我觉得这个问题说明了一切：什么是找出如果用户已经在他的手机安装了Facebook或WhatsApp的最好方法是什么？我必须走了过来包或什么是最好的方法？

I think the question says it all: What is the best way to find out if the user has installed Facebook or Whatsapp on his phone? Do I have to go over the package or what is the best way for this?

推荐答案

这是问题得到回答here.您可以使用下面这段code检查包名

This was question was answered here. You can using the following piece of code to check for the package name

com.facebook.android或com.facebook.katana

com.facebook.android OR com.facebook.katana

code：

public class Example extends Activity
    {
        @Override
        protected void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            //Put the package name here...
            boolean installed  =   appInstalledOrNot("com.facebook.android");  
            if(installed)
            {
            //This intent will help you to launch if the package is already installed
            Intent LaunchIntent = getPackageManager()
                .getLaunchIntentForPackage("com.facebook.android");
        startActivity(LaunchIntent);


                      System.out.println("App already installed om your phone");


            }
            else
            {
                System.out.println("App is not installed om your phone");
            }
        }
        private boolean appInstalledOrNot(String uri)
        {
            PackageManager pm = getPackageManager();
            boolean app_installed = false;
            try
            {
                   pm.getPackageInfo(uri, PackageManager.GET_ACTIVITIES);
                   app_installed = true;
            }
            catch (PackageManager.NameNotFoundException e)
            {
                   app_installed = false;
            }
            return app_installed ;
    }
    }