build.gradle中添加微信依赖

  //微信
    api 'com.tencent.mm.opensdk:wechat-sdk-android-without-mta:+'

调用微信类

/**
 * Created by 14178 on 2018/1/19.
 */

public class WxLogin {

    public static IWXAPI api;
    public static Context mContext;

    /**
     * 初始化
     *
     * @param context
     */
    public static void initWx(Context context) {
        UIUtils.initContext(context);
        mContext = context;
        api = WXAPIFactory.createWXAPI(context, Constants.WX_APPID, true);
        api.registerApp(Constants.WX_APPID);

        final IWXAPI msgApi = WXAPIFactory.createWXAPI(context, null);
        // 将该app注册到微信
        msgApi.registerApp(Constants.WX_APPID);
    }



    /**
     * 微信支付
     */
    public static void payWx(BuyBean.DataBean.ParamsBean paramsBean) {
        long timecurrentTimeMillis = System.currentTimeMillis();
        long second = timecurrentTimeMillis / 1000;
        HashMap<String, String> map = new HashMap<>();
        String urlSign = RequestUtil.createUrlSign(map, true);
        Log.e("TAG", "payWx: sign" + urlSign);


        PayReq request = new PayReq();
        request.appId = paramsBean.getAppid();
        request.partnerId = paramsBean.getPartnerid();
        request.prepayId = paramsBean.getPrepayid();
        request.packageValue = "Sign=WXPay";                      //固定值
        request.nonceStr = paramsBean.getNoncestr();              //随机数
        request.timeStamp = paramsBean.getTimestamp();
        request.sign = paramsBean.getSign();
        api.sendReq(request);
    }
}

在Application中调用初始化微信

public class UserApplication extends Application {
    private IWXAPI api;
    private static UserApplication instance;
    public static Context mAppContext = null;
    public static UserApplication getInstance() {
        return instance;
    }
    @Override
    public void onCreate() {
        super.onCreate();
        instance = this;
        mAppContext = this;
        WxLogin.initWx(this);
    }

然后从后台请求到微信支付指定参数后，具体参数含义

1621584202(1).png

拿到参数后，去拉起微信

    public void toBuy(BuyBean buyBean) {
        Log.e(TAG, "toBuy: " + buyBean.toString());
        BuyBean.DataBean.ParamsBean params = buyBean.getData().getParams();
        WxLogin.payWx(params);
    }

微信支付的回调：
1.需要在项目中创建wxapi的包
在此包下创建WXPayEntryActivity文件

1621584433(1).png

2.继承Activity, 实现IWXAPIEventHandler接口后
会重写两个方法：onReq()和onResp()

3.重写onCreate方法

    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        api = WXAPIFactory.createWXAPI(this, Constants.WX_APPID);
        api.handleIntent(getIntent(), this);        //必须调用，否则wx不回调
    }

4.重写onNewIntent方法

    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        setIntent(intent);
        api.handleIntent(intent, this);             //必须调用，否则wx不回调
    }

5.onResp()方法

    public void onResp(BaseResp baseResp) {
        Log.d(TAG, "onPayFinish,errCode=" + baseResp.errCode);            
        finish();
    }

微信会在onResp()中回调支付结果 errorcode 返回码对应下图

1621584781(1).png