作为 Android 开发的新手，我已经在这个问题上被困了几个星期了，而且越来越累了。
在查看了每个教程并阅读了我能找到的每个问题和答案之后，我仍然不知道如何让 Android Studio 只获取 SQLite 数据库中的内容并将其内容粘贴到listview。我本以为会有一个android:displayallfrom("myDB")XML 文件中的某种命令仅显示数据库中的所有内容，但它似乎要复杂得多。
基本上，我想做的是显示我的数据库中的所有数据 (Dogs.db）到我的listview (list_dogs）在我的选项卡视图的第一个选项卡中（Tab1).
这是我的代码：
Tab1.java
package com.example.major.awoo;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Tab1 extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.tab1, container, false);
return rootView;
}
}
tab1.xml
<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.example.major.awoo.MainActivity">
<ListView
android:id="@+id/list_dogs"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:listSelector=""/>
</RelativeLayout>
数据库助手.java
package com.example.major.awoo;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DatabaseHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "Dogs.db";
public static final String TABLE_NAME = "dogs_table";
public static final String COL_1 = "ID";
public static final String COL_2 = "NAME";
public static final String COL_3 = "AGE";
public static final String COL_4 = "WEIGHT";
public static final String COL_5 = "BREED";
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table " + TABLE_NAME +" (ID INTEGER PRIMARY KEY AUTOINCREMENT,NAME TEXT,SURNAME TEXT,MARKS INTEGER)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS "+TABLE_NAME);
onCreate(db);
}
public boolean insertData(String name,String age,String weight,String breed) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COL_2,name);
contentValues.put(COL_3,age);
contentValues.put(COL_4,weight);
contentValues.put(COL_5,breed);
long result = db.insert(TABLE_NAME, null, contentValues);
if(result == -1)
return false;
else
return true;
}
public Cursor getAllData() {
SQLiteDatabase db = this.getWritableDatabase();
Cursor res = db.rawQuery("select * from "+TABLE_NAME,null);
return res;
}
public boolean updateData(String id,String name,String age,String weight,String breed) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COL_1,id);
contentValues.put(COL_2,name);
contentValues.put(COL_3,age);
contentValues.put(COL_4,weight);
contentValues.put(COL_5,breed);
db.update(TABLE_NAME, contentValues, "ID = ?",new String[] { id });
return true;
}
public Integer deleteData (String id) {
SQLiteDatabase db = this.getWritableDatabase();
return db.delete(TABLE_NAME, "ID = ?",new String[] {id});
}
public Cursor getListContents(){
SQLiteDatabase db = this.getWritableDatabase();
Cursor data = db.rawQuery("SELECT * FROM " + TABLE_NAME,null);
return data;
}
//method to display data
public Cursor displayData;
{
SQLiteDatabase db = this.getWritableDatabase();
Cursor res = db.rawQuery(" SELECT * FROM " + TABLE_NAME, null);
return res;
}
}
我确信我缺少一些非常愚蠢的东西，但任何帮助将不胜感激。
