ButterKnife与Handle使用控件报空指针问题

来源：互联网发布：面试问题知乎编辑：程序博客网时间：2024/05/17 22:24

Handler handler = new Handler() {    @Override    public void handleMessage(Message msg) {        super.handleMessage(msg);        what = msg.what;        if (what > 0) {            what--;            tv_yanzhengma_chongfa.setText(what + "s后重试");            handler.sendEmptyMessageDelayed(what, 1000);        } else {            tv_yanzhengma_chongfa.setText("重发校验码");            tv_yanzhengma_chongfa.setClickable(true);            tv_yanzhengma_chongfa.setTextColor(getResources().getColor(R.color.colorMainBlue));        }    }};

1. 短信验证码handle发送60s消息，页面返回时找不到handle里面的控件，报空指针异常。。。这时要在onCreateView()方法里面用findViewByid()注册控件，不能用ButterKnife注册控件。

异常信息：

1 Caused by: java.lang.NullPointerException
2 at com.example.yumin.fragment.MyQianbaoBindCardYZPhoneFragment$4.handleMessage(MyQianbaoBindCardYZPhoneFragment.java:167)
3 at android.os.Handler.dispatchMessage(Handler.java:102)
4 at android.os.Looper.loop(Looper.java:157)
5 at android.app.ActivityThread.main(ActivityThread.java:5293)
6 at java.lang.reflect.Method.invokeNative(Native Method)
7 at java.lang.reflect.Method.invoke(Method.java:515)
8 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
9 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
10 at dalvik.system.NativeStart.main(Native Method)

2.当前页面退出时，handle还在发送消息，else里面的控件也报空指针。。。这时要在onDestory()方法里面清除消息

  handler.removeMessages(what);

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