练习用内部类方式设置点击事件来实现直接拨打电话功能

package com.hanqi.dianhuabohaoqi;

import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    EditText et_number;
    Button bt_1;
    String number;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bt_1=(Button)findViewById(R.id.bt_1);
        et_number=(EditText)findViewById(R.id.et_number);
        bt_1.setOnClickListener(new callphone());
    }

    class callphone implements View.OnClickListener
    {
        public void onClick(View v)
        {
           switch (v.getId())
           {
               case R.id.bt_1:
                   number=et_number.getText().toString().trim();
                   if (number.length()==0)
                   {
                       Toast.makeText(MainActivity.this, "请输入电话号码", Toast.LENGTH_SHORT).show();
                   }
                   if (number==null)return;
                   Intent intent = new Intent(Intent.ACTION_CALL);
                   Uri uri=Uri.parse("tel:"+number);
                   intent.setData(uri);
                   try {
                       startActivity(intent);
                   }catch (Exception e)
                   {
                       e.printStackTrace();
                   }
                   break;
           }
        }

    }

}

<?xml version="1.0" encoding="utf-8"?>
<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.hanqi.dianhuabohaoqi.MainActivity">

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

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="拨打电话"
        android:id="@+id/bt_1"
        android:layout_alignRight="@+id/et_number"
       />
</RelativeLayout>