android学习笔记002-拨打电话(优化)

package com.example.dailcall;

import android.support.v7.app.ActionBarActivity;
import android.text.TextUtils;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;//创建一个onClickListener接口的时候要导入这个包名
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;


public class MainActivity extends ActionBarActivity {

    // 定义组建
    private EditText et;
    private Button btn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et=(EditText) findViewById(R.id.et_number); //通过findViewById来查找组建名，绑定到定义的组建变量。
        btn=(Button) findViewById(R.id.btn_dail);
        btn.setOnClickListener(new MyClickListener());
      
    }
    
    private class MyClickListener implements OnClickListener{

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            
            callNumber();
            
        }
        
        
        
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
//把callNumber（）这个动作写成一个私有的方法
    private void callNumber() {
        Intent intent=new Intent();
        
        String number=et.getText().toString().trim();
        
        if (TextUtils.isEmpty(number)) {
            Toast.makeText(MainActivity.this, "电话号码不能为空！", 0).show();
            return;
        }
        
        intent.setAction(Intent.ACTION_CALL);
        intent.setData(Uri.parse("tel:"+number));
        
        startActivity(intent);
    }
}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    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.dailcall.MainActivity" >

    <EditText
        android:id="@+id/et_number"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:inputType="phone" >
        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/btn_dail"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/et_number"
        android:text="@string/dail" />

</RelativeLayout>