小编roh*_*de7的帖子

可能重复:
OnClick()事件和OnClickListener之间的区别？

我是Android开发的半新手,当我第一次开始时,我试图避免以任何必要的方式使用xml布局,因此我之前的一些项目涉及显式创建OnClickListener并将其实现为匿名内部类的按钮.如 -

final Button button = new Button(this);
button.setText("Click to change second line of text");

OnClickListener buttonListener = new View.OnClickListener() {
    boolean clicked = false;
    int numClicks = 0;

    @Override
    public void onClick(View v) {
        if(numClicks > 5) {
            button.setText("STOP IT");
        }
        numClicks++;
        if(clicked == false){
            clicked = true;
            tv2.setText("Text Changed on Button Click");    
        }
        else
        {
            clicked = false;
            tv2.setText("Click again");
        }       
    }
};
button.setOnClickListener(buttonListener);

但随着我越来越熟悉android,我开始理解xml布局的价值,并实现了这样的按钮

    <Button
    android:id="@+id/button1"
    android:layout_height = "wrap_content"
    android:layout_width ="wrap_content"
    android:text = "lets do …

我正在尝试为Android创建一个应用程序,我按照本教程http://developer.android.com/training/basics/firstapp/starting-activity.html

有一部分

/** Called when the user clicks the Send button */
public void sendMessage(View view) {
    // Do something in response to button
}

然后我按照本教程,一切正常,直到我删除参数 View view

我的问题就是为什么每次我删除它,所以函数只是:

/** Called when the user clicks the Send button */
public void sendMessage() {
    // Do something in response to button
}

我运行应用程序,它被迫关闭.

谁能开导我？谢谢

While implementing the code from Google CodeLabs I am getting this crash report while starting the CameraActivity - CameraX - Google Code Labs

Logs: Process: in.novopay.novoloan, PID: 5845 java.lang.IllegalArgumentException: Unable to get camera ID for use case androidx.camera.core.Preview-4817149b-004d-42b8-a103-ea998038268b at androidx.camera.camera2.impl.Camera2DeviceSurfaceManager.getCameraIdFromConfig(Camera2DeviceSurfaceManager.java:310) at androidx.camera.camera2.impl.Camera2DeviceSurfaceManager.requiresCorrectedAspectRatio(Camera2DeviceSurfaceManager.java:268) at androidx.camera.core.Preview.updateUseCaseConfig(Preview.java:387) at androidx.camera.core.UseCase.(UseCase.java:92) at androidx.camera.core.Preview.(Preview.java:99) at in.novopay.uicontrollibrary.activities.CameraActivity.startCamera(CameraActivity.kt:94) at in.novopay.uicontrollibrary.activities.CameraActivity.access$startCamera(CameraActivity.kt:30) at in.novopay.uicontrollibrary.activities.CameraActivity$checkPermission$1.run(CameraActivity.kt:45) at android.os.Handler.handleCallback(Handler.java:790) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:164) at android.app.ActivityThread.main(ActivityThread.java:7000) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:441) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1408) Caused by: java.lang.IllegalArgumentException: Option does not exist: Option{id=camerax.core.camera.lensFacing, valueClass=class androidx.camera.core.CameraX$LensFacing, token=null} …

使用 构建 main.go 文件后go build go.main，我得到了主要的可执行文件。我如何运行主文件？如果我这样做go run main.go，它会自动构建 + 运行可执行文件。但我想知道运行已经构建的可执行文件的命令。