sqlite 如何将数据取到碎片中？

iaqfqrcu 于 2022-11-14 发布在 SQLite

关注(0)|答案(1)|浏览(166)

在主活动中，菜单指向片段BMICaclulator和History。BMICalculator片段有3个EditText、一个单选按钮和一个提交按钮。
Fragment_bmicalculator.xml：

<EditText
         android:id="@+id/height"/>
<EditText
         android:id="@+id/weight" />
<EditText
         android:id="@+id/age"/>

<RadioGroup xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/gender">
    <RadioButton
                android:id="@+id/gender_male"/>

     <RadioButton
                android:id="@+id/gender_female"/>
</RadioGroup>

<Button
        android:id="@+id/calculate"/>

插入到数据库工作。传递的数据是从editText和RadiButton*获取的。
BmiCalculator.java：

MyDatabaseHelper myDB = new MyDatabaseHelper(getActivity());
myDB.addData(height, weight, age, gender, bmiInterpretation);

MyDataBaseHelper.java：

private Context context;
    private static final String DATABASE_NAME = "bmi.db";
    private static final int DATABASE_VERSION = 1;
    private static final String TABLE_NAME = "bmiData";
    private static final String COLUMN_ID = "id";
    private static final String COLUMN_WEIGHT = "weight";
    private static final String COLUMN_HEIGHT = "height";
    private static final String COLUMN_AGE = "age";
    private static final String COLUMN_GENDER = "gender";
    private static final String COLUMN_BMI = "bmi";

public void onCreate(SQLiteDatabase db) {
        String query = "CREATE TABLE " + TABLE_NAME +
                " (" + COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                COLUMN_WEIGHT + " TEXT, " +
                COLUMN_HEIGHT + " TEXT, " +
                COLUMN_AGE + " TEXT, " +
                COLUMN_GENDER + " TEXT, " +
                COLUMN_BMI + " TEXT);";
        db.execSQL(query);
    }

void addData(String weight, String height, String age, String gender, String bmi){
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues cv = new ContentValues();

        cv.put(COLUMN_WEIGHT, weight);
        cv.put(COLUMN_HEIGHT, height);
        cv.put(COLUMN_AGE, age);
        cv.put(COLUMN_GENDER, gender);
        cv.put(COLUMN_BMI, bmi);
        long result = db.insert(TABLE_NAME,null, cv);
        if(result == -1){
            Toast.makeText(context, "Failed", Toast.LENGTH_SHORT).show();
        }else {
            Toast.makeText(context, "Added Successfully!", Toast.LENGTH_SHORT).show();
        }

如何在Fragment_HISTORY中获取数据并以列表的形式打印？回收视图和定制适配器使我的应用程序崩溃。

sqlite

来源：https://stackoverflow.com/questions/74419446/how-to-fetch-data-to-fragment

1条答案

按热度按时间

kxkpmulp1#

首先，我认为更好的方式是定义一个类，比方说数据：

public class Data{
    private String weight;
    private String height;
    private String age;
    private String gender;
    private String bmi;
    
    // Constructor, getter and setters ...
}

现在让我们定义一个返回SQLite数据库中所有数据的函数：

public List<Data> fetchData(){
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery("SELECT (weight, height, age, gender, bmi) FROM " + TABLE_NAME, null);
    List<Data> data = new ArrayList<Data>();
    if(cursor.moveToFirst()){
        do {
            data.add(new Data(cursor.getString(1), cursor.getString(2), cursor.getString(3), cursor.getString(4), cursor.getString(5)))
        }while(cursor.moveToNext())
    }
    cursor.close()
    return data;
}

现在，为了在您的ListView内部插入数据(在Fragment_HISTORY的布局中定义)，让我们假设XML文件中的ListView具有idlist_view，并且您为每个项定义了一个定制布局List_Item(用于显示数据的一个示例)。最后一步是创建一个适配器，并链接来自数据库和适配器的数据，例如：

// onViewCreated of fragment_history
@Override
public void onViewCreated(@NonNull View view, Bundle savedInstanceState) {
    ListView lw = view.findViewById(R.id.list_view);
    MyDatabaseHelper myDB = new MyDatabaseHelper(getActivity());
    List<Data> data = myDB.fetchData();
    ArrayAdapter<Data> adapter = new ArrayAdapter<>(getActivity(), R.layout.list_item, data);
    lw.setAdapter(adapter);
}

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sqlite 如何将数据取到碎片中？

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