前言

1. 概述

首先先来实现一个简单的需求，给网络图片添加水印。分别用一般的Java代码 和 RxJava写法来实现，下边先用一般 Java代码实现。

2. 流程图如下：

网络图片添加水印一般写法与RxJava写法.png

3. 效果如下

图片.png

4. 代码如下：

/**

* Email: 2185134304@qq.com

* Created by Novate 2018/6/23 11:29

* Version 1.0

* Params:

* Description: 网络图片加载水印一般写法

*/

public class MainActivity extends AppCompatActivity {

private ImageView iv;

private Handler handler = new Handler(){

@Override

public void handleMessage(Message msg) {

Bitmap bitmap = (Bitmap)msg.obj;

iv.setImageBitmap(bitmap);

}

} ;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

iv = (ImageView) findViewById(R.id.iv);

// 网络图片加水印一般写法

new Thread(new Runnable() {

@Override

public void run() {

try {

// 创建url地址

URL url = new URL("http://img.taopic.com/uploads/allimg/130331/240460-13033106243430.jpg") ;

// 建立连接

HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

// 获取输入流

InputStream inputStream = urlConnection.getInputStream();

// 把流转为bitmap

Bitmap bitmap = BitmapFactory.decodeStream(inputStream);

// 加一个水印

bitmap = createWatermark(bitmap , "RxJava2.0") ;

// 显示到ImageView上边

Message msg = Message.obtain() ;

msg.obj = bitmap ;

handler.sendMessage(msg) ;

} catch (Exception e) {

e.printStackTrace();

}

}

}).start();

}

private Bitmap createWatermark(Bitmap bitmap, String mark) {

int w = bitmap.getWidth();

int h = bitmap.getHeight();

Bitmap bmp = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(bmp);

Paint p = new Paint();

// 水印颜色

p.setColor(Color.parseColor("#C5FF0000"));

// 水印字体大小

p.setTextSize(150);

//抗锯齿

p.setAntiAlias(true);

//绘制图像

canvas.drawBitmap(bitmap, 0, 0, p);

//绘制文字

canvas.drawText(mark, 0, h / 2, p);

canvas.save(Canvas.ALL_SAVE_FLAG);

canvas.restore();

return bmp;

}

}