安卓学习之初试事件响应——Button

迈不过友情╰ 2022-05-31 10:25 132阅读 0赞

1.界面布局

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        >
    <TextView  
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:text="@string/hello"
        />
       <Button 
       android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
         android:text="Click me!"
         android:id="@+id/btn1"
       />
    </LinearLayout>

2.事件响应代码（两种），第二种被我注释了

package cn.edu.bit.cs;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.Toast;
    
    public class UseButtonActivity extends Activity {
    	private Button btn1=null;
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            btn1=(Button)this.findViewById(R.id.btn1);
            //使用独立的事件响应对象
            btn1.setOnClickListener(new ButtonClick());
            
            //使用匿名内部类挂接事件响应代码
    		/*
    		 btn1.setOnClickListener(new View.OnClickListener() {
            	private int counter=0;
    			public void onClick(View v) {
    				Button clickedButton=(Button)v;
    				counter++;
    				//在手机上显示短暂的信息
    				Toast info=Toast.makeText(UseButtonActivity.this, "Button "+v.getId()+" has been clicked "+ counter + " times!", Toast.LENGTH_SHORT);
    				info.setDuration(1);
    				info.show();
    			}
    		});
    		 */
    
            
        }
    }
    class ButtonClick implements OnClickListener{
    
    	private int counter=0;
    	public void onClick(View v) {
    		counter++;
    		//在logCat中才能看到输出
    		System.out.println("I'm clicked "+ counter + " times!");
    	}
    	
    }