按钮在android basic apo中不起作用我正在尝试创建

Question

我的第一个应用出现了问题。当我点击“提交”时，它的意思是用用户输入的值创建一个文本文件，但它并没有创建它。我不确定问题出在哪里。

我还想知道是否有更好的方法来存储用户输入的数据，使其最终在excel电子表格中可用。或者仅仅使用纯文本文件来使其更容易？

package com.example.mybodyrecord;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import androidx.appcompat.app.AppCompatActivity;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class MainActivity extends AppCompatActivity {

    String myBodyRecord = "My_Body_Record.txt";
    Date date = new Date();
    SimpleDateFormat formatter = new SimpleDateFormat("dd-MM-yyyy HH:mm");
    File file; // declare here and initialize inside onCreate.

    Button button;

    EditText weightInput;
    EditText ketoneBloodInput;
    EditText ketoneUrineInput;
    EditText bloodPressureInput;
    EditText bloodSugarInput;

    String weight;
    String ketoneBlood;
    String ketoneUrine;
    String bloodPressure;
    String bloodSugar;


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

        //Setting where to get the data from, ie what fields
        weightInput = findViewById(R.id.weight);
        ketoneBloodInput = findViewById(R.id.ketoneblood);
        ketoneUrineInput = findViewById(R.id.ketoneurine);
        bloodPressureInput = findViewById(R.id.bp);
        bloodSugarInput = findViewById(R.id.bslvl);

        button = findViewById(R.id.submit);

        //activity has a context now you can use getApplicationContext or this
        file = new File(this.getFilesDir(),myBodyRecord);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                FileOutputStream fos = null;

                //Taking input from the fields
                weight = weightInput.getText().toString() +"kg";
                ketoneBlood = ketoneBloodInput.getText().toString() +"mmol/L";
                ketoneUrine = ketoneUrineInput.getText().toString();
                bloodPressure = bloodPressureInput.getText().toString() +"mmHg";
                bloodSugar = bloodSugarInput.getText().toString() +"mmol/L";

                //Save to the file, with the date and time
                if (file.exists()) {
                    try {
                        fos = openFileOutput(myBodyRecord, getApplicationContext().MODE_APPEND);
                        fos.write("\n\r".getBytes());
                        fos.write(formatter.format(date).getBytes());
                        fos.write(weight.getBytes());
                        fos.write(ketoneBlood.getBytes());
                        fos.write(ketoneUrine.getBytes());
                        fos.write(bloodPressure.getBytes());
                        fos.write(bloodSugar.getBytes());

                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    finally {
                        try {
                            fos.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
                else {
                    try {
                        fos = openFileOutput(myBodyRecord, getApplicationContext().MODE_PRIVATE);
                        fos.write("\n\r".getBytes());
                        fos.write(formatter.format(date).getBytes());
                        fos.write(weight.getBytes());
                        fos.write(ketoneBlood.getBytes());
                        fos.write(ketoneUrine.getBytes());
                        fos.write(bloodPressure.getBytes());
                        fos.write(bloodSugar.getBytes());

                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    finally {
                        try {
                            fos.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
        });
    }
}

Answer 1

柯林斯

如何在android中读/写文本文件的问题已经在这个帖子中得到了回答：

How can I read a text file in Android?

然而，这并不是你在android中想要的。首先，您应该熟悉应用程序和服务的概念。然后，为了解决你的问题：

• 适用于较少的数据量(例如设置)您可以使用SharedPreferences.
• For more data (设置更多数据)。记录)推荐的方法是具有SQLite数据库的ContentProvider。