Android中的委托（通用）点击监听器

Question

假设我有几个按钮，它们的点击由一个通用处理程序处理，有没有一种方法可以定义一次侦听器而不为每个按钮定义 onClick 属性？

<Button android:onClick="handler" />

也许是浏览器或某些拦截器中的父委托.....假设您有 50 个按钮，您在点击时明确声明每个按钮？？？

Answer 1

最好的方法：让你的活动实现View.OnClickListener，然后像这样编写你的onClick方法：

public void onClick(View v) {
    final int id = v.getId();
    switch (id) {
    case R.id.button1:
        // your code for button1 here
        break;
    case R.id.button2:
        // your code for button2 here
        break;
    // even more buttons here
    }
}

然后，在您的 XML 布局文件中，您可以直接使用属性android:onClick: 设置点击监听器

<Button
    android:id="@+id/button1"
    android:onClick="onClick"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Button 1" />

Answer 2

是的，它可以在活动级别以编程方式实现。所以不需要在 XML 中定义“onClick”属性。

您定义了一个 View.OnClickListener 类。例如

View.OnClickListener buttonListener = new View.OnClickListener() {
         public void onClick(View v) {
             // here you can define different code for different buttons
         };

然后您将此侦听器附加到一个位置上的所有按钮

final Button button = findViewById(R.id.button_id);
     button.setOnClickListener(buttonListener);

Answer 3

是的，您可以这样做。

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
List<Button> buttons;
ViewGroup parentView;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    buttons = new ArrayList<>();
    parentView = (ViewGroup) findViewById(R.id.cord);


    //Replace the above line with the container view i.e.
    //Replace  parentView = (ViewGroup) findViewById(R.id.cord);
    // With parentView = (ViewGroup) findViewById(R.id.<YOUR MAIN VIEW/PARENT CONTAINER>);
    //R.id.cord is R.id.<YOUR MAIN VIEW/PARENT CONTAINER> for me because my Relative Layout 
    // container's name is cord.


    for(int i=0; i < parentView.getChildCount(); i++) {

        childView = parentView.getChildAt(i);
        //The if may change there are other options try them too.
        if(childView.getClass().getName().substring(35).equals("Button")){


            buttons.add((Button)parentView.getChildAt(i));
        }
        /*
        //Else part optional 
        //Remove comment to use
        else
            Log.e("Not","A Button");*/
    }

    for (int i =0;i<buttons.size();i++){
        buttons.get(i).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //Do the work here
                Log.d("Button Clicked",Integer.toString(view.getId()));
            }
        });
    }





    }
}

这是一种解决问题的方法...

Answer 4

这是我最终得出的解决方案，它仅适用于 touchables，例如 TextView 不是可触摸的：

在java中：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final MainActivity activity = this;
    /* Any kind of ViewGroup that is 
       parent of the common listener views. In the example it is the rootView */
    View rootView = this.getWindow().getDecorView().getRootView();

    // Buttons are touchables
    ArrayList<View> touchables = rootView.getTouchables();

    // Define the common on click listener for the buttons
    View.OnClickListener listener = new View.OnClickListener() {
        public final void onClick(View view) {
            activity.onBtnClick( (Button) view );
        }
    };

    // Iterate trough touchables and if the View is a button assign the listener
    for (View v: touchables) {
        // TODO: omit button if that common listener isn't meant for it
        if(v instanceof Button) {
            v.setOnClickListener(listener);
        }
    }
}

// The listener callback
protected final void onBtnClick(Button btn) {
    String btnStringId = btn.getResources().getResourceEntryName(btn.getId());
}

在 Kotlin 中：

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    /* Any kind of ViewGroup that is 
       parent of the common listener views. In the example it is the rootView */
    val rootView = window.decorView.rootView
    val touchables = rootView.touchables
    val listener = View.OnClickListener {
        onBtnClick(it as Button)
    }
    touchables.forEach { if (it is Button) {
        it.setOnClickListener(listener)
    }}
}

protected fun onBtnClick(btn: Button) {
    var btnStringId = btn.getResources().getResourceEntryName(btn.id)
}