1、图片缩略图类
android中提供了一个图片缩略图工具类：ThumbnailUtils，就拿里面的图片缩略图的方法来说说，使用上很简单：
//bitmap --> 要选择进行缩略的位图
//350--> 缩略图的宽
//120--> 缩略图的高
ThumbnailUtils.extractThumbnail(bitmap, 350, 120)
具体的源码如下：
/**
* Creates a centered bitmap of the desired size.//创建所需大小的中心位图。
*
* @param source original bitmap source
* @param width targeted width
* @param height targeted height
*/
public static Bitmap extractThumbnail(
Bitmap source, int width, int height) {
return extractThumbnail(source, width, height, OPTIONS_NONE);
}
/**
* Creates a centered bitmap of the desired size.
*
* @param source original bitmap source
* @param width targeted width
* @param height targeted height
* @param options options used during thumbnail extraction
*/
public static Bitmap extractThumbnail(
Bitmap source, int width, int height, int options) {
if (source == null) {
return null;
}
float scale;
if (source.getWidth() < source.getHeight()) {
scale = width / (float) source.getWidth();
} else {
scale = height / (float) source.getHeight();
}
Matrix matrix = new Matrix();
matrix.setScale(scale, scale);
Bitmap thumbnail = transform(matrix, source, width, height,
OPTIONS_SCALE_UP | options);
return thumbnail;
}
2、BitmapUtils工具类方法的收集
public class BitmapUtils {
/**
* 将base64转换成bitmap图片
* @param string base64字符串
* @return bitmap
*
*/
public static Bitmap stringToBitmap(String string) {
if (TextUtils.isEmpty(string)) {
return null;
}
// 将字符串转换成Bitmap类型
Bitmap bitmap = null;
try {
byte[] bitmapArray;
bitmapArray = Base64.decode(string, Base64.DEFAULT);
bitmap = BitmapFactory.decodeByteArray(bitmapArray, 0,
bitmapArray.length);
} catch (Exception e) {
e.printStackTrace();
}
return bitmap;
}
/**
* 将Bitmap照片保存到本地
* @param bitmap
* @param bitName
*/
public static String saveBitmap(Bitmap bitmap,String bitName)
{
String signPhotoPath = Environment.getExternalStorageDirectory( ) + "/DCIM/" + bitName + ".jpg";
File file = new File(signPhotoPath);
if(file.exists()){
file.delete();
}
FileOutputStream out;
try{
out = new FileOutputStream(file);
if(bitmap.compress(Bitmap.CompressFormat.PNG, 100, out)){
out.flush();
out.close();
}
}
catch (Exception e){
e.printStackTrace();
}
return signPhotoPath;
}
/**
* 按照一定的宽高比例裁剪图片
*
* @param bitmap
* @param num1
* 长边的比例
* @param num2
* 短边的比例
* @return
*/
public static Bitmap ImageCrop(Bitmap bitmap, int num1, int num2,
boolean isRecycled)
{
if (bitmap == null)
{
return null;
}
int w = bitmap.getWidth(); // 得到图片的宽，高
int h = bitmap.getHeight();
int retX, retY;
int nw, nh;
if (w > h)
{
if (h > w * num2 / num1)
{
nw = w;
nh = w * num2 / num1;
retX = 0;
retY = (h - nh) / 2;
} else
{
nw = h * num1 / num2;
nh = h;
retX = (w - nw) / 2;
retY = 0;
}
} else
{
if (w > h * num2 / num1)
{
nh = h;
nw = h * num2 / num1;
retY = 0;
retX = (w - nw) / 2;
} else
{
nh = w * num1 / num2;
nw = w;
retY = (h - nh) / 2;
retX = 0;
}
}
LogUtil.d("retX",retX+"");
LogUtil.d("retY",retY+"");
LogUtil.d("nw",nw+"");
LogUtil.d("nh",nh+"");
Bitmap bmp = Bitmap.createBitmap(bitmap, retX, retY, nw, nh, null,
false);
if (isRecycled && bitmap != null && !bitmap.equals(bmp)
&& !bitmap.isRecycled())
{
bitmap.recycle();
bitmap = null;
}
return bmp;// Bitmap.createBitmap(bitmap, retX, retY, nw, nh, null,
// false);
}
/**
* 质量压缩方法
* @param mBitmap
* @return
*/
public static Bitmap qualityCompressBitmap(Bitmap mBitmap) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
mBitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);//质量压缩方法，这里100表示不压缩，把压缩后的数据存放到baos中
int options = 100;
LogUtil.d("压缩前图片占内存大小（KB）====" + baos.toByteArray().length / 1024);
while ( baos.toByteArray().length / 1024>80) { //循环判断如果压缩后图片是否大于100kb,大于继续压缩
baos.reset();//重置baos即清空baos
mBitmap.compress(Bitmap.CompressFormat.JPEG, options, baos);//这里压缩options%，把压缩后的数据存放到baos中
options -= 10;//每次都减少10
LogUtil.d("压缩后图片占内存大小（KB）" + baos.toByteArray().length / 1024);
}
if ( !mBitmap.isRecycled()){
mBitmap.recycle();
mBitmap = null;
System.gc();
}
ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());//把压缩后的数据baos存放到ByteArrayInputStream中
Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, null);//把ByteArrayInputStream数据生成图片
return bitmap;
}
/**
* 图片按比例大小压缩方法（根据Bitmap图片压缩）
* @param mBitmap
* @return
*/
public static Bitmap proportionCompressBitmap(Bitmap mBitmap) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
mBitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
if( baos.toByteArray().length / 1024 > 80) {//判断如果图片大于1M,进行压缩避免在生成图片（BitmapFactory.decodeStream）时溢出
baos.reset();//重置baos即清空baos
mBitmap.compress(Bitmap.CompressFormat.JPEG, 50, baos);//这里压缩50%，把压缩后的数据存放到baos中
}
ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());
BitmapFactory.Options newOpts = new BitmapFactory.Options();
//开始读入图片，此时把options.inJustDecodeBounds 设回true了
newOpts.inJustDecodeBounds = true;
Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, newOpts);
newOpts.inJustDecodeBounds = false;
int w = newOpts.outWidth;
int h = newOpts.outHeight;
//现在主流手机比较多是800*480分辨率，所以高和宽我们设置为
float hh = 480f;//这里设置高度为800f
float ww = 640f;//这里设置宽度为480f
//缩放比。由于是固定比例缩放，只用高或者宽其中一个数据进行计算即可
int be = 1;//be=1表示不缩放
if (w > h && w > ww) {//如果宽度大的话根据宽度固定大小缩放
be = (int) (newOpts.outWidth / ww);
} else if (w < h && h > hh) {//如果高度高的话根据宽度固定大小缩放
be = (int) (newOpts.outHeight / hh);
}
if (be <= 0)
be = 1;
newOpts.inSampleSize = be;//设置缩放比例
//重新读入图片，注意此时已经把options.inJustDecodeBounds 设回false了
isBm = new ByteArrayInputStream(baos.toByteArray());
bitmap = BitmapFactory.decodeStream(isBm, null, newOpts);
return qualityCompressBitmap(bitmap);//压缩好比例大小后再进行质量压缩
// return bitmap;//压缩好比例大小
}
public static byte[] transferBitmapToBytes(Bitmap bitmap){
ByteArrayOutputStream output = new ByteArrayOutputStream();//初始化一个流对象
bitmap.compress(Bitmap.CompressFormat.PNG, 100, output);//把bitmap100%高质量压缩 到 output对象里
bitmap.recycle();//自由选择是否进行回收
byte[] result = output.toByteArray();//转换成功了
try {
output.close();
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
/**
* 设置照片
* @param imageView
* @param bytes
*/
public static void setBitmap(ImageView imageView, byte[] bytes){
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = false;
options.inSampleSize = 2;//图片宽高都为原来的二分之一，即图片为原来的四分之一
Bitmap bitmap = BitmapFactory.decodeByteArray(bytes,0,bytes.length, options);
imageView.setImageBitmap(bitmap);
if (bitmap != null&&!bitmap.isRecycled()){
bitmap.isRecycled();
bitmap = null;
System.gc();
}
}
public static Bitmap getBitmap(byte[] bytes){
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = false;
options.inSampleSize = 2;//图片宽高都为原来的二分之一，即图片为原来的四分之一
Bitmap bitmap = BitmapFactory.decodeByteArray(bytes,0,bytes.length, options);
return bitmap;
}
/**
* 将图片转成指定弧度（角度）的图片
*
* @param bitmap 需要修改的图片
* @param pixels 圆角的弧度
* @return 圆角图片
*/
public static Bitmap toRoundCorner(Bitmap bitmap, int pixels) {
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
//根据图片创建画布
Canvas canvas = new Canvas(output);
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
final float roundPx = pixels;
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(0xff424242);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}
public static Bitmap toRoundBitmap(Bitmap bitmap) {
int width = bitmap.getWidth();
int height = bitmap.getHeight();
float roundPx;
float left,top,right,bottom,dst_left,dst_top,dst_right,dst_bottom;
if (width <= height) {
roundPx = width / 2;
top = 0;
bottom = width;
left = 0;
right = width;
height = width;
dst_left = 0;
dst_top = 0;
dst_right = width;
dst_bottom = width;
} else {
roundPx = height / 2;
float clip = (width - height) / 2;
left = clip;
right = width - clip;
top = 0;
bottom = height;
width = height;
dst_left = 0;
dst_top = 0;
dst_right = height;
dst_bottom = height;
}
Bitmap output = Bitmap.createBitmap(width,
height, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect src = new Rect((int)left, (int)top, (int)right, (int)bottom);
final Rect dst = new Rect((int)dst_left, (int)dst_top, (int)dst_right, (int)dst_bottom);
final RectF rectF = new RectF(dst);
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(bitmap, src, dst, paint);
return output;
}
}
工具类的这些方法的都是项目上经常用的，后面发现更好的再补充上。
