Android 判断app是否安装

1.

private boolean isAppInstalled(Context context, String uri) {
        PackageManager pm = context.getPackageManager();
        boolean installed = false;
        try {
            pm.getPackageInfo(uri, PackageManager.GET_ACTIVITIES);
            installed = true;
        } catch (PackageManager.NameNotFoundException e) {
            installed = false;
        }
        return installed;
    }  

2.

public boolean isAppInstalled(Context context, String packageName) {
        final PackageManager packageManager = context.getPackageManager();
        List<PackageInfo> pinfo = packageManager.getInstalledPackages();
        List<String> pName = new ArrayList<String>();
        if (pinfo != null) {
            for (int i = ; i < pinfo.size(); i++) {
                String pn = pinfo.get(i).packageName;
                pName.add(pn);
            }
        }
        return pName.contains(packageName);
    }  

例子：

                 if (isInstallApp(MainActivity.this, "com.xxx")) {
                    System.out.println("Installed!!");
                } else {
                    System.out.println("Not installed!!");
                }