android 实现拨号功能，让用户选择是否拨号，不自动拨号

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <EditText
        android:id="@+id/phone"
        android:layout_width="match_parent"
        android:layout_height="25dp"
        android:hint="请输入手机号" />
    <Button
        android:id="@+id/cal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="onClick"
        android:text="拨号"/>
</LinearLayout>

MainActivity.java

package com.example.teletephone;
import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
public class MainActivity extends AppCompatActivity  implements View.OnClickListener{
    private EditText phone;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        phone= (EditText) findViewById(R.id.phone);
    }
    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.cal:
                Intent intent = new Intent(Intent.ACTION_DIAL);
                intent.setData(Uri.parse("tel:"+phone.getText()));
                startActivity(intent);//内部类
                break;
        }
    }
}