Android 保存图片到相册

废话不多说，先上效果：

点击图片 调用savephoto的SaveBitmapFromView(View view);方法自动保存图片

//点击图片保存
imageView.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        String[] PERMISSIONS = {
                "android.permission.READ_EXTERNAL_STORAGE",
                "android.permission.WRITE_EXTERNAL_STORAGE" };
        //检测是否有写的权限
        int permission = ContextCompat.checkSelfPermission(MainActivity.this,
                "android.permission.WRITE_EXTERNAL_STORAGE");
        if (permission != PackageManager.PERMISSION_GRANTED) {
            // 没有写的权限，去申请写的权限，会弹出对话框
            ActivityCompat.requestPermissions(MainActivity.this, PERMISSIONS,1);
        }
        try {
            //创建savephoto类保存图片
            SavePhoto savePhoto = new SavePhoto(MainActivity.this);
            savePhoto.SaveBitmapFromView(imageView);
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }
});

SavePhoto类具体实现
参考自：https://blog.csdn.net/QingSheng33/article/details/78738281
但原博主部分代码有误 我稍加了修改

public class SavePhoto{
    //存调用该类的活动
    Context context;

    public SavePhoto(Context context) {
        this.context = context;
    }

    //保存文件的方法：
    public void SaveBitmapFromView(View view) throws ParseException {
        int w = view.getWidth();
        int h = view.getHeight();
        Bitmap bmp = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(bmp);
        view.layout(0, 0, w, h);
        view.draw(c);
        // 缩小图片
        Matrix matrix = new Matrix();
        matrix.postScale(0.5f,0.5f); //长和宽放大缩小的比例
        bmp = Bitmap.createBitmap(bmp,0,0,bmp.getWidth(),bmp.getHeight(),matrix,true);
        DateFormat format = new SimpleDateFormat("yyyyMMddHHmmss");
        saveBitmap(bmp,bmp.toString() + ".JPEG");
    }

    /*
     * 保存文件，文件名为当前日期
     */
    public void saveBitmap(Bitmap bitmap, String bitName){
        String fileName ;
        File file ;
        if(Build.BRAND .equals("Xiaomi") ){ // 小米手机
            fileName = Environment.getExternalStorageDirectory().getPath()+"/DCIM/Camera/"+bitName ;
        }else{  // Meizu 、Oppo
            Log.v("qwe","002");
            fileName = Environment.getExternalStorageDirectory().getPath()+"/DCIM/"+bitName ;
        }
        file = new File(fileName);

        if(file.exists()){
            file.delete();
        }
        FileOutputStream out;
        try{
            out = new FileOutputStream(file);
            // 格式为 JPEG，照相机拍出的图片为JPEG格式的，PNG格式的不能显示在相册中
            if(bitmap.compress(Bitmap.CompressFormat.JPEG, 90, out))
            {
                out.flush();
                out.close();
                // 插入图库
                MediaStore.Images.Media.insertImage(context.getContentResolver(), file.getAbsolutePath(), bitName, null);

            }
        }
        catch (FileNotFoundException e)
        {
            e.printStackTrace();
        }
        catch (IOException e)
        {
            e.printStackTrace();

        }
        // 发送广播，通知刷新图库的显示
        context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + fileName)));

    }
}

布局于其他部分（GridView选择图片等）代码：

https://blog.csdn.net/qq_43377749/article/details/84325754
**另附：**从相册中选择图片的方法
https://blog.csdn.net/qq_43377749/article/details/84147422