContentView(context));        //Can use this method
builder.setCustomTitle(new MycontentView(context)); // or this method
builder.build().show();

实现3 - ProgressDialog / AlertDialog

ProgressDialog progress = new ProgressDialog(context);
//set up progress dialog
progress.setView(new MyContentView(context));        //Can use this method
progress.setCustomTitle(new MyContentView(context)); // or this method
progress.show();

我发现了一个我还没有在其他地方见过的解决方案。你可以使用一个自定义应用程序对象,它知道你是否有后台任务在进行,而不是试图在活动中做这件事,在方向改变时被销毁和重新创建。我在这里写过博客。

我的解决方案是扩展ProgressDialog类来获得我自己的MyProgressDialog。

我重新定义了show()和dismiss()方法来在显示对话框之前锁定方向,并在对话框被解散时将其解锁。

因此,当显示对话框并且设备的方向发生变化时,屏幕的方向保持不变,直到调用dismiss(),然后屏幕方向根据传感器值/设备方向发生变化。

这是我的代码:

public class MyProgressDialog extends ProgressDialog {
    private Context mContext;

    public MyProgressDialog(Context context) {
        super(context);
        mContext = context;
    }

    public MyProgressDialog(Context context, int theme) {
        super(context, theme);
        mContext = context;
    }
    
    public void show() {
        if (mContext.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT)
            ((Activity) mContext).setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        else
            ((Activity) mContext).setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
        super.show();
    }
    
    public void dismiss() {
        super.dismiss();
        ((Activity) mContext).setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR);
    }
}