Android基础04

断断续续，没有办法，又重头学习下基础知识。

1. 很简单的一个功能，利用intent传递数据
2. 菜单功能
   布局代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.bbw.androidtrainingcourse01.MainActivity">

    <EditText
        android:id="@+id/edit_message"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:hint="@string/edit_message"/>
    <Button
        android:id="@+id/button_send"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/button_send"
        android:onClick="sendMessage"/>


</LinearLayout>

传输数据

package com.example.bbw.androidtrainingcourse01;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

    public final static String MESSAGE = "com.example.bbw,androidtrainingcourse01.MESSAGE";

    private EditText editText;

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

    public void sendMessage(View view){
        Intent intent = new Intent(this,DisplayMessage.class);
        editText = (EditText) findViewById(R.id.edit_message);
        String message = editText.getText().toString();
        intent.putExtra(MESSAGE,message);//以键值对的形式传输数据
        startActivity(intent);
    }
}

接收数据

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

        Intent intent = getIntent();
        String message = intent.getStringExtra(MESSAGE);
        displayMessage = (TextView) findViewById(R.id.display_Message);
        displayMessage.setText(message);
    }

菜单功能
onCreateOptionsmenu()创建Menu菜单的项目
onOptionsItemSelected()处理菜单被选择运行后的事件处理

<?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>

@Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main,menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()){
            case R.id.add_item:
                Toast.makeText(this,"you click add item",Toast.LENGTH_SHORT).show();
                break;
            case R.id.remove_item:
                Toast.makeText(this,"you click remove item",Toast.LENGTH_SHORT).show();
                break;
            default:
        }
        return true;
    }