Android 如何使通知意图恢复而不是制作新意图？

How to make notification intent resume rather than making a new intent?

提问by brybam

What i have here is a simple webview activity that when loaded it auto displays an ongoing notification. The idea is that people can navigate away from this activity and quickly access it again from any screen they want by pulling down the drop down menu and selecting it. Then when they want they can just close the notification by hitting the menu button and hitting exit and then the notification clears. This all works fine. However, when the notification is pressed it starts a new instance of the activity. What would i have to change to make it see if the activity has not already been destroyed and i can just call that instance back(resume it) and therefore not needing to load it again and won't need to add another activity to my stack. Any ideas? Any help would be greatly appreciated.

我这里有一个简单的 webview 活动，加载时它会自动显示正在进行的通知。这个想法是人们可以离开这个活动并通过下拉下拉菜单并选择它从他们想要的任何屏幕快速再次访问它。然后，当他们想要时，他们可以通过点击菜单按钮并点击退出来关闭通知，然后通知就会清除。这一切正常。但是，当按下通知时，它会启动一个新的 Activity 实例。我需要更改什么才能查看活动是否尚未被销毁，我可以只调用该实例（恢复它），因此不需要再次加载它，也不需要将另一个活动添加到我的堆栈中. 有任何想法吗？任何帮助将不胜感激。

package com.my.app;

import com.flurry.android.FlurryAgent;

import android.app.Activity;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent; 
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.webkit.CookieSyncManager;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;

public class Chat extends Activity { 
    private ProgressDialog progressBar;
    public WebView webview;
    private static final String TAG = "Main";

    private NotificationManager mNotificationManager;
    private int SIMPLE_NOTFICATION_ID;

    @Override
    public void onStart() {
       super.onStart();
       CookieSyncManager.getInstance().sync();
       FlurryAgent.onStartSession(this, "H9QGMRC46IPXB43GYWU1");
    }

    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.chat);

        mNotificationManager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);

        final Notification notifyDetails = new Notification(R.drawable.chat_notification,"Chat Started",System.currentTimeMillis());

        notifyDetails.flags |= Notification.FLAG_ONGOING_EVENT;

        Context context = getApplicationContext();

        CharSequence contentTitle = "Chat";
        CharSequence contentText = "Press to return to chat";

        Intent notifyIntent = new Intent(context, Chat.class);

        PendingIntent intent =
        PendingIntent.getActivity(Chat.this, 0,
        notifyIntent, android.content.Intent.FLAG_ACTIVITY_NEW_TASK);
        notifyDetails.setLatestEventInfo(context, contentTitle, contentText, intent);

        mNotificationManager.notify(SIMPLE_NOTFICATION_ID, notifyDetails);

        CookieSyncManager.createInstance(this);
        CookieSyncManager.getInstance().startSync();
        webview = (WebView) findViewById(R.id.webviewchat);
        webview.setWebViewClient(new chatClient());
        webview.getSettings().setJavaScriptEnabled(true);
        webview.getSettings().setPluginsEnabled(true);
        webview.loadUrl("http://google.com");

        progressBar = ProgressDialog.show(Chat.this, "", "Loading Chat...");  
    }

    private class chatClient extends WebViewClient { 
        @Override 
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            Log.i(TAG, "Processing webview url click...");
            view.loadUrl(url);
            return true;
        }

        public void onPageFinished(WebView view, String url) {
            Log.i(TAG, "Finished loading URL: " +url);
            if (progressBar.isShowing()) {
                progressBar.dismiss();
            }
        }
    }

    public boolean onKeyDown(int keyCode, KeyEvent event) { 
        if ((keyCode == KeyEvent.KEYCODE_BACK) && webview.canGoBack()) { 
            webview.goBack(); 
            return true; 
        }
        return super.onKeyDown(keyCode, event); 
    }

    @Override
    public boolean onCreateOptionsMenu (Menu menu) {
        super.onCreateOptionsMenu(menu);
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.chatmenu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected (MenuItem item) {
        switch (item.getItemId()) {
            case R.id.home:
                Intent a = new Intent(this, Home.class);
                startActivity(a);
                return true;
            case R.id.closechat:
                mNotificationManager.cancel(SIMPLE_NOTFICATION_ID);
                Intent v = new Intent(this, Home.class);
                startActivity(v);
                return true;
        }
        return false;
    }

    public void onStop() {
       super.onStop();
       CookieSyncManager.getInstance().sync();
       FlurryAgent.onEndSession(this);
    }
}

@Commonsware

@Commonsware

Just to be sure i have it correct, is this what you were suggesting?

