Launch an activity of an application from a different application on Android

问题

I need to launch an activity (not the main activity) of an application from an application I have made. The activity I want to launch is proprietary, hence, I cannot make any changes to its code(or manifest).

For example: I want to launch somebody's Facebook profile from my own application. A normal intent to facebook from my app would open the 'newsfeed'(which I don't want). I want to know how to access any other activity. Thanks in advance!

The little code I have:

String PACKAGE="com.facebook.katana";
Intent launchIntent = getPackageManager()
                    .getLaunchIntentForPackage(PACKAGE);
startActivity(launchIntent);

回答1:

To launch specific activity you need to use explicit intent. Or use implicit intent with action if you know what action that activity answers to.

To use explicit intent you can do the following (provided you call it from the activity):

        Intent intent = new Intent();
        intent.setComponent(new ComponentName("com.package.name", "com.package.name.ActivityName"));
        if(getPackageManager().resolveActivity(intent, 0) != null) {
            startActivity(intent);
        } else {
            Toast.makeText(this, "No app installed that can perform this action", Toast.LENGTH_SHORT).show();
        }

You can also add flags to the intent, add actions and categories. As long as the intent can be resolved as viable intent by the PackageManager, it will launch the activity.

Now...

The question about facebook profile, is a different one.

Perhaps, the best way to achieve that would be to use intent with action VIEW and povide Intent.setData with uri to the profile page. That should also be checked for possibility of being resolved correctly. And then will launch the chooser of all supported activities to open it, which should include facebook application. It is then up to user to open the intent using Facebook app or launcher.

来源：https://stackoverflow.com/questions/37978753/launch-an-activity-of-an-application-from-a-different-application-on-android