Android-button event listening, android event listening

Android-button event listening, android event listening

Summary of the four event listening methods for the Button

First, define a Button space in activity_main.xml.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context=".MainActivity" >    <Button        android:id="@+id/button1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentLeft="true"        android:layout_alignParentTop="true"        android:text="Button" /></RelativeLayout>

Well, now let's look at the four ways to write click events:

1. The most common method is to use an anonymous internal class as the event listener class.

package com.basillee.blogdemo;import android.os.Bundle;import android.app.Activity;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.Toast;public class MainActivity extends Activity {    private Button btnButton;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        btnButton=(Button)findViewById(R.id.button1);        btnButton.setOnClickListener(new OnClickListener() {            public void onClick(View arg0) {                Toast.makeText(MainActivity.this, "button clicked", Toast.LENGTH_LONG).show();            }        });    }}

 

2. Internal class as listener

package com.basillee.blogdemo;import android.os.Bundle;import android.app.Activity;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.Toast;public class MainActivity extends Activity {private Button btnButton;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);btnButton=(Button)findViewById(R.id.button1);MyClicked myClicked=new MyClicked();btnButton.setOnClickListener(myClicked);}private class MyClicked implements OnClickListener{@Overridepublic void onClick(View arg0) {Toast.makeText(getApplicationContext(), "Button clicked!", Toast.LENGTH_LONG).show();}}}

3. The Activity directly implements the OnClickListener interface.

Package com. basillee. blogdemo;

Import android. OS. Bundle;
Import android. app. Activity;
Import android. view. View;
Import android. view. View. OnClickListener;
Import android. widget. Button;
Import android. widget. Toast;

Public class MainActivity extends Activity implements OnClickListener {

Private Button btnButton;
@ Override
Protected void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. activity_main );
BtnButton = (Button) findViewById (R. id. button1 );
BtnButton. setOnClickListener (this );
}
@ Override
Public void onClick (View arg0 ){
Toast. makeText (this, "Button clicked! ", Toast. LENGTH_LONG). show ();
}

}

4. In the layout file, use the android: onClick attribute to specify the corresponding method name.

The activity_main.xml code is as follows:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context=".MainActivity" >    <Button        android:id="@+id/button1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentLeft="true"        android:layout_alignParentTop="true"        android:text="Button"         android:onClick="myClick"/></RelativeLayout>

The MainActivity. java code is as follows:

package com.basillee.blogdemo;import android.os.Bundle;import android.app.Activity;import android.view.View;import android.widget.Toast;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}public void myClick(View v){Toast.makeText(getApplicationContext(),"Button clicked!", Toast.LENGTH_LONG).show();}}