问如何以编程方式检查应用程序是否已安装在Android中？

EN

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Add respective layout
        setContentView(R.layout.main_activity);

        // Use package name which we want to check
        boolean isAppInstalled = appInstalledOrNot("com.check.application");  
        
        if(isAppInstalled) {
            //This intent will help you to launch if the package is already installed
            Intent LaunchIntent = getPackageManager()
                .getLaunchIntentForPackage("com.check.application");
            startActivity(LaunchIntent);
                    
            Log.i("SampleLog", "Application is already installed.");          
        } else {
            // Do whatever we want to do if application not installed
            // For example, Redirect to play store

            Log.i("SampleLog", "Application is not currently installed.");
        }
    }

    private boolean appInstalledOrNot(String uri) {
        PackageManager pm = getPackageManager();
        try {
            pm.getPackageInfo(uri, PackageManager.GET_ACTIVITIES);
            return true;
        } catch (PackageManager.NameNotFoundException e) {
        }

        return false;
    }

}

public static boolean isAppInstalled(Context context, String packageName) {
    try {
        context.getPackageManager().getApplicationInfo(packageName, 0);
        return true;
    }
    catch (PackageManager.NameNotFoundException e) {
        return false;
    }
}

boolean whatsappFound = AndroidUtils.isAppInstalled(context, "com.whatsapp");

private boolean isCallable(Intent intent) {  
        List<ResolveInfo> list = getPackageManager().queryIntentActivities(intent,   
        PackageManager.MATCH_DEFAULT_ONLY);  
        return list.size() > 0;  
}