Android Fabric - 空指针异常：弹出窗口布局中的按钮

Question

我正在使用Fabric插件。我只想在一个弹出窗口中嵌入一个Twitter登录按钮，该窗口的布局位于一个单独的XML布局文件中，其中包含登录按钮。

登录按钮在以下函数中定义，该函数在启动它的活动的onCreate()函数内调用，但logcat警告 loginButton <中的空指针异常/强>

确保XML中按钮的id没有问题。这有什么问题？

提前致谢！

private void TwitterLoginBtn() {

btn_twitter = (Button) findViewById(R.id.btn_twitter);

btn_twitter.setOnClickListener(new View.OnClickListener()
{
    @Override
    public void onClick(View v)
    {
        LayoutInflater layoutInflater
                = (LayoutInflater)getBaseContext()
                .getSystemService(LAYOUT_INFLATER_SERVICE);

        View popupView = layoutInflater.inflate(R.layout.twitter_login, null);
        TWin = new PopupWindow(
                popupView,
                LayoutParams.WRAP_CONTENT,
                LayoutParams.WRAP_CONTENT);

        //LinearLayout popLayout = (LinearLayout)getLayoutInflater().inflate(R.layout.twitter_login, null);

        //TWin = new PopupWindow(ShotActivity1.this);

        //TWin.setContentView(popLayout);

        loginButton = (TwitterLoginButton) findViewById(R.id.btn_twitter_login);

        loginButton.setCallback(new Callback<TwitterSession>() {
            @Override
            public void success(Result<TwitterSession> result) {
                // The TwitterSession is also available through:
                // Twitter.getInstance().core.getSessionManager().getActiveSession()
                TwitterSession session = result.data;
                // TODO: Remove toast and use the TwitterSession's userID
                // with your app's user model
                String msg = "@" + session.getUserName() + " logged in! (#" + session.getUserId() + ")";
                Toast.makeText(getApplicationContext(), msg, Toast.LENGTH_LONG).show();
            }
            @Override
            public void failure(TwitterException exception) {
                Log.d("TwitterKit", "Login with Twitter failure", exception);
            }
        });


        Button btn_closeTwitter = (Button)findViewById(R.id.btn_closeT);

        btn_closeTwitter.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View v)
            {
                TWin.dismiss();

            }
        });

        TWin.setBackgroundDrawable(null);
        TWin.showAsDropDown(v, 0, 0);


    }
});

Answer 1

您必须在用户点击TwitterLoginButton Callback<TwitterSession>

之前设置loginButton对象 之前

所以，拿这个：

loginButton = (TwitterLoginButton) findViewById(R.id.btn_twitter_login);

    loginButton.setCallback(new Callback<TwitterSession>() {
        @Override
        public void success(Result<TwitterSession> result) {
            // The TwitterSession is also available through:
            // Twitter.getInstance().core.getSessionManager().getActiveSession()
            TwitterSession session = result.data;
            // TODO: Remove toast and use the TwitterSession's userID
            // with your app's user model
            String msg = "@" + session.getUserName() + " logged in! (#" + session.getUserId() + ")";
            Toast.makeText(getApplicationContext(), msg, Toast.LENGTH_LONG).show();
        }
        @Override
        public void failure(TwitterException exception) {
            Log.d("TwitterKit", "Login with Twitter failure", exception);
        }
    });

并将其置于 onCreate（）方法上。我记得再次阅读Android Twitter login not working with Fabric SDK - Callback must not be null

希望有所帮助：）