有时分享出去的图片如果过长，就会导致缩略图的正方形图片呈现的效果是被压缩的，一般才用居中裁剪的方式，将裁剪后的图作为缩略图即可
本文后面将举微信分享到朋友圈和好友到例子，在分享出去到图片中，若为长图，则截取中间部分作为缩略图标，先放实现的代码。例子作为代码的复习笔记使用
实现图片居中裁剪代码如下：
//其中bitmap为老的Bitmap对象，将会被裁剪
Bitmap withSizeBitmap = null;//该withSizeBitmap是取过长宽的
Bitmap thumbBmp = null;//将上面的withSizeBitmap再次压缩否分享出去
if (bitmap.getWidth() < bitmap.getHeight()) {//如果是竖长图或正方形
//居中裁剪创建一个带有宽高的bitmap
withSizeBitmap = Bitmap.createBitmap(bitmap, 0, ((bitmap.getHeight() - bitmap.getWidth()) / 2), bitmap.getWidth(), bitmap.getWidth());
//压缩
thumbBmp = Bitmap.createScaledBitmap(withSizeBitmap, WX_THUMB_SIZE, WX_THUMB_SIZE, true);
}else if (bitmap.getWidth() >= bitmap.getHeight()){//如果是横长图
withSizeBitmap = Bitmap.createBitmap(bitmap, ((bitmap.getWidth() - bitmap.getHeight()) / 2), 0, bitmap.getHeight(), bitmap.getHeight());
thumbBmp = Bitmap.createScaledBitmap(withSizeBitmap, WX_THUMB_SIZE, WX_THUMB_SIZE, true);
}
分享朋友圈的方法：
/**
* 分享朋友圈
* @param url 链接
* @param title 标题
* @param content 内容简介
* @param imgPath 缩略图图片地址（本地）
* @param titleOrContent 分享出去的文字是标题还是简介
*/
public static void shareMoments(final String url, final String title, final String
content, final String imgPath, final boolean titleOrContent) {
final int IMAGE_SIZE = 32768;
new Thread(new Runnable() {
@Override
public void run() {
WXWebpageObject textObj = new WXWebpageObject();
textObj.webpageUrl = url;
WXMediaMessage msg = new WXMediaMessage();
if (titleOrContent){//标题还是描述都传过来，但是需要哪个根据此字段决定，
msg.title = title;
}else {
msg.title = content;
}
final int WX_THUMB_SIZE = 120;
try {
Bitmap bitmap = BitmapFactory.decodeFile(imgPath);
ByteArrayOutputStream output = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, output);
int options = 100;
while (output.toByteArray().length > IMAGE_SIZE && options != 10) {
output.reset(); //清空baos
bitmap.compress(Bitmap.CompressFormat.JPEG, options, output);//这里压缩options%，把压缩后的数据存放到baos中
options -= 10;
}
//这就是上面的裁剪的方法
Bitmap withSizeBitmap = null;
Bitmap thumbBmp = null;
if (bitmap.getWidth() < bitmap.getHeight()) {
withSizeBitmap = Bitmap.createBitmap(bitmap, 0, ((bitmap.getHeight() - bitmap.getWidth()) / 2), bitmap.getWidth(), bitmap.getWidth());
thumbBmp = Bitmap.createScaledBitmap(withSizeBitmap, WX_THUMB_SIZE, WX_THUMB_SIZE, true);
}else if (bitmap.getWidth() >= bitmap.getHeight()){
//创建一个带有宽高的bitmap
withSizeBitmap = Bitmap.createBitmap(bitmap, ((bitmap.getWidth() - bitmap.getHeight()) / 2), 0, bitmap.getHeight(), bitmap.getHeight());
//压缩
thumbBmp = Bitmap.createScaledBitmap(withSizeBitmap, WX_THUMB_SIZE, WX_THUMB_SIZE, true);
}
msg.thumbData = WXUtil.bmpToByteArray(thumbBmp, true);
bitmap.recycle();
withSizeBitmap.recycle();
thumbBmp.recycle();
msg.mediaObject = textObj;
SendMessageToWX.Req req = new SendMessageToWX.Req()
// req.transaction = content;
req.message = msg;
req.scene = SendMessageToWX.Req.WXSceneTimeline;
api.sendReq(req);
} catch (Exception e) {
e.printStackTrace();
}
}
}).start();
}
分享到微信好友到方法：
/**
* 分享微信好友
* @param url 网址
* @param title 标题
* @param content 简介
* @param imgPath 图片地址(本地)
*/
public static void shareWX(final String url, final String title, final String
content, final String imgPath) {
final int IMAGE_SIZE = 32768;
new Thread(new Runnable() {
@Override
public void run() {
final WXWebpageObject textObj = new WXWebpageObject();
textObj.webpageUrl = url;
final WXMediaMessage msg = new WXMediaMessage();
msg.title = title;//标题
msg.description = content;//描述
final int WX_THUMB_SIZE = 120;
//开始把图片路径转成bitmap
try {
Bitmap bitmap = BitmapFactory.decodeFile(imgPath);
ByteArrayOutputStream output = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, output);
int options = 100;
while (output.toByteArray().length > IMAGE_SIZE && options != 10) {//后面（options != 10）的条件判断必须加（vivo x7不加不行）
output.reset(); //清空baos
bitmap.compress(Bitmap.CompressFormat.JPEG, options, output);//这里压缩options%，把压缩后的数据存放到baos中
options -= 10;
}
Bitmap withSizeBitmap = null;
Bitmap thumbBmp = null;
if (bitmap.getWidth() < bitmap.getHeight()) {//竖图
withSizeBitmap = Bitmap.createBitmap(bitmap, 0, ((bitmap.getHeight() - bitmap.getWidth()) / 2), bitmap.getWidth(), bitmap.getWidth());
thumbBmp = Bitmap.createScale dBitmap(withSizeBitmap, WX_THUMB_SIZE, WX_THUMB_SIZE, true);
}else if (bitmap.getWidth() >= bitmap.getHeight()){//横图
withSizeBitmap = Bitmap.createBitmap(bitmap, ((bitmap.getWidth() - bitmap.getHeight()) / 2), 0, bitmap.getHeight(), bitmap.getHeight());
thumbBmp = Bitmap.createScaledBitmap(withSizeBitmap, WX_THUMB_SIZE, WX_THUMB_SIZE, true);
}
msg.thumbData = WXUtil.bmpToByteArray(thumbBmp, true);
//回收
bitmap.recycle();
withSizeBitmap.recycle();
thumbBmp.recycle();
//bitmap到此结束
msg.mediaObject = textObj;
SendMessageToWX.Req req = new SendMessageToWX.Req();
req.transaction = title;
req.message = msg;
req.scene = SendMessageToWX.Req.WXSceneSession;
api.sendReq(req);
} catch (Exception e) {
e.printStackTrace();
}
}
}).start();
}
结束。
