我知道,重复这个问题,但我无法找到在互联网上的答案。
我要打电话从其他类中的方法。
我有1类和类2。
在2级我有这个方法:
公共无效updateEmployee()方法{
//一些code
}
我要打电话从1级的方法。
感谢您的任何答复。
----编辑----
最后按钮为btnUpdate =(按钮)findViewById(R.id.btnUpd);
btnUpdate.setOnClickListener(新View.OnClickListener(){
公共无效的onClick(视图v){
员工updEmple =新员工();
updEmple.UpdateEmployee();
}
});
---- LogCat中---
05-28 16:30:44.030:E / AndroidRuntime(25198):致命异常:主要
05-28 16:30:44.030:E / AndroidRuntime(25198):显示java.lang.NullPointerException:需要的println消息
05-28 16:30:44.030:E / AndroidRuntime(25198):在android.util.Log.println_native(本机方法)
05-28 16:30:44.030:E / AndroidRuntime(25198):在android.util.Log.v(Log.java:116)
05-28 16:30:44.030:E / AndroidRuntime(25198):在and.net.Employee.UpdateEmployee(Employee.java:77)
05-28 16:30:44.030:E / AndroidRuntime(25198):在and.net.AndActivity $ 2.onClick(AndActivity.java:51)
05-28 16:30:44.030:E / AndroidRuntime(25198):在android.view.View.performClick(View.java:2485)
05-28 16:30:44.030:E / AndroidRuntime(25198):在android.view.View $ PerformClick.run(View.java:9080)
05-28 16:30:44.030:E / AndroidRuntime(25198):在android.os.Handler.handleCallback(Handler.java:587)
05-28 16:30:44.030:E / AndroidRuntime(25198):在android.os.Handler.dispatchMessage(Handler.java:92)
05-28 16:30:44.030:E / AndroidRuntime(25198):在android.os.Looper.loop(Looper.java:123)
05-28 16:30:44.030:E / AndroidRuntime(25198):在android.app.ActivityThread.main(ActivityThread.java:3683)
05-28 16:30:44.030:E / AndroidRuntime(25198):在java.lang.reflect.Method.invokeNative(本机方法)
05-28 16:30:44.030:E / AndroidRuntime(25198):在java.lang.reflect.Method.invoke(Method.java:507)
05-28 16:30:44.030:E / AndroidRuntime(25198):在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:839)
05-28 16:30:44.030:E / AndroidRuntime(25198):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
05-28 16:30:44.030:E / AndroidRuntime(25198):在dalvik.system.NativeStart.main(本机方法)
解决方案
您应使用以下code:
类2 CLS2 =新的Class2();
cls2.UpdateEmployee();
如果你不希望创建一个新的实例调用该方法,可以decalre的方法,静态
,然后你可以叫 Class2.UpdateEmployee();
I know that this Question is repeated but I can't find the answer in Internet.
I want to call a method from another class.
I've Class1 and Class2.
In Class 2 I've that method:
public void UpdateEmployee(){
//some code
}
I want to call that method from Class1.
Thanks for any answer.
----EDIT----
final Button btnUpdate = (Button)findViewById(R.id.btnUpd);
btnUpdate.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Employee updEmple = new Employee();
updEmple.UpdateEmployee();
}
});
----LogCat---
05-28 16:30:44.030: E/AndroidRuntime(25198): FATAL EXCEPTION: main
05-28 16:30:44.030: E/AndroidRuntime(25198): java.lang.NullPointerException: println needs a message
05-28 16:30:44.030: E/AndroidRuntime(25198): at android.util.Log.println_native(Native Method)
05-28 16:30:44.030: E/AndroidRuntime(25198): at android.util.Log.v(Log.java:116)
05-28 16:30:44.030: E/AndroidRuntime(25198): at and.net.Employee.UpdateEmployee(Employee.java:77)
05-28 16:30:44.030: E/AndroidRuntime(25198): at and.net.AndActivity$2.onClick(AndActivity.java:51)
05-28 16:30:44.030: E/AndroidRuntime(25198): at android.view.View.performClick(View.java:2485)
05-28 16:30:44.030: E/AndroidRuntime(25198): at android.view.View$PerformClick.run(View.java:9080)
05-28 16:30:44.030: E/AndroidRuntime(25198): at android.os.Handler.handleCallback(Handler.java:587)
05-28 16:30:44.030: E/AndroidRuntime(25198): at android.os.Handler.dispatchMessage(Handler.java:92)
05-28 16:30:44.030: E/AndroidRuntime(25198): at android.os.Looper.loop(Looper.java:123)
05-28 16:30:44.030: E/AndroidRuntime(25198): at android.app.ActivityThread.main(ActivityThread.java:3683)
05-28 16:30:44.030: E/AndroidRuntime(25198): at java.lang.reflect.Method.invokeNative(Native Method)
05-28 16:30:44.030: E/AndroidRuntime(25198): at java.lang.reflect.Method.invoke(Method.java:507)
05-28 16:30:44.030: E/AndroidRuntime(25198): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
05-28 16:30:44.030: E/AndroidRuntime(25198): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
05-28 16:30:44.030: E/AndroidRuntime(25198): at dalvik.system.NativeStart.main(Native Method)
解决方案
You should use the following code :
Class2 cls2= new Class2();
cls2.UpdateEmployee();
In case you don't want to create a new instance to call the method, you can decalre the method as static
and then you can just call Class2.UpdateEmployee();