Android空指针异常怎么解决啊看不出哪里出错啊

Question

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at com.example.myappl.MainActivity.onCreate(MainActivity.java:19)
at android.app.Activity.performCreate(Activity.java:8290)
at android.app.Activity.performCreate(Activity.java:8269)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1384)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3657)

Answer 1

看一下你的布局里面有没有btn1这个控件如果不是这个原因的话，看一下sure这个里面的控件是不是有问题