只是为了确保我说的是正确的，这就是你的建议吗？

I was a little worried about this line,

我有点担心这条线，

PendingIntent.getActivity(Chat.this, 0, notifyIntent, SIMPLE_NOTFICATION_ID);

public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState);
    setContentView(R.layout.chat);

    mNotificationManager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);

    final Notification notifyDetails = new Notification(R.drawable.chat_notification,"Chat Started",System.currentTimeMillis());

    notifyDetails.flags |= Notification.FLAG_ONGOING_EVENT;


    Context context = getApplicationContext();

    CharSequence contentTitle = "Chat";
    CharSequence contentText = "Press to return to chat";

    Intent notifyIntent = new Intent(context, Chat.class);

    PendingIntent intent =
    PendingIntent.getActivity(Chat.this, 0, notifyIntent, SIMPLE_NOTFICATION_ID);
    notifyDetails.setLatestEventInfo(context, contentTitle, contentText, intent);
    notifyIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);

    mNotificationManager.notify(SIMPLE_NOTFICATION_ID, notifyDetails);


    CookieSyncManager.createInstance(this);
    CookieSyncManager.getInstance().startSync();
    webview = (WebView) findViewById(R.id.webviewchat);
    webview.setWebViewClient(new chatClient());
    webview.getSettings().setJavaScriptEnabled(true);
    webview.getSettings().setPluginsEnabled(true);
    webview.loadUrl("http://google.com");

    progressBar = ProgressDialog.show(Chat.this, "", "Loading Chat...");        
}

回答by CommonsWare

The idea is that people can navigate away from this activity and quickly access it again from any screen they want by pulling down the drop down menu and selecting it.

这个想法是人们可以离开这个活动并通过下拉下拉菜单并选择它从他们想要的任何屏幕快速再次访问它。

Please make this optional.

请将此选项设为可选。

However, when the notification is pressed it starts a new instance of the activity.

但是，当按下通知时，它会启动一个新的 Activity 实例。

That will happen by default.

默认情况下会发生这种情况。

What would i have to change to make it see if the activity has not already been destroyed and i can just call that instance back(resume it) and therefore not needing to load it again and won't need to add another activity to my stack.

我需要更改什么才能查看活动是否尚未被销毁，我可以只调用该实例（恢复它），因此不需要再次加载它，也不需要将另一个活动添加到我的堆栈中.

Get rid of FLAG_ACTIVITY_NEW_TASK. Add notifyIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);-- see this sample project.

摆脱FLAG_ACTIVITY_NEW_TASK. 添加notifyIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);- 请参阅此示例项目。

Context context = getApplicationContext();

Please don't do this. Just use your Activityas a Context.

请不要这样做。只需将您的Activity用作Context.

回答by Pedro Rom?o

This is my method to show notifications. I hope it helps you.

这是我显示通知的方法。我希望它能帮助你。

private static void generateNotification(Context context, String message){
    Intent notificationIntent = new Intent(context, YOUR_ACTIVITY.class);
    notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
    PendingIntent intent = PendingIntent.getActivity(context, 0, notificationIntent, 0);

    NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context)
        .setSmallIcon(R.drawable.ic_launcher)
        .setContentTitle(context.getString(R.string.app_name))
        .setContentIntent(intent)
        .setPriority(PRIORITY_HIGH) //private static final PRIORITY_HIGH = 5;
        .setContentText(message)
        .setAutoCancel(true)
        .setDefaults(Notification.DEFAULT_SOUND | Notification.DEFAULT_VIBRATE | Notification.DEFAULT_LIGHTS);
    NotificationManager mNotificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
    mNotificationManager.notify(0, mBuilder.build());
}

回答by jkincali

Just in case someone else has the same difficulty I had....

以防万一其他人遇到和我一样的困难......

I tried all the code above without success - the notification item kept launching a completely new instance of my app even though one was already running. (I only want one instance to be available at any one time.) Finally noticed this other thread (https://stackoverflow.com/a/20724199/4307281), which had one simple additional entry needed in the manifest:

我尝试了上面的所有代码都没有成功 - 即使一个应用程序已经在运行，通知项也会继续启动我的应用程序的一个全新实例。（我只希望在任何时候都有一个实例可用。）最后注意到另一个线程（https://stackoverflow.com/a/20724199/4307281），它在清单中需要一个简单的附加条目：

android:launchMode="singleInstance"

android:launchMode="singleInstance"

I placed that in the manifest under the main activity section of my application and then the notification item reused the already-in-progress instance.

