首先我们在activity_main.xml里面先定义一个Button空间
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<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 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> |
好，现在要我们来看点击事件的四种写法：
1.最常见的一种写法——匿名的内部类做为事件监听器类
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.内部类做为监听器
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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); MyClicked myClicked=new MyClicked(); btnButton.setOnClickListener(myClicked); } private class MyClicked implements OnClickListener{ @Override public void onClick(View arg0) { Toast.makeText(getApplicationContext(), "Button clicked!", Toast.LENGTH_LONG).show(); } }} |
3.Activity直接实现OnClickListener接口
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.在布局文件中，用android：onClick属性指定对应的方法名实现
activity_main.xml代码如下：
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<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 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> |
MainActivity.java代码如下：
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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 { @Override protected 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(); }} |