玩转Android---UI篇---EditText(编辑框)

java.lang.Object
↳	android.view.View
	↳	android.widget.TextView
		↳	android.widget.EditText

EditText是可编辑的文本框。

在用户没有输入的时候，我们默认在编辑框中显示“请输入数字”的提示，要实现这一功能很简单，秩序哟啊“EditText.setHint("请输入数字")”或者在XML布局文件上写上“android:hint="请输入数字"”即可

下面通过一个简单的计算器来说明EditText的使用

calculater.java源文件

package org.loulijun.calculate;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.Toast;

public class Calculater extends Activity {

/** Called when the activity is first created. */

private EditText numberone;

private EditText numbertwo;

private Button mybutton;

private TextView symbol;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

numberone=(EditText)findViewById(R.id.numberone);

numbertwo=(EditText)findViewById(R.id.numbertwo);

mybutton=(Button)findViewById(R.id.mybutton);

symbol=(TextView)findViewById(R.id.symbol);

mybutton.setOnClickListener(new Calculate());

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// TODO Auto-generated method stub

menu.add(0, 1, 1, R.string.exit);

menu.add(0,2,2,R.string.about);

return super.onCreateOptionsMenu(menu);

}

@Override

public boolean onOptionsItemSelected(MenuItem item) {

// TODO Auto-generated method stub

if(item.getItemId()==1)

{

finish();

}

else if(item.getItemId()==2)

{

Toast.makeText(this, "亲爱的你可知，我有多么思念你！", Toast.LENGTH_SHORT).show();

}

return super.onOptionsItemSelected(item);

}

class Calculate implements OnClickListener

{

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

String number1=numberone.getText().toString();

String number2=numbertwo.getText().toString();

Intent intent=new Intent();

intent.putExtra("num1",number1);

intent.putExtra("num2", number2);

intent.setClass(Calculater.this,Result.class);

Calculater.this.startActivity(intent);

}

Result.java源文件

package org.loulijun.calculate;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.widget.TextView;

public class Result extends Activity {

private TextView textview;

public void onCreate(Bundle savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.result);

textview=(TextView)findViewById(R.id.textview);

Intent intent=getIntent();

String numberone=intent.getStringExtra("num1");

String numbertwo=intent.getStringExtra("num2");

Double d1=Double.parseDouble(numberone);

Double d2=Double.parseDouble(numbertwo);

Double result=d1/d2;

textview.setText(numberone+" / "+numbertwo+" = "+result);

}

main.xml布局文件

<?xml version="1.0" encoding="utf-8"?>

android:orientation="vertical"