android - android中同一应用程序的多个实例

Question

如何在从图库应用程序内部共享图像时使用已经运行的应用程序？ 它总是在创建已经运行的应用程序的单独实例。 我在 whatsapp 应用程序中观察到同样的问题。

Answer 1

是的。另一个用例是当您点击通知时。如果应用程序已经在后台，它将启动一个新实例。

使用 android:launchMode

<activity android:launchMode = ["standard" | "singleTop" | "singleTask" | "singleInstance"] ../>

所以使用 "singleTop"

来自 the docs :

If an instance of the activity already exists at the top of the current task, the system routes the intent to that instance through a call to its onNewIntent() method, rather than creating a new instance of the activity. The activity can be instantiated multiple times, each instance can belong to different tasks, and one task can have multiple instances (but only if the activity at the top of the back stack is not an existing instance of the activity).

请阅读下面的博文

http://inthecheesefactory.com/blog/understand-android-activity-launchmode/en

https://www.mobomo.com/2011/06/android-understanding-activity-launchmode/

已编辑:在 OnResume 之前，它会调用 OnActivityResult。使用已选择的数据。

Intent intent = new Intent();

    intent.setType("image/jpeg");
            intent.setAction(Intent.ACTION_GET_CONTENT);

            startActivityForResult(Intent.createChooser(intent,
                    "Select Image From Gallery"),
                    10000);


    @Override
        protected void onActivityResult(final int requestCode, final int resultCode, final Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
Uri originalUri = null;
        if (resultCode == Activity.RESULT_OK) {
    if (requestCode == 10000) {
    
                    if (data.getData() != null) {
                        originalUri = data.getData();
                        //originaluri is your selected image path.
            
    
                    }}}

并在我们的应用中获取 Intent Filter Action。

void onCreate (Bundle savedInstanceState) {
    ...
    // Get intent, action and MIME type
    Intent intent = getIntent();
    String action = intent.getAction();
    String type = intent.getType();

    if (Intent.ACTION_SEND.equals(action) && type != null) {
        if ("text/plain".equals(type)) {
            handleSendText(intent); // Handle text being sent
        } else if (type.startsWith("image/")) {
            handleSendImage(intent); // Handle single image being sent
        }
    } 

http://developer.android.com/training/sharing/receive.html http://developer.android.com/training/basics/intents/filters.html

或者如果您使用的是启动模式-singleTop。只需覆盖 onNewIntent。

 @Override
    protected void onNewIntent(Intent intent) {


        super.onNewIntent(intent);
       
    }