以下是一个示例代码，演示如何从Android设备将输入的数据保存到MySQL数据库，并在保存成功后显示“数据保存成功”。

在Android端：

import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;

public class MainActivity extends AppCompatActivity {

    private EditText editTextName;
    private EditText editTextAge;
    private Button buttonSave;

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

        editTextName = findViewById(R.id.editTextName);
        editTextAge = findViewById(R.id.editTextAge);
        buttonSave = findViewById(R.id.buttonSave);

        buttonSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                saveData();
            }
        });
    }

    private void saveData(){
        final String name = editTextName.getText().toString().trim();
        final String age = editTextAge.getText().toString().trim();

        class SaveData extends AsyncTask {

            @Override
            protected String doInBackground(Void... voids) {
                try {
                    String link = "http://your-domain.com/save_data.php";
                    String data = URLEncoder.encode("name", "UTF-8") + "=" + URLEncoder.encode(name, "UTF-8");
                    data += "&" + URLEncoder.encode("age", "UTF-8") + "=" + URLEncoder.encode(age, "UTF-8");

                    URL url = new URL(link);
                    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                    conn.setDoOutput(true);
                    OutputStream outputStream = conn.getOutputStream();
                    outputStream.write(data.getBytes("UTF-8"));
                    outputStream.flush();
                    outputStream.close();

                    InputStream inputStream = conn.getInputStream();
                    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"));
                    String response = "";
                    String line = "";

                    while ((line = bufferedReader.readLine()) != null) {
                        response += line;
                    }

                    bufferedReader.close();
                    inputStream.close();
                    conn.disconnect();

                    return response;

                } catch (IOException e) {
                    e.printStackTrace();
                    return "Error: " + e.getMessage();
                }
            }

            @Override
            protected void onPostExecute(String result) {
                Toast.makeText(getApplicationContext(), result, Toast.LENGTH_LONG).show();
            }
        }

        SaveData saveData = new SaveData();
        saveData.execute();
    }
}

在服务器端（PHP）：

connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$sql = "INSERT INTO your-table-name (name, age) VALUES ('$name', '$age')";

if ($conn->query($sql) === TRUE) {
    echo "数据保存成功";
} else {
    echo "Error: " . $sql . "
" . $conn->error;
}

$conn->close();
?>

请注意，上述示例代码仅供参考，并且可能需要根据您的实际情况进行适当的修改。