记录一次水印背景的简单实现
效果图.png
1.自定义参数
2.自定义控件
package 你的包名.weight;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import 你的包名.R;
/**
* Des: 自定义水印View
* Created by kele on 2020/11/12.
* E-mail:[email protected]
*/
public class WaterMarkView extends View {
private static final String TAG = WaterMarkView.class.getSimpleName();
private int mDrawWidth = 300;//画的宽度 为实际高度的mScaleSize倍（作用是在旋转后防止有些地方没有水印）
private int mDrawHeight = 300;//画的高度 同上
private String str = "可乐";//水印文字
private float hSpace = 50f;//水平间距
private float vSpace = 20f;//垂直间距
private int mScaleSize = 2;//缩放大小 固定：2
private int mDegrees = -30;//旋转角度
private int bgColor = Color.TRANSPARENT;//背景颜色
private int textColor = Color.BLACK;//字体颜色
private float textSize = 13f;//字体大小
private int mWidth;//布局实际宽度
private int mHeight;//布局实际高度
public WaterMarkView(@NonNull Context context) {
this(context, null);
}
public WaterMarkView(@NonNull Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init(context, attrs);
}
/**
* 初始化
*
* @param context
* @param attrs
*/
public void init(Context context, AttributeSet attrs) {
if (null != attrs) {
//获取XML中的参数
TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.WaterMarkView);
str = ta.getString(R.styleable.WaterMarkView_text);
hSpace = ta.getDimension(R.styleable.WaterMarkView_hSpace, 50f);
vSpace = ta.getDimension(R.styleable.WaterMarkView_vSpace, 20f);
mDegrees = ta.getInteger(R.styleable.WaterMarkView_degrees, -30);
bgColor = ta.getColor(R.styleable.WaterMarkView_bgColor, Color.TRANSPARENT);
textColor = ta.getColor(R.styleable.WaterMarkView_textColor, Color.BLACK);
textSize = ta.getDimension(R.styleable.WaterMarkView_textSize, 13f);
ta.recycle();
}
}
/**
* 设置参数
*
* @param text 水印文字
*/
public void setParams(String text) {
setParams(text, hSpace, vSpace);
}
/**
* 设置参数
*
* @param text 水印文字
* @param hSize 水平方向水印文字个数
* @param vSize 垂直方向水印文字个数
*/
public void setParams(String text, float hSize, float vSize) {
setParams(text, hSize, vSize, mDegrees);
}
/**
* 设置参数
*
* @param text 水印文字
* @param hSize 水平方向水印文字个数
* @param vSize 垂直方向水印文字个数
* @param degrees 旋转角度
*/
public void setParams(String text, float hSize, float vSize, int degrees) {
setParams(text, hSize, vSize, degrees, bgColor, textColor, textSize);
}
/**
* 参数设置
*
* @param text
* @param hSize
* @param vSize
* @param degrees
* @param bgColor 背景颜色
* @param textColor 字体颜色
* @param textSize 字体大小
*/
public void setParams(String text, float hSize, float vSize, int degrees, int bgColor, int textColor, float textSize) {
this.str = text;
this.hSpace = hSize;
this.vSpace = vSize;
this.mDegrees = degrees;
this.bgColor = bgColor;
this.textColor = textColor;
this.textSize = textSize;
invalidate();
}
/**
* 在View的源码当中并没有对AT_MOST和EXACTLY两个模式做出区分，
* 也就是说View在wrap_content和match_parent两个模式下是完全相同的，
* 都会是match_parent，
* 显然这与我们平时用的View不同，
* 所以我们要重写onMeasure方法。
*
* @param widthMeasureSpec
* @param heightMeasureSpec
*/
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
if (widthMode == MeasureSpec.AT_MOST && heightMode == MeasureSpec.AT_MOST) {
setMeasuredDimension(mDrawWidth, mDrawHeight);
} else if (widthMode == MeasureSpec.AT_MOST) {
setMeasuredDimension(mDrawWidth, heightSize);
} else if (heightMode == MeasureSpec.AT_MOST) {
setMeasuredDimension(widthSize, mDrawHeight);
}
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
//获取实际宽高
mWidth = getWidth();
mHeight = getHeight();
//设置需要画的宽高
mDrawWidth = mWidth * mScaleSize;
mDrawHeight = mHeight * mScaleSize;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//画水印
drawWaterMark(canvas);
}
/**
* 绘制水印
*
* @param canvas
*/
private void drawWaterMark(Canvas canvas) {
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
Rect rect = new Rect();
paint.setTextSize(textSize);
//获取文字长度和宽度
paint.getTextBounds(str, 0, str.length(), rect);
int textWidth = rect.width();
int textHeight = rect.height();
//获取每个单独的item的宽高
float itemWidth = textWidth + hSpace;
float itemHeight = textHeight + vSpace;
//获取水平、垂直方向需要绘制的个数
int hSize = (int) ((mDrawWidth / itemWidth) + 0.5);
int vSize = (int) ((mDrawHeight / itemHeight) + 0.5);
//X轴开始坐标
float xStart = hSpace / 2;
//Y轴开始坐标
float yStart = vSpace / 2 + textHeight;
//创建透明画布
canvas.drawColor(bgColor);
paint.setColor(textColor);
//paint.setAlpha((int) (0.1 * 255));
// 获取跟清晰的图像采样
paint.setDither(true);
paint.setFilterBitmap(true);
canvas.save();
//平移
canvas.translate(-(mDrawWidth / 4), -(mDrawHeight / 4));
//旋转对应角度
canvas.rotate(mDegrees, mDrawWidth / 2, mDrawHeight / 2);
//画X轴方向
for (int i = 0; i < hSize; i++) {
float xDraw = xStart + itemWidth * i;
//画Y轴方向
for (int j = 0; j < vSize; j++) {
float yDraw = yStart + itemHeight * j;
canvas.drawText(str, xDraw, yDraw, paint);
}
}
canvas.restore();
}
}
3.使用（以xml中使用为例）
xml:
<你的包名.weight.WaterMarkView
android:id="@+id/wmv"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:bgColor="@color/color_F4F4F4"
app:text="可乐"
app:hSpace="@dimen/dp_30"
app:vSpace="@dimen/dp_30"
app:degrees="-30"
app:textColor="@color/color_E6E8EC"
app:textSize="@dimen/sp_13" />
java:
WaterMarkView wmv = v.findViewById(R.id.wmv);
wmv.setParams("小可乐");
-
基于ViewGroup实现类似，详见github
GitHub地址：https://github.com/xiaokele/WaterMarkView