在android中定义按钮事件的最佳实践 [英] Best practice for defining button events in android

问题描述

我有一个用 XML 定义的 Layout，它由几个 Button 组成.

I have a Layout defined in XML which consists of several Buttons.

目前我在 OnCreate 方法中执行此操作以针对按钮定义事件处理程序:

Currently I am doing this in the OnCreate method to define the event handlers against the buttons:

public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    Button newPicButton = (Button)findViewById(R.id.new_button);
    newPicButton.setOnClickListener(btnListener);
    ..... similarly for other buttons too
    .....
}

在 Button 的 onClick 事件内部，我启动了一个相机 Intent 来获取图片，并在 onActivityResult 回调我再次设置事件处理程序以及设置 View 像这样:

Inside of the Button's onClick event, I launch a camera Intent to get a picture and inside the onActivityResult callback I am again setting the event handlers along with setting the View like this:

protected void onActivityResult(int requestCode, int resultCode, Intent data) 
{ 
    setContentView(R.layout.main);
    Button newPicButton = (Button)findViewById(R.id.new_button);
    newPicButton.setOnClickListener(btnListener);
    ...similarly for other buttons too
}

我是 android 的新手，这种每次重新定义事件的方法对我来说似乎很脏.我想知道在这样的场景中定义按钮事件处理程序的最佳实践是什么.

I am new to android and this approach of redefining an event every time seems quite dirty to me. I would like to know what is the best practice in terms of defining button event handlers in scenarios like this.

粘贴我的完整课程

public class CameraAppActivity extends Activity 
{
    /** Called when the activity is first created. */

    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button newPicButton = (Button)findViewById(R.id.new_button);
        newPicButton.setOnClickListener(btnListener);
    }

    //---create an anonymous class to act as a button click listener---
    private OnClickListener btnListener = new OnClickListener()
    {

        public void onClick(View v)
        {   
             //Intent newPicIntent = new Intent(v.getContext(), NewPictureActivity.class);
             //startActivityForResult(newPicIntent, 0);
            Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
            startActivityForResult(cameraIntent, 999);
        } 

    };  

    protected void onActivityResult(int requestCode, int resultCode, Intent data) 
    {  

        setContentView(R.layout.main);
        Button newPicButton = (Button)findViewById(R.id.new_button);
        newPicButton.setOnClickListener(btnListener);

       //if I comment last two lines nothing happens when I click on button

    }  

主要问题是

setContentView(R.layout.main);
Button newPicButton = (Button)findViewById(R.id.new_button);
newPicButton.setOnClickListener(btnListener);

在 onActivityResult 中重新注册事件......这是正确的方法吗?还是我做错了什么?因为如果我不重新注册事件，当我点击按钮时什么也不会发生.

Re-registering events inside onActivityResult.. is it right approach? Or am I doing something wrong? Because If I don't re-register event nothing happens when I click the button.

推荐答案

为什么不在 XML 布局中注册 onClick 事件，然后在代码中处理.这就是我要做的:

Why not registering onClick event in the XML layout and then handle it in the code. This is how I would do it:

<Button
android:id="@+id/my_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Click me"
android:onClick="onBtnClicked">
</Button>

现在创建一个处理点击的方法

and now create a method that would handle clicks

public void onBtnClicked(View v){
    if(v.getId() == R.id.my_btn){
        //handle the click here
    }
}

或者，您可以为代码中的每个项目单独设置 OnClickListener.然后使用 if/else 或 switch 语句来确定原点.

Alternatively, you can set the OnClickListener individually for each item in the code. Then use the if/else or switch statements to determine the origin.

通过这种方式，您可以使用一种方法来处理一种布局中的所有按钮.

This way you can have one method that handles all buttons from one layout.

更新:
虽然这是一种有效的方法，但我强烈推荐第二种选择.它更干净、更易于维护，尤其是在您使用片段时.

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