我将它放在我的应用程序的主要活动部分下的清单中，然后通知项重用了已经在进行中的实例。

回答by TharakaNirmana

Non of the solutions worked for me so I found my own way. All my activities are extended from a BaseActivity. I followed a simple series of steps to make my push notification click resume the application:

没有一个解决方案对我有用，所以我找到了自己的方式。我所有的活动都是从一个BaseActivity. 我按照一系列简单的步骤让我的推送通知点击恢复应用程序：

Step 1 : Constant to record the Current Activity:

第 1 步：记录当前活动的常量：

public static Context currentContext;

Step 2 : in onCreate()or onResume()of activities extended by BaseActivity

第 2 步：在onCreate()或onResume()延长的活动中BaseActivity

currentContext = this;

Step 3 : Intentwhen creating the notification:

第 3 步：Intent创建通知时：

Class activity = BaseActivity.commonContext.getClass();
Intent intent = new Intent(this, activity);
intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

//FLAG_UPDATE_CURRENT is important
PendingIntent pendingIntent = PendingIntent.getActivity(this, (int)System.currentTimeMillis(), intent, PendingIntent.FLAG_UPDATE_CURRENT);

回答by dhakim

I found that none of the answers worked for a multi task application. It seems that, understandably, Intent.FLAG_ACTIVITY_CLEAR_TOP and Intent.FLAG_ACTIVITY_SINGLE_TOP do not behave exactly the same in the case of multiple tasks. In my application, there are multiple task root activities. At some point, the user will be shown a notification that there is work to be done in one of these tasks. Unlike the OP, I only need to return to the top of one of these tasks, not to a specific activity, which may be buried in one of these tasks. I think that this is similar enough to the asked question that it may be of use to someone else.

我发现没有一个答案适用于多任务应用程序。似乎可以理解的是， Intent.FLAG_ACTIVITY_CLEAR_TOP 和 Intent.FLAG_ACTIVITY_SINGLE_TOP 在多个任务的情况下表现并不完全相同。在我的应用程序中，有多个任务根活动。在某些时候，用户将收到一条通知，告知其中一项任务需要完成。与 OP 不同的是，我只需要返回其中一个任务的顶部，而不是返回到某个特定的 Activity，它可能会被埋在其中一个任务中。我认为这与提出的问题足够相似，它可能对其他人有用。

My solution consists of a static task id to keep track of the current task, a broadcast receiver to handle pending intents, a new uses-permission tag, and some simple use of the ActivityManager.

我的解决方案包括一个静态任务 id 来跟踪当前任务，一个广播接收器来处理挂起的意图，一个新的使用权限标签，以及 ActivityManager 的一些简单使用。

private static int taskID;

public static void setResumeTask(int tID)
{
    Log.e("TaskReturn", "Setting Task ID: " + tID);
    taskID = tID;
}

public static PendingIntent getResumeTask(Context appContext)
{
    return PendingIntent.getBroadcast(appContext, 0, new Intent(appContext, TaskReturn.class).putExtra(TaskReturn.EXTRA_TASK_ID, taskID), PendingIntent.FLAG_UPDATE_CURRENT);
}

---

---

public void onReceive(Context context, Intent intent)
{
    Log.e("TaskReturn", "Task Return!");
    if (intent.hasExtra(EXTRA_TASK_ID))
    {
        int taskToStart = intent.getIntExtra(EXTRA_TASK_ID, -1);
        Log.e("TaskReturn", "Returning To Task: " + taskToStart);
        ActivityManager activityManager = (ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);
        List<ActivityManager.AppTask> allAppTasks = activityManager.getAppTasks();

        for (ActivityManager.AppTask task : allAppTasks)
        {
            Log.e("TaskReturn", "AllTasks: " + task.getTaskInfo().id + " " + task.getTaskInfo().affiliatedTaskId + " " + task.getTaskInfo().persistentId);
        }

        activityManager.moveTaskToFront(taskToStart, ActivityManager.MOVE_TASK_WITH_HOME);
    }
    else
    {
        Log.e("TaskReturn", "WHERE IS MY EXTRA!?!?!");
        //Boo...
    }
}

---

---

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

...

...

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

Basically the idea is that you mark the result of a call to Activity.getTaskId() to the state. Later, when creating a notification to resume to that activity's task, grab the task ID and throw it into an extra. Then, set the pending intent to point to a broadcast receiver that pulls out the task id and fires up that task.

基本上这个想法是将调用 Activity.getTaskId() 的结果标记为状态。稍后，在创建通知以恢复该活动的任务时，获取任务 ID 并将其放入额外的。然后，将挂起的意图设置为指向一个广播接收器，该接收器拉出任务 id 并启动该任务。

Looks like this requires API 21 with the calls I used, and I suspect it might need some additional error checks if the task has already been quit, but it serves my purposes.

看起来这需要 API 21 和我使用的调用，如果任务已经退出，我怀疑它可能需要一些额外的错误检查，但它符合我的目的。