dependencies {
 compile 'com.tencent.mm.opensdk:wechat-sdk-android-with-mta:1.0.2'
}

dependencies {
 compile 'com.tencent.mm.opensdk:wechat-sdk-android-without-mta:1.0.2'
}

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.READ_PHONE_STATE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

public static String APP_ID="你的APPID";
public static IWXAPI api;
public void onCreate() {
  super.onCreate();
  api = WXAPIFactory.createWXAPI(this, APP_ID, true);
  api.registerApp(APP_ID); 
}

private void onClickWeChatLogin() {
  if (WxApplicaiton.api == null) {
   WxApplication.api = WXAPIFactory.createWXAPI(this, WxApplication.APP_ID, true);
  }
  if (!WxApplication.api.isWXAppInstalled()) {
   ToastUtils.toast("您手机尚未安装微信，请安装后再登录");
   return;
  }
  WxApplication.api.registerApp(WxApplication.APP_ID);
  SendAuth.Req req = new SendAuth.Req();
  req.scope = "snsapi_userinfo";
  req.state = "wechat_sdk_xb_live_state";//官方说明：用于保持请求和回调的状态，授权请求后原样带回给第三方。该参数可用于防止csrf攻击（跨站请求伪造攻击），建议第三方带上该参数，可设置为简单的随机数加session进行校验
  WxApplication.api.sendReq(req);
 }

<activity
   android:name=".wxapi.WXEntryActivity"
   android:exported="true" />

public class WXEntryActivity extends AppCompatActivity implements IWXAPIEventHandler {
 public static final String TAG = WXEntryActivity.class.getSimpleName();
 public static String code;
 public static BaseResp resp = null;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_wxentry);
  boolean handleIntent = XBLiveApplication.api.handleIntent(getIntent(), this);
　　　　　//下面代码是判断微信分享后返回WXEnteryActivity的，如果handleIntent==false,说明没有调用IWXAPIEventHandler，则需要在这里销毁这个透明的Activity;
  if(handleIntent==false){
   Log.d(TAG, "onCreate: "+handleIntent);
   finish();
  }
 }
 @Override
 protected void onNewIntent(Intent intent) {
  super.onNewIntent(intent);
  setIntent(intent);
  XBLiveApplication.api.handleIntent(intent, this);
 }
 @Override
 public void onReq(BaseReq baseReq) {
  Log.d(TAG, "onReq: ");
  finish();
 }
 @Override
 public void onResp(BaseResp baseResp) {
  if (baseResp != null) {
   resp = baseResp;
   code = ((SendAuth.Resp) baseResp).code; //即为所需的code
  }
  switch (baseResp.errCode) {
   case BaseResp.ErrCode.ERR_OK:
    Log.d(TAG, "onResp: 成功");
    finish();
    break;
   case BaseResp.ErrCode.ERR_USER_CANCEL:
    Log.d(TAG, "onResp: 用户取消");
    finish();
    break;
   case BaseResp.ErrCode.ERR_AUTH_DENIED:
    Log.d(TAG, "onResp: 发送请求被拒绝");
    finish();
    break;
  }
 }

@Override
 protected void onResume() {
  Log.d(TAG, "onResume: 1");
  super.onResume();
  //这里的判断是为了区分如果不是不是从WXEntryActivity页面销毁重启的，不走下面的代码
  if (WXEntryActivity.resp != null) {
   if (WXEntryActivity.resp.getType() == ConstantsAPI.COMMAND_SENDAUTH) {
    Thread thread = new Thread(downloadRun);
    thread.start();
    try {
     thread.join();
    } catch (InterruptedException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
   }
  }
 }
 public Runnable downloadRun = new Runnable() {
  @Override
  public void run() {
   WXGetAccessToken();
  }
 };
 //根据code获取access_token,这里用第三方volley框架进行post请求
 private void WXGetAccessToken() {
  String getAccessTokenUrl = AccessTokenUrl;
  StringRequest request = new StringRequest(Request.Method.GET, getAccessTokenUrl, new Response.Listener<String>() {
   @Override
   public void onResponse(String response) {
    Log.d(TAG, "onResponse: " + response);
    Gson gson = new Gson();
    WeChatLoginTokenModel tokenModel = gson.fromJson(response, WeChatLoginTokenModel.class);
    refresh_token = tokenModel.getRefresh_token();
    WXGetRefreshAccessToken();
   }
  }, new Response.ErrorListener() {
   @Override
   public void onErrorResponse(VolleyError error) {
   }
  });
  request.setTag("weChatGetToken");
  XBLiveApplication.getHttpRequestQueue().add(request);
 }
 //拿到access_token后再次发送请求进行刷新access_token,拿到access_refresh和openid
 private void WXGetRefreshAccessToken() {
  String getRefresh_tokenUrl =Refresh_tokenUrl ;
  StringRequest request = new StringRequest(Request.Method.GET, getRefresh_tokenUrl, new Response.Listener<String>() {
   @Override
   public void onResponse(String response) {
    Gson gson = new Gson();
    WeChatLoginTokenModel tokenModel = gson.fromJson(response, WeChatLoginTokenModel.class);
    String access_token = tokenModel.getAccess_token();
    String openid = tokenModel.getOpenid();
    WXGetUserInfo(access_token, openid);
   }
  }, new Response.ErrorListener() {
   @Override
   public void onErrorResponse(VolleyError error) {
   }
  });
  request.setTag("weChatGetRefreshToken");
  XBLiveApplication.getHttpRequestQueue().add(request);
 }
 //获取用户信息
 private void WXGetUserInfo(String access_token, String openid) {
  String getUserInfoUrl =UserInfoUr;
  StringRequest request = new StringRequest(Request.Method.GET, getUserInfoUrl, new Response.Listener<String>() {
   @Override
   public void onResponse(String response) {
    Log.d(TAG, "onResponse3: " + response);
    Gson gson = new Gson();
    WeChatUserInfoModel userInfoModel = gson.fromJson(response, WeChatUserInfoModel.class);
    String city = userInfoModel.getCity();
    String userName = userInfoModel.getNickname();
    String userIcon = userInfoModel.getHeadimgurl();
    int sex = userInfoModel.getSex();//1:男；0:女；2:未知
    String province = userInfoModel.getProvince();
    openId_WX = userInfoModel.getOpenid();
    ToastUtils.toast("登录成功");
   }
  }, new Response.ErrorListener() {
   @Override
   public void onErrorResponse(VolleyError error) {
   }
  });
　　　　//下面代码是volley框架注册，请忽视
  request.setTag("weChatGetUserInfo");
  XBLiveApplication.getHttpRequestQueue().add(request);
 }