Android

Android中添加背景水印，含WebView

绝密资料，必须加上水印背景以免外传，在Android中如何实现呢？分为普通背景水印和加载网页中添加水印。当然网页本身可以直接加，WebView加载下来直接就有了，这种方案我们不讨论，只讨论在WebView中追加。
先上效果图：
普通背景水印
普通背景水印
网页水印

网页水印

普通背景水印

创建一个水印Bitmap，为rootView设置背景。so easy,直接上代码 

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@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_watermark);
  if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.JELLY_BEAN) {
    findViewById(android.R.id.content).setBackground(background("水印"));
  }else{
    findViewById(android.R.id.content).setBackgroundDrawable(background("水印"));
  }
}
BitmapDrawable background(String watermark){
  Bitmap bitmap = Bitmap.createBitmap(240, 240, Bitmap.Config.ARGB_8888);
  Canvas canvas = new Canvas(bitmap);
  canvas.drawColor(Color.WHITE);
  Paint paint = new Paint();
  paint.setColor(Color.GRAY);
  paint.setAlpha(80);
  paint.setAntiAlias(true);
  paint.setTextAlign(Paint.Align.LEFT);
  paint.setTextSize(40);
  Path path = new Path();
  path.moveTo(30, 150);
  path.lineTo(300, 0);
  canvas.drawTextOnPath(watermark, path, 0, 30, paint);

  BitmapDrawable bitmapDrawable = new BitmapDrawable(bitmap);
  bitmapDrawable.setTileModeXY(Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);
  bitmapDrawable.setDither(true);
  return  bitmapDrawable;
}

网页水印

网页背景水印
在网页加载完成后插入javascript添加div水印

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String addWaterMarker(String watermark) {
    String js = "var newscript = document.createElement(\"script\");";
    js += "var bbTextNode = document.createTextNode(\"";
    js += "var can = document.createElement('canvas');";
    js +=
        "var body = document.body;body.appendChild(can);can.width=400; can.height=200;can.style.display='none';"
            + "var cans = can.getContext('2d');cans.rotate(-20*Math.PI/180);cans.font = '16px Microsoft JhengHei';"
            + "cans.fillStyle = 'rgba(17, 17, 17, 0.50)';cans.textAlign = 'left';"
            + "cans.textBaseline = 'Middle';cans.fillText('watermark',can.width/3,can.height/2);"
            + "body.style.backgroundImage='url('+can.toDataURL('image/png')+')';"
    ;
    js += "\");";
    js += "newscript.appendChild(bbTextNode);";
    js += "var t = document.createTextNode(\"alert('action');\");";
    js += "newscript.appendChild(t);";
    //js += "newscript.onload=function(){xxx();};";  //xxx()代表js中某方法
    js += "document.body.appendChild(newscript);";

    return js;
  }

  String addWaterMarkerDiv(String watermark) {
    String js = "var newscript = document.createElement(\"script\");";

    js += "var waterMarkDiv = document.createTextNode(\""
        //+"if(document.getElementById('waterMark') != null) return;"
        + "var m = 'waterMark';"
        + "var newMark = document.createElement('div');"
        + "newMark.id = m;"
        + "newMark.style.position = 'absolute';"
        + "newMark.style.zIndex = '9527';"
        + "newMark.style.top = '0px';"
        + "newMark.style.left = '0px';"
        + "newMark.style.width = '800px';"
        + "newMark.style.height = '400px';"
        + "alert('newmark');"
        + "\");"
    ;

    js += "newscript.appendChild(waterMarkDiv);";
    js += "var bbTextNode = document.createTextNode(\"";
    js += "var can = document.createElement('canvas');";
    js +=
        "var body = document.body;body.appendChild(can);can.width=400; can.height=200;can.style.display='none';"
            + "var cans = can.getContext('2d');cans.rotate(-20*Math.PI/180);cans.font = '16px Microsoft JhengHei';"
            + "cans.fillStyle = 'rgba(17, 17, 17, 0.50)';cans.textAlign = 'left';"
            + "cans.textBaseline = 'Middle';cans.fillText('watermark',can.width/3,can.height/2);"
            + "newMark.style.backgroundImage='url('+can.toDataURL('image/png')+')';"
            + "newMark.style.filter = 'alpha(opacity=50)';"
            + "document.body.appendChild(newMark);"
    ;
    js += "\");";
    js += "newscript.appendChild(bbTextNode);";
    js += "document.body.appendChild(newscript);";

    return js;
  }

完整demo例子

引用

【Android】webview javascript 注入方法
Javascript 网页水印(非图片水印)实现代码
html如何添加水印？