开发一个Android程序，利用它拨打电话和发送短信。

要在Android平台上开发一个能够拨打电话和发送短信的程序，可以使用Android提供的系统API和权限来实现。以下是一个简单的示例代码：

1. 添加权限到AndroidManifest.xml文件中

<uses-permission android:name="android.permission.CALL_PHONE" />
<uses-permission android:name="android.permission.SEND_SMS" />

2. 在Java代码中实现拨打电话和发送短信的功能

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Bundle;
import android.telephony.SmsManager;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

public class MainActivity extends AppCompatActivity {

    private static final int REQUEST_CALL_PHONE = 1;
    private static final int REQUEST_SEND_SMS = 2;

    private EditText phoneNumberEditText;
    private EditText messageEditText;
    private Button callButton;
    private Button sendMessageButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        phoneNumberEditText = findViewById(R.id.phone_number_edit_text);
        messageEditText = findViewById(R.id.message_edit_text);
        callButton = findViewById(R.id.call_button);
        sendMessageButton = findViewById(R.id.send_message_button);

        callButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String phoneNumber = phoneNumberEditText.getText().toString();
                Intent callIntent = new Intent(Intent.ACTION_CALL, Uri.parse("tel:" + phoneNumber));
                if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) {
                    ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.CALL_PHONE}, REQUEST_CALL_PHONE);
                } else {
                    startActivity(callIntent);
                }
            }
        });

        sendMessageButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String phoneNumber = phoneNumberEditText.getText().toString();
                String message = messageEditText.getText().toString();
                SmsManager smsManager = SmsManager.getDefault();
                if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.SEND_SMS) != PackageManager.PERMISSION_GRANTED) {
                    ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.SEND_SMS}, REQUEST_SEND_SMS);
                } else {
                    smsManager.sendTextMessage(phoneNumber, null, message, null, null);
                }
            }
        });
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        if (requestCode == REQUEST_CALL_PHONE) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                callButton.performClick();
            }
        } else if (requestCode == REQUEST_SEND_SMS) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                sendMessageButton.performClick();
            }
        }
    }
}

这个例子假设你在布局文件中使用了以下控件：

<EditText
    android:id="@+id/phone_number_edit_text"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Phone number" />

<EditText
    android:id="@+id/message_edit_text"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Message" />

<Button
    android:id="@+id/call_button"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Call" />

<Button
    android:id="@+id/send_message_button"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Send message" />

当你点击“Call”按钮时，它会检查是否有拨打电话的权限。如果没有，它会向用户请求该权限。如果用户授予了权限，它会创建一个意图，用于拨打指定的电话号码。

当你点击“Send message”按钮时，它将检查是否有发送短信的权限。如果没有，它会向用户请求该权限。如果用户授予了权限，它将使用SmsManager类发送短信到指定的电话号码。