Android 微信分享图片（好友和朋友圈）

一. 配置

（1）module下build.gradle

implementation ('com.xyzlf.share:sharesdk:0.0.10') {
    exclude group: 'com.android.support', module: 'appcompat-v7'
}

（2）AndroidManifest.xml

权限：

与activity平级，设置微信key：

二. 实现

（1）注册wxapi, 

IWXAPI wxapi = WXAPIFactory.createWXAPI(this, "你的微信appid", true);
// 注册
wxapi.registerApp("你的微信appid");

（2）分享图片方法

private static final int THUMB_SIZE = 150;

/**
 * 分享图片
 * @param bitmap    图片
 * @param shareType    0：分享到好友  1：分享到朋友圈
 */
private void sharePicture(Bitmap bitmap, int shareType) {
    WXImageObject imgObj = new WXImageObject(bitmap);

    WXMediaMessage msg = new WXMediaMessage();
    msg.mediaObject = imgObj;

    Bitmap thumbBitmap = Bitmap.createScaledBitmap(bitmap, THUMB_SIZE, THUMB_SIZE, true);
    bitmap.recycle();
    msg.thumbData = Util.bmpToByteArray(thumbBitmap);  //设置缩略图

    SendMessageToWX.Req req = new SendMessageToWX.Req();
    req.transaction = buildTransaction("imgshareappdata");
    req.message = msg;
    req.scene = shareType;
    wxapi.sendReq(req);
}

public static byte[] bmpToByteArray(Bitmap bm) {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
    return baos.toByteArray();
}

private String buildTransaction(final String type) {
    return (type == null) ? String.valueOf(System.currentTimeMillis()) : type + System.currentTimeMillis();
}

（3）截屏方法（截取当前界面）

/**
 * 截屏
 *
 * @param activity  需要截屏的activity
 * @return
 */
public static Bitmap capture(Activity activity) {
    activity.getWindow().getDecorView().setDrawingCacheEnabled(true);
    Bitmap bmp = activity.getWindow().getDecorView().getDrawingCache();
    return bmp;
}

（4）调用

sharePicture(capture(MainActivity.this), 0);

至此，分享图片功能完成。

三. 扩展

下面是微信分享文字，链接，视频的

/*
 * 分享文字
 */
private void shareText(String text, int shareType) {
    //初始化一个WXTextObject对象
    WXTextObject textObj = new WXTextObject();
    textObj.text = text;
    //用WXTextObject对象初始化一个WXMediaMessage对象
    WXMediaMessage msg = new WXMediaMessage();
    msg.mediaObject = textObj;
    msg.description = text;
    //构造一个Req
    SendMessageToWX.Req req = new SendMessageToWX.Req();
    //transaction字段用于唯一标识一个请求
    req.transaction = buildTransaction("textshare");
    req.message = msg;
    //发送的目标场景， 可以选择发送到会话 WXSceneSession 或者朋友圈 WXSceneTimeline。 默认发送到会话。
    req.scene = shareType;
    mWXApi.sendReq(req);
}

/*
 * 分享链接
 */
private void shareWebPage(ShareContent shareContent, int shareType) {
    WXWebpageObject webpage = new WXWebpageObject();
    webpage.webpageUrl = shareContent.getURL();
    WXMediaMessage msg = new WXMediaMessage(webpage);
    msg.title = shareContent.getTitle();
    msg.description = shareContent.getContent();

    Bitmap thumb = BitmapFactory.decodeResource(mContext.getResources(), shareContent.getPictureResource());
    if(thumb == null) {
        Toast.makeText(mContext, "图片不能为空", Toast.LENGTH_SHORT).show();
    } else {
        msg.thumbData = Util.bmpToByteArray(thumb);
    }

    SendMessageToWX.Req req = new SendMessageToWX.Req();
    req.transaction = buildTransaction("webpage");
    req.message = msg;
    req.scene = shareType;
    mWXApi.sendReq(req);
}

/*
 * 分享视频
 */
private void shareVideo(ShareContent shareContent, int shareType) {
    WXVideoObject video = new WXVideoObject();
    video.videoUrl = shareContent.getURL();

    WXMediaMessage msg = new WXMediaMessage(video);
    msg.title = shareContent.getTitle();
    msg.description = shareContent.getContent();
    Bitmap thumb = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.ic_launcher_background);
    //    BitmapFactory.decodeStream(new URL(video.videoUrl).openStream());
    /**
     * 测试过程中会出现这种情况，会有个别手机会出现调不起微信客户端的情况。造成这种情况的原因是微信对缩略图的大小、title、description等参数的大小做了限制，所以有可能是大小超过了默认的范围。
     * 一般情况下缩略图超出比较常见。Title、description都是文本，一般不会超过。
     */
    Bitmap thumbBitmap =  Bitmap.createScaledBitmap(thumb, THUMB_SIZE, THUMB_SIZE, true);
    thumb.recycle();
    msg.thumbData = Util.bmpToByteArray(thumbBitmap);

    SendMessageToWX.Req req = new SendMessageToWX.Req();
    req.transaction = buildTransaction("video");
    req.message = msg;
    req.scene =  shareType;
    mWXApi.sendReq(req);
}