android事件

基于监听的事件处理机制

1.直接用匿名内部类

MainAcivity.java:

package com.jay.example.innerlisten;    
    
import android.os.Bundle;    
import android.view.View;    
import android.view.View.OnClickListener;    
import android.widget.Button;    
import android.widget.Toast;    
import android.app.Activity;    
    
    
public class MainActivity extends Activity {    
    private Button btnshow;    
        
    @Override    
    protected void onCreate(Bundle savedInstanceState) {    
        super.onCreate(savedInstanceState);    
        setContentView(R.layout.activity_main);    
        btnshow = (Button) findViewById(R.id.btnshow);    
        btnshow.setOnClickListener(new OnClickListener() {    
            //重写点击事件的处理方法onClick()    
            @Override    
            public void onClick(View v) {    
                //显示Toast信息    
                Toast.makeText(getApplicationContext(), "你点击了按钮", Toast.LENGTH_SHORT).show();    
            }    
        });    
    }        
} 

2.内部类,可复用

public class MainActivity extends Activity {    
    private Button btnshow;    
    @Override    
    protected void onCreate(Bundle savedInstanceState) {    
        super.onCreate(savedInstanceState);    
        setContentView(R.layout.activity_main);    
        btnshow = (Button) findViewById(R.id.btnshow);    
        //直接new一个内部类对象作为参数    
        btnshow.setOnClickListener(new BtnClickListener());    
    }     
    //定义一个内部类,实现View.OnClickListener接口,并重写onClick()方法    
    class BtnClickListener implements View.OnClickListener    
    {    
        @Override    
        public void onClick(View v) {    
            Toast.makeText(getApplicationContext(), "按钮被点击了", Toast.LENGTH_SHORT).show();   
        }    
    }    
} 

3直接使用Activity作为事件监听器

//让Activity方法实现OnClickListener接口    
public class MainActivity extends Activity implements OnClickListener{    
    private Button btnshow;    
    @Override    
    protected void onCreate(Bundle savedInstanceState) {    
        super.onCreate(savedInstanceState);    
        setContentView(R.layout.activity_main);    
            
        btnshow = (Button) findViewById(R.id.btnshow);    
        //直接写个this    
        btnshow.setOnClickListener(this);    
    }    
    //重写接口中的抽象方法    
    @Override    
    public void onClick(View v) {    
        Toast.makeText(getApplicationContext(), "点击了按钮", Toast.LENGTH_SHORT).show();         
    }         
}   

4 使用外部类：

MyClick.java

package com.jay.example.innerlisten;    
    
import android.view.View;    
import android.view.View.OnClickListener;    
import android.widget.TextView;    
    
public class MyClick implements OnClickListener {    
    private TextView textshow;    
    //把文本框作为参数传入    
    public MyClick(TextView txt)    
    {    
        textshow = txt;    
    }    
    @Override    
    public void onClick(View v) {    
        //点击后设置文本框显示的文字    
        textshow.setText("点击了按钮!");    
    }    
}

public class MainActivity extends Activity {    
    private Button btnshow;    
    private TextView txtshow;    
    @Override    
    protected void onCreate(Bundle savedInstanceState) {    
        super.onCreate(savedInstanceState);    
        setContentView(R.layout.activity_main);    
        btnshow = (Button) findViewById(R.id.btnshow);    
        txtshow = (TextView) findViewById(R.id.textshow);    
        //直接new一个外部类，并把TextView作为参数传入    
        btnshow.setOnClickListener(new MyClick(txtshow));    
    }         
} 

5.

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/button2"
        android:text="请求"
        android:onClick="QuestClick"
        />

    public void  QuestClick(View view){

    }

快速创建事件 alt+enter

结果：