Android的相关事件

Posted 2021-01-20 城南少年与猫

android的相关事件

1.Toast信息提醒

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class FirstActivity extends AppCompatActivity {
    private static final String TAG = "FirstActivity";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.first_layout);
// 获取按钮
        Button button1 = (Button) findViewById(R.id.button_1);
//点击事件
        button1.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
//  弹出信息
                Toast.makeText(FirstActivity.this,"You click button1",
                Toast.LENGTH_SHORT).show();
            }
        });
    }
}

2.在活动中使用Menu

res下新建一个Director,名为menu,在menu中建一个main的menuresourceFile(右键新建即可)

main.xml:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/add_item"
        android:title="Add" />
    <item
        android:id="@+id/remove_item"
        android:title="Remove" />
</menu>

FirstActivity.java

package com.example.activitytest;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class FirstActivity extends AppCompatActivity {

    private static final String TAG = "FirstActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.first_layout);
        //获取按钮
        Button button1 = (Button) findViewById(R.id.button_1);
        //点击事件
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //弹出信息
                Toast.makeText(FirstActivity.this, "You click button1",
                        Toast.LENGTH_SHORT).show();
            }
        });
    }

    //定义菜单的选项
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    //定义菜单选项的点击事件
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.add_item:
                Toast.makeText(this, "点击了add", Toast.LENGTH_LONG).show();
                break;
            case R.id.remove_item:
                Toast.makeText(this, "点击了remove", Toast.LENGTH_LONG).show();
                break;
            default:
        }
        return true;
    }
}

3.销毁一个活动

一般我们点击Back按钮可以实现返回的效果,如果需要自定义销毁可以调用finish()方法

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.first_layout);
        //获取按钮
        Button button1 = (Button) findViewById(R.id.button_1);
        //点击事件
        button1.setOnClickListener(new View.OnClickListener() {
            @Override   
            //销毁一个活动
            public void onClick(View v) {
                //销毁 和Back键的效果是一样的
                finish();
            }
        });
    }