Android图片添加水印图片并把图片保存到文件存储

package zhangphil.test;import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.os.Bundle;
import android.os.Environment;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.view.View;import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;public class JavaActivity extends AppCompatActivity {@Overrideprotected void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.drawable_activity);findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {add();}});}private void add() {new Thread(new Runnable() {@Overridepublic void run() {File zhang = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "zhang.jpg");try {//原图片。Bitmap bitmap1 = BitmapFactory.decodeStream(new FileInputStream(zhang));//水印图。Bitmap bitmap2 = BitmapFactory.decodeResource(getResources(), R.drawable.logo);//原图片添加水印后形成新的文件。File zhangphil = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "zhangphil.jpg");if (!zhangphil.exists())zhangphil.createNewFile();//原图片添加水印后形成的新Bitmap。在原图片的最左边和做顶部开始添加。//如果是中间或者底部需要计算x,y的坐标位置。Bitmap newbitmap = addImageWatermark(bitmap1, bitmap2, 0, 0);//把添加水印后的Bitmap保存到文件。save(newbitmap, zhangphil, Bitmap.CompressFormat.JPEG, true);} catch (Exception e) {e.printStackTrace();}}}).start();}/*** 添加图片水印。** @param src       源图片* @param watermark 图片水印* @param x         起始坐标x* @param y         起始坐标y* @return 带有图片水印的图片*/public static Bitmap addImageWatermark(Bitmap src, Bitmap watermark, int x, int y) {Bitmap retBmp = src.copy(src.getConfig(), true);Canvas canvas = new Canvas(retBmp);canvas.drawBitmap(watermark, x, y, null);return retBmp;}/*** 保存图片到文件File。** @param src     源图片* @param file    要保存到的文件* @param format  格式* @param recycle 是否回收* @return true 成功 false 失败*/public static boolean save(Bitmap src, File file, Bitmap.CompressFormat format, boolean recycle) {if (isEmptyBitmap(src))return false;OutputStream os;boolean ret = false;try {os = new BufferedOutputStream(new FileOutputStream(file));ret = src.compress(format, 100, os);if (recycle && !src.isRecycled())src.recycle();} catch (IOException e) {e.printStackTrace();}return ret;}/*** Bitmap对象是否为空。*/public static boolean isEmptyBitmap(Bitmap src) {return src == null || src.getWidth() == 0 || src.getHeight() == 0;}
}

事先需要先放好源图片Pictures/zhang.jpg和水印图片res/drawable/logo.jpg。

权限：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />