android 背景水印,Android 给View添加重复的文字水印背景 类似钉钉通讯录的背景效果...

先看效果：

先说实现方式：

1、首先先用文字创建一个Bitmap 图片。

Bitmap bitmap = Bitmap.createBitmap(420, 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(0, 150);

path.lineTo(160 * 2, 0);

canvas.drawTextOnPath(gText, path, 0, 20, paint);

canvas.save(Canvas.ALL_SAVE_FLAG);

canvas.restore();

bitmap.recycle();在一个空白的背景上画出文字内容，此处的通过设置一个斜向上的path，然后在这个path上写文字，生成一个斜向上方形的文字。

最后得到一个Bitmap.

2、将生成的bitmap 一个view上

BitmapDrawable drawable = new BitmapDrawable(bitmap);

drawable.setTileModeXY(Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);

drawable.setDither(true);

view.setBackgroundDrawable(drawable );

最后贴上工具类代码：如果只想要背景图片 用drawTextToBitmap(), 如果要直接给一个view设置上背景 直接使用setWaterMarkTextBg()方法。

public class WaterMarkTextUtil {

//设置背景

public void setWaterMarkTextBg(View view, Context gContext, String gText) {

view.setBackgroundDrawable(drawTextToBitmap(gContext, gText));

}

/**

* 生成水印文字图片

*/

public BitmapDrawable drawTextToBitmap(Context gContext, String gText) {

gText=gText+" daydao";

if (ACache.get(gContext).getAsBitmap(gText) != null) {

BitmapDrawable drawable = new BitmapDrawable(ACache.get(gContext).getAsBitmap(gText));

drawable.setTileModeXY(Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);

drawable.setDither(true);

return drawable;

}

try {

Bitmap bitmap = Bitmap.createBitmap(420, 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(0, 150);

path.lineTo(160 * 2, 0);

canvas.drawTextOnPath(gText, path, 0, 20, paint);

canvas.save(Canvas.ALL_SAVE_FLAG);

canvas.restore();

ACache.get(gContext).put(gText, bitmap);

BitmapDrawable drawable = new BitmapDrawable(bitmap);

drawable.setTileModeXY(Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);

drawable.setDither(true);

bitmap.recycle();

return drawable;

} catch (Exception e) {

}

return null;

}

}