Android 通过包名或类名启动APP

private void doStartApplicationWithPackageName(String packagename) {

        // 通过包名获取此APP详细信息，包括Activities、services、versioncode、name等等
        PackageInfo packageinfo = null;
        try {
            packageinfo = mContext.getPackageManager().getPackageInfo("你项目的包名", 0);
            Log.e("==包名==",packageinfo.toString());
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        if (packageinfo == null) {
            return;
        }

        // 创建一个类别为CATEGORY_LAUNCHER的该包名的Intent
        Intent resolveIntent = new Intent(Intent.ACTION_MAIN, null);
        resolveIntent.addCategory(Intent.CATEGORY_LAUNCHER);
        resolveIntent.setPackage(packageinfo.packageName);

        // 通过getPackageManager()的queryIntentActivities方法遍历
        List<ResolveInfo> resolveinfoList = mContext.getPackageManager()
                .queryIntentActivities(resolveIntent, 0);

        ResolveInfo resolveinfo = resolveinfoList.iterator().next();
        if (resolveinfo != null) {
            // packagename = 参数packname
            String packageName = resolveinfo.activityInfo.packageName;
            // 这个就是我们要找的该APP的LAUNCHER的Activity[组织形式：packagename.mainActivityname]
            String className = resolveinfo.activityInfo.name;
            // LAUNCHER Intent
            Intent intent = new Intent(Intent.ACTION_MAIN);
            intent.addCategory(Intent.CATEGORY_LAUNCHER);

            // 设置ComponentName参数1:packagename参数2:MainActivity路径
            ComponentName cn = new ComponentName(packageName, className);

            intent.setComponent(cn);
            mContext.startActivity(intent);
        }
    }