效果图：

package jk.phone;import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;public class MainActivity extends Activity {protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);Button button = (Button)this.findViewById(R.id.callButton);button.setOnClickListener(new ButtonOnClickListener());}
private final class ButtonOnClickListener implements OnClickListener{@Overridepublic void onClick(View v) {EditText mobileText =(EditText)findViewById(R.id.mobileText);String mobileNumber = mobileText.getText().toString();Intent intent = new Intent();intent.setAction("android.intent.action.CALL");intent.setData(Uri.parse("tel:"+mobileNumber));startActivity(intent);}
}@Overridepublic 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;}}

activity_main.xml

<LinearLayout 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"android:orientation="vertical"tools:context=".MainActivity" ><TextViewandroid:id="@+id/textView1"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="@string/mobileText" /><EditTextandroid:id="@+id/mobileText"android:layout_width="fill_parent"android:layout_height="wrap_content"android:ems="10"></EditText><Buttonandroid:id="@+id/callButton"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="@string/callButton" /></LinearLayout>

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources><string name="app_name">Phone</string><string name="action_settings">Settings</string><string name="callButton">拨号</string><string name="mobileText">请输入要拨打的号码</string>
</resources>

androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"package="jk.phone"android:versionCode="1"android:versionName="1.0" ><uses-sdkandroid:minSdkVersion="8"android:targetSdkVersion="18" /><uses-permission android:name="android.permission.CALL_PHONE"/><applicationandroid:allowBackup="true"android:icon="@drawable/ic_launcher"android:label="@string/app_name"android:theme="@style/AppTheme" ><activityandroid:name="jk.phone.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>
</manifest>