Android笔记之——事件的发生（2）

Java：

package com.example.helloworld;

import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

/**
 * Created by admin on 2016/12/14.
 */

public class listener2Activity extends MainActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_listener2);

        Button button = (Button)findViewById(R.id.button);
        button.setOnKeyListener(new View.OnKeyListener() {
            @Override
            public boolean onKey(View view, int i, KeyEvent keyEvent) {
                Toast.makeText(listener2Activity.this,i,Toast.LENGTH_SHORT).show();
                return true;
            }
        });

        //焦点事件
//        button.setOnFocusChangeListener(new View.OnFocusChangeListener() {
//            @Override
//            public void onFocusChange(View view, boolean b) {
//                System.out.println("焦点...");
//            }
//        });
    }
}

XML：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    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"
    tools:context="com.example.helloworld.MainActivity">

        />

    <Button
        android:text="Button"
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="31dp"
        android:layout_below="@+id/button1"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginLeft="77dp"
        android:layout_marginStart="77dp" />

</RelativeLayout>