（三十一）工具方法：获得应用程序包名/安装apk/如何获得当前栈顶的Activity/android如何实现点击一个按钮进入指定网页

/**
     * 获取当前应用程序的版本号
     * 
     * @return
     */
    private String getVersion() {
        try {
            PackageManager manager = getPackageManager(); // 获取包管理服务
            PackageInfo ClientInfo = manager
                    .getPackageInfo(getPackageName(), 0); // 获取包的信息

            return ClientInfo.versionName;
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return "版本号未知";
        }
    }

/**
     * 安装apk
     * 
     * @param file
     */
    private void install(File file) {

        Intent intent = new Intent();
        intent.setAction(Intent.ACTION_VIEW);
        intent.setDataAndType(Uri.fromFile(file),
                "application/vnd.android.package-archive");
        finish();
        startActivity(intent);
    }

String get TopActivity(Activity context)

    {
        ActivityManager manager = (ActivityManager)context.getSystemService(ACTIVITY_SERVICE) ;
        List<RunningTaskInfo> runningTaskInfos = manager.getRunningTasks(1) ;
        if(runningTaskInfos != null)
            return (runningTaskInfos.get(0).topActivity).toString() ;
        else
            return null ;
    }
    

最后不要忘记在AndroidManifest.xml中增加权限：

<uses-permission android:name = “android.permission.GET_TASKS”/>

Uri uri = Uri.parse("http://www.baidu.com");
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);