Android_01_按钮点击事件的四种写法

package com.example.day_02_click;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

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

Button btn1 = (Button) findViewById(R.id.btn1);
btn1.setOnClickListener(new MyClickListener());

}

class MyClickListener  implements OnClickListener{

@Override
public void onClick(View v) {
System.out.println("it's button1");

}

}

}

package com.example.day_02_click;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

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

Button btn2 = (Button) findViewById(R.id.btn2);
btn2.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
System.out.println("it's button2");

}
});

}

}

package com.example.day_02_click;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity implements OnClickListener{

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

Button btn3 = (Button) findViewById(R.id.btn3);
btn3.setOnClickListener(this);

}

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
System.out.println("it's button3");
}

}

package com.example.day_02_click;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

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

}

public void click(View v) {
System.out.println("it's button4");
}

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</strong>

<LinearLayout 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"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context=".MainActivity" >

<Button
android:id="@+id/btn1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="button1" />

<Button
android:id="@+id/btn2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="button2" />

<Button
android:id="@+id/btn3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="button3" />

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="button4"
android:onClick="click"
/>

</LinearLayout>