java NullPointerException Android处理程序
我试图强制方向为纵向运行此代码,但再次失败 每当我尝试处理程序在每秒钟后基本上更改视图文本时,我都会出现此错误 作为一名大学生,我是新来安卓开发的,所以如果我有错误,请容忍 先谢谢你 日志如下java NullPointerException Android处理程序,java,android,nullpointerexception,android-handler,Java,Android,Nullpointerexception,Android Handler,我试图强制方向为纵向运行此代码,但再次失败 每当我尝试处理程序在每秒钟后基本上更改视图文本时,我都会出现此错误 作为一名大学生,我是新来安卓开发的,所以如果我有错误,请容忍 先谢谢你 日志如下 public class MainActivity extends ActionBarActivity { Handler myHandler; Runnable myRunnable; TextView tv; int no; @Override
public class MainActivity extends ActionBarActivity {
Handler myHandler;
Runnable myRunnable;
TextView tv;
int no;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myHandler.post(myRunnable);
}
public void initialize(){
no = 10;
tv = (TextView) findViewById(R.id.textView1);
myRunnable = new Runnable() {
@Override
public void run() {
tv.setText(Integer.toString(no));
no--;
if(no != 0)
myHandler.postDelayed(myRunnable, 1000);
}
};
}
}
myHandler未初始化,并且由于onCreate()中未调用initialize()方法,因此在尝试发布myRunnable之前也未初始化它。myHandler未初始化,并且由于onCreate()中未调用initialize()方法,myRunnable在您尝试发布之前也不会初始化。myHandler没有初始化,并且由于onCreate()中没有调用initialize()方法,因此myRunnable在您尝试发布之前也不会初始化。myHandler没有初始化,并且由于initialize()方法方法没有在onCreate()中调用,在您尝试发布它之前,myRunnable也没有初始化。初始化
myHandler
as
10-04 04:22:35.750: E/AndroidRuntime(2123):FATAL EXCEPTION: main
10-04 04:22:35.750: E/AndroidRuntime(2123):java.lang.RuntimeException: Unable to start activity ComponentInfo{we.funnycorps.handlerpractise/we.funnycorps.handlerpractise.MainActivity}: java.lang.NullPointerException
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
Handler myHandler = new Handler();
i、 e.更换
Handler myHandler = new Handler();
到
在myHandler.post(myRunnable)之前调用initialize()
方法代码>作为
10-04 04:22:35.750: E/AndroidRuntime(2123):FATAL EXCEPTION: main
10-04 04:22:35.750: E/AndroidRuntime(2123):java.lang.RuntimeException: Unable to start activity ComponentInfo{we.funnycorps.handlerpractise/we.funnycorps.handlerpractise.MainActivity}: java.lang.NullPointerException
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
Handler myHandler = new Handler();
将myHandler初始化为
10-04 04:22:35.750: E/AndroidRuntime(2123):FATAL EXCEPTION: main
10-04 04:22:35.750: E/AndroidRuntime(2123):java.lang.RuntimeException: Unable to start activity ComponentInfo{we.funnycorps.handlerpractise/we.funnycorps.handlerpractise.MainActivity}: java.lang.NullPointerException
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
Handler myHandler = new Handler();
i、 e.更换
Handler myHandler = new Handler();
到
在myHandler.post(myRunnable)之前调用initialize()
方法代码>作为
10-04 04:22:35.750: E/AndroidRuntime(2123):FATAL EXCEPTION: main
10-04 04:22:35.750: E/AndroidRuntime(2123):java.lang.RuntimeException: Unable to start activity ComponentInfo{we.funnycorps.handlerpractise/we.funnycorps.handlerpractise.MainActivity}: java.lang.NullPointerException
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
Handler myHandler = new Handler();
将myHandler初始化为
10-04 04:22:35.750: E/AndroidRuntime(2123):FATAL EXCEPTION: main
10-04 04:22:35.750: E/AndroidRuntime(2123):java.lang.RuntimeException: Unable to start activity ComponentInfo{we.funnycorps.handlerpractise/we.funnycorps.handlerpractise.MainActivity}: java.lang.NullPointerException
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
Handler myHandler = new Handler();
i、 e.更换
Handler myHandler = new Handler();
到
在myHandler.post(myRunnable)之前调用initialize()
方法代码>作为
10-04 04:22:35.750: E/AndroidRuntime(2123):FATAL EXCEPTION: main
10-04 04:22:35.750: E/AndroidRuntime(2123):java.lang.RuntimeException: Unable to start activity ComponentInfo{we.funnycorps.handlerpractise/we.funnycorps.handlerpractise.MainActivity}: java.lang.NullPointerException
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
Handler myHandler = new Handler();
将myHandler初始化为
10-04 04:22:35.750: E/AndroidRuntime(2123):FATAL EXCEPTION: main
10-04 04:22:35.750: E/AndroidRuntime(2123):java.lang.RuntimeException: Unable to start activity ComponentInfo{we.funnycorps.handlerpractise/we.funnycorps.handlerpractise.MainActivity}: java.lang.NullPointerException
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
Handler myHandler = new Handler();
i、 e.更换
Handler myHandler = new Handler();
到
在myHandler.post(myRunnable)之前调用initialize()
方法代码>作为
10-04 04:22:35.750: E/AndroidRuntime(2123):FATAL EXCEPTION: main
10-04 04:22:35.750: E/AndroidRuntime(2123):java.lang.RuntimeException: Unable to start activity ComponentInfo{we.funnycorps.handlerpractise/we.funnycorps.handlerpractise.MainActivity}: java.lang.NullPointerException
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
10-04 04:22:35.750: E/AndroidRuntime(2123):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
Handler myHandler = new Handler();
您没有在oncreate中使用initialize()
函数,在代码使用下面,您将得到预期的结果
initialize();
myHandler.post(myRunnable);
您没有在oncreate中使用initialize()
函数,在代码使用下面,您将得到预期的结果
initialize();
myHandler.post(myRunnable);
您没有在oncreate中使用initialize()
函数,在代码使用下面,您将得到预期的结果
initialize();
myHandler.post(myRunnable);
您没有在oncreate中使用initialize()
函数,在代码使用下面,您将得到预期的结果
initialize();
myHandler.post(myRunnable);
你在哪里调用了initialize
方法。你应该在onCreateyou中调用它,因为你没有初始化myHandler,也没有在任何地方调用initialize()方法,所以在调用myHandler.post(myRunnable)时两者都为NULL;你在哪里调用了initialize
方法。你应该在onCreateyou中调用它,因为你没有初始化myHandler,也没有在任何地方调用initialize()方法,所以在调用myHandler.post(myRunnable)时两者都为NULL;你在哪里调用了initialize
方法。你应该在onCreateyou中调用它,因为你没有初始化myHandler,也没有在任何地方调用initialize()方法,所以在调用myHandler.post(myRunnable)时两者都为NULL;你在哪里调用了initialize
方法。你应该在onCreateyou中调用它,因为你没有初始化myHandler,也没有在任何地方调用initialize()方法,所以在调用myHandler.post(myRunnable)时两者都为NULL;