Question

我需要将侦听器设置为另一个xml中定义的按钮。我怎么做？我试过这个，但它给了我RunTimeException。

super.onCreate(savedInstanceState);
setContentView(R.layout.leavestatus_info_activity);
cancel_leave_button = (Button)findViewById(R.layout.leave_status_reason).findViewById(R.id.cancel_leave);

这是我的logcat：

03-12 11:36:19.125: E/AndroidRuntime(689): FATAL EXCEPTION: main
03-12 11:36:19.125: E/AndroidRuntime(689): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.empover.hrms.activity/com.empover.hrms.activity.LeaveStatusInfoActivity}: java.lang.NullPointerException
03-12 11:36:19.125: E/AndroidRuntime(689):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
03-12 11:36:19.125: E/AndroidRuntime(689):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
03-12 11:36:19.125: E/AndroidRuntime(689):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
03-12 11:36:19.125: E/AndroidRuntime(689):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
03-12 11:36:19.125: E/AndroidRuntime(689):  at android.os.Handler.dispatchMessage(Handler.java:99)
03-12 11:36:19.125: E/AndroidRuntime(689):  at android.os.Looper.loop(Looper.java:123)
03-12 11:36:19.125: E/AndroidRuntime(689):  at android.app.ActivityThread.main(ActivityThread.java:4627)
03-12 11:36:19.125: E/AndroidRuntime(689):  at java.lang.reflect.Method.invokeNative(Native Method)
03-12 11:36:19.125: E/AndroidRuntime(689):  at java.lang.reflect.Method.invoke(Method.java:521)
03-12 11:36:19.125: E/AndroidRuntime(689):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
03-12 11:36:19.125: E/AndroidRuntime(689):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
03-12 11:36:19.125: E/AndroidRuntime(689):  at dalvik.system.NativeStart.main(Native Method)
03-12 11:36:19.125: E/AndroidRuntime(689): Caused by: java.lang.NullPointerException
03-12 11:36:19.125: E/AndroidRuntime(689):  at com.empover.hrms.activity.LeaveStatusInfoActivity.onCreate(LeaveStatusInfoActivity.java:61)
03-12 11:36:19.125: E/AndroidRuntime(689):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
03-12 11:36:19.125: E/AndroidRuntime(689):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
03-12 11:36:19.125: E/AndroidRuntime(689):  ... 11 more

Answer 1

看看是否有效：

    setContentView(R.layout.first_layout);
    View v = LayoutInflater.from(this).inflate(R.layout.second_layout, null);

    Button b = (Button) v.findViewById(R.id.my_button);
    b.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

        }
    });

我在这里做的是在设置onclick监听器之前给第二个布局充气。在您的代码中，通过执行findViewById(R.layout.leave_status_reason).findViewById(R.id.cancel_leave);，您正在进行的是您在原始布局中查找名为leave_status_reason的布局，该布局并不存在。

修改好吧，它可能已经很晚了，你现在可能已经开始了，但是我想为后代纠正这个问题：为了让它发挥作用，你需要用你的父母替换null布局容器并使用View inflater。所以这一行将是：

LinearLayout container = (LinearLayout) findViewById(R.id.first_layout); View view = View.inflate(this, R.layout.my_layout, container);

然后它应该工作。

Answer 2

首先按LayoutInflater.inflate()对其他布局进行充气，然后在InflatedLayout

中找到该视图

cancel_leave_button = (Button)InflatedLayout.findViewById(R.id.cancel_leave);

如何访问另一个xml中定义的元素？

2 个答案: