Merge pull request #401 from tink2123/add_android_doc

polish android readme

doc/doc_ch/android_demo.md

+# Android Demo 快速测试
+
+
+### 1. 安装最新版本的Android Studio
+
+可以从 https://developer.android.com/studio 下载。本Demo使用是4.0版本Android Studio编写。
+
+### 2. 创建新项目
+
+Demo测试的时候使用的是NDK 20b版本，20版本以上均可以支持编译成功。
+
+如果您是初学者，可以用以下方式安装和测试NDK编译环境。
+点击 File -> New ->New Project，  新建  "Native C++" project
+
+
+1. Start a new Android Studio project
+    在项目模版中选择 Native C++ 选择PaddleOCR/depoly/android_demo 路径
+    进入项目后会自动编译，第一次编译会花费较长的时间，建议添加代理加速下载。
+
+**代理添加：**
+
+选择 Android Studio -> Perferences -> Appearance & Behavior -> System Settings -> HTTP Proxy -> Manual proxy configuration
+
+![](../demo/proxy.png)
+
+2. 开始编译
+
+点击编译按钮，连接手机，跟着Android Studio的引导完成操作。
+
+在 Android Studio 里看到下图，表示编译完成：
+
+![](../demo/build.png)
+
+**提示:** 此时如果出现下列找不到OpenCV的报错信息，请重新点击编译，编译完成后退出项目，再次进入。
+
+![](../demo/error.png)
+
+### 3. 发送到手机端
+
+完成编译，点击运行，在手机端查看效果。
+
+### 4. 如何自定义demo图片
+
+1. 图片存放路径:android_demo/app/src/main/assets/images
+
+   将自定义图片放置在该路径下
+
+2. 配置文件: android_demo/app/src/main/res/values/strings.xml
+
+   修改 IMAGE_PATH_DEFAULT 为自定义图片名即可
+
+
+# 获得更多支持
+前往[端计算模型生成平台EasyEdge](https://ai.baidu.com/easyedge/app/open_source_demo?referrerUrl=paddlelite)，获得更多开发支持：
+
+- Demo APP：可使用手机扫码安装，方便手机端快速体验文字识别
+- SDK：模型被封装为适配不同芯片硬件和操作系统SDK，包括完善的接口，方便进行二次开发

doc/doc_en/android_demo_en.md

+# Android Demo quick start
+
+### 1. Install the latest version of Android Studio
+
+It can be downloaded from https://developer.android.com/studio . This Demo is written by Android Studio version 4.0.
+
+### 2. Create a new project
+
+The NDK version 20b is used in the demo test, and the compilation can be successfully supported for version 20 and above.
+
+If you are a beginner, you can install and test the NDK compilation environment in the following ways.
+
+File -> New ->New Project  to create  "Native C++" project
+
+1. Start a new Android Studio project
+
+   Select Native C++ in the project template, select Paddle OCR/deploy/android_demo path
+   After entering the project, it will be automatically compiled. The first compilation
+   will take a long time. It is recommended to add an agent to speed up the download.
+
+**Agent add:**
+
+  Android Studio -> Perferences -> Appearance & Behavior -> System Settings -> HTTP Proxy -> Manual proxy configuration
+
+![](../demo/proxy.png)
+
+2. Start compilation
+
+Click the compile button, connect the phone, and follow the instructions of Android Studio to complete the operation.
+
+When you see the following picture in Android Studio, the compilation is complete:
+
+![](../demo/build.png)
+
+**Tip:** At this time, if the following error message that OpenCV cannot be found appears, please re-click compile,
+exit the project after compiling, and enter again.
+
+![](../demo/error.png)
+
+### 3. Send to mobile
+
+Complete the compilation, click Run, and check the effect on the mobile phone.
+
+### 4. How to customize the demo picture
+
+1. Image storage path: android_demo/app/src/main/assets/images
+
+   Place the custom picture under this path
+
+2. Configuration file: android_demo/app/src/main/res/values/strings.xml
+
+   Modify IMAGE_PATH_DEFAULT to a custom picture name
+
+# Get more support
+
+Go to [EasyEdge](https://ai.baidu.com/easyedge/app/open_source_demo?referrerUrl=paddlelite) to get more development support:
+
+- Demo APP: You can use your mobile phone to scan the code to install, which is convenient for the mobile terminal to quickly experience text recognition
+
+- SDK: The model is packaged to adapt to different chip hardware and operating system SDKs, including a complete interface to facilitate secondary development