PackageManager packageManager = getPackageManager();
String packname="";//此處為包名
 if (checkPackInfo(packname)) {//檢查是否有要開啟的app
     Intent intent = packageManager.getLaunchIntentForPackage(packname);
     startActivity(intent);
 } else {
     launchAppDetail(packname,"");//跳轉到應用市場
 }

/**
 * 檢查包是否存在
 *
 * 
 
@param packname
* @return
*/
private boolean checkPackInfo(String packname) {
    PackageInfo packageInfo = null;
    try {
        packageInfo = getPackageManager().getPackageInfo(packname, 0);
    } catch (PackageManager.NameNotFoundException e) {
        e.printStackTrace();
    }
    return packageInfo != null
 
;
}

/**
     * 啟動到應用商店app詳情介面
     *
     * @param appPkg    目標App的包名
     * @param marketPkg 應用商店包名 ,如果為""則由系統彈出應用商店列表供使用者選擇,否則調轉到目標市場的應用詳情介面，某些應用商店可能會失敗
     */
public void launchAppDetail(String appPkg, String marketPkg) {
        try {
            if (TextUtils.isEmpty(appPkg)) return;

            Uri uri = Uri.parse
 
("market://details?id=" + appPkg);
            Intent intent = new Intent(Intent.ACTION_VIEW, uri);
            if (!TextUtils.isEmpty(marketPkg)) {
                intent.setPackage(marketPkg);
            }
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(intent);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

另外附加以為大神的關於該功能的文章地址：http://www.jianshu.com/p/42ae7066f8f3