private IWXAPI wxApi;  
//实例化  
wxApi = WXAPIFactory.createWXAPI(this, Constants.WX_APP_ID);  
wxApi.registerApp(Constants.WX_APP_ID);  
/** 
 * 微信分享 （这里仅提供一个分享网页的示例，其它请参看官网示例代码） 
 * @param flag(0:分享到微信好友，1：分享到微信朋友圈) 
 */  
private void wechatShare(int flag){  
    WXWebpageObject webpage = new WXWebpageObject();  
    webpage.webpageUrl = "这里填写链接url";  
    WXMediaMessage msg = new WXMediaMessage(webpage);  
    msg.title = "这里填写标题";  
    msg.description = "这里填写内容";  
    //这里替换一张自己工程里的图片资源  
    Bitmap thumb = BitmapFactory.decodeResource(getResources(), R.drawable.share_logo);  
    msg.setThumbImage(thumb);  
      
    SendMessageToWX.Req req = new SendMessageToWX.Req();  
    req.transaction = String.valueOf(System.currentTimeMillis());  
    req.message = msg;  
    req.scene = flag==0?SendMessageToWX.Req.WXSceneSession:SendMessageToWX.Req.WXSceneTimeline;  
    wxApi.sendReq(req);  
}  
//在需要分享的地方添加代码：  
wechatShare(0);//分享到微信好友  
wechatShare(1);//分享到微信朋友圈 

/** 微信客户端回调activity示例 */  
public class WXEntryActivity extends Activity implements IWXAPIEventHandler {  
    // IWXAPI 是第三方app和微信通信的openapi接口  
    private IWXAPI api;  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        api = WXAPIFactory.createWXAPI(this, "这里替换第一步申请的APP_ID", false);  
        api.handleIntent(getIntent(), this);  
        super.onCreate(savedInstanceState);  
    }  
    @Override  
    public void onReq(BaseReq arg0) { }  
  
    @Override  
    public void onResp(BaseResp resp) {  
        LogManager.show(TAG, "resp.errCode:" + resp.errCode + ",resp.errStr:"  
                + resp.errStr, 1);  
        switch (resp.errCode) {  
        case BaseResp.ErrCode.ERR_OK:  
            //分享成功  
            break;  
        case BaseResp.ErrCode.ERR_USER_CANCEL:  
            //分享取消  
            break;  
        case BaseResp.ErrCode.ERR_AUTH_DENIED:  
            //分享拒绝  
            break;  
        }  
    }  
}  

<activity    
    android:name=".wxapi.WXEntryActivity"  
    android:exported="true"  
    android:screenOrientation="portrait"   
    android:theme="@android:style/Theme.Translucent.NoTitleBar" />