Android电话拨号器实现方法

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  package="com.ljq.phone"
  android:versionCode="1"
  android:versionName="1.0">
 <application android:icon="@drawable/icon" android:label="@string/app_name">
  <activity android:name=".MainActivity"
     android:label="@string/app_name">
   <intent-filter>
    <action android:name="android.intent.action.MAIN" />
    <category android:name="android.intent.category.LAUNCHER" />
   </intent-filter>
  </activity>
 </application>
 <uses-sdk android:minSdkVersion="7" />
 <uses-permission android:name="android.permission.CALL_PHONE"/>
</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="vertical" android:layout_width="fill_parent"
 android:layout_height="fill_parent">
 <TextView android:layout_width="fill_parent"
  android:layout_height="wrap_content" 
  android:text="请输入电话号码" />
 <EditText android:layout_width="fill_parent"
  android:layout_height="wrap_content" 
  android:id="@+id/phone" />
 <Button android:layout_width="wrap_content"
  android:layout_height="wrap_content" 
  android:text="拔打此号码"
  android:id="@+id/button" />
</LinearLayout>

package com.ljq.phone;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity {
 private EditText phone=null;
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  phone=(EditText)this.findViewById(R.id.phone);
  Button button=(Button)this.findViewById(R.id.button);
  button.setOnClickListener(new View.OnClickListener(){
   public void onClick(View v) {
    String tel=phone.getText().toString();
    //方法一， 使用Intent目的： 激活android组件
    //Intent intent=new Intent();
    //intent.setAction("android.intent.action.CALL");
    //intent.setData(Uri.parse("tel:"+tel));
    //方法二
    Intent intent=new Intent("android.intent.action.CALL", Uri.parse("tel:"+tel));
    //方法的内部会自动为intent对象设置类别:android.intent.category.DEFAULT
    startActivity(intent);
   }
  });
 }
}