判斷應用是否安裝有兩種方式：

根據報名判斷

public boolean checkApkExist(Context context, String packageName) {    
if (packageName == null ||"".equals(packageName))
        return false;   
 try {       
 ApplicationInfo info = context.getPackageManager().getApplicationInfo(packageName, PackageManager.GET_UNINSTALLED_PACKAGES);
        return true;    
} catch (PackageManager.NameNotFoundException e) { 
       return false;    
}
}

根據Intent判斷

public boolean checkApkExist(Intent intent) {    
List<ResolveInfo> list = this.getPackageManager().queryIntentActivities(intent, 0); 
   if (list.size() > 0) {  
      return true;    
}   
 return false;
}