我正在尝试为OnClickListener
的每个项目设置一个ListView
,以更新或删除SQLite数据库中的每个项目
列表项布局
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:background="@color/grisFondo"
android:padding="10dp">
<ImageView
android:id="@+id/imagencoche"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
tools:srcCompat="@tools:sample/avatars" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:gravity="center"
android:orientation="horizontal">
<TextView
android:id="@+id/nombreCoche"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center"
android:text="TextView" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:gravity="bottom"
android:orientation="horizontal">
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Button" />
<Button
android:id="@+id/button4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Button"
android:onclick="guardarCordenadas"/>
</LinearLayout>
</LinearLayout>
</LinearLayout>
模型类,为简单起见,我没有粘贴getter和setters
public class Coche {
int id;
float longitud;
float latitud;
Bitmap foto;
String nombre;
public Coche(Bitmap foto, String nombre) {
this.foto = foto;
this.nombre = nombre;
}
public Coche(int id, float longitud, float latitud, Bitmap foto, String nombre) {
this.id = id;
this.longitud = longitud;
this.latitud = latitud;
this.foto = foto;
this.nombre = nombre;
}
这是我的适配器类
public class MiAdaptador extends BaseAdapter {
private Context context;
private int layout;
private ArrayList<Coche>lista;
public MiAdaptador(Context context, int layout, ArrayList<Coche> lista) {
this.context = context;
this.layout = layout;
this.lista = lista;
}
@Override
public int getCount() {
return lista.size();
}
@Override
public Object getItem(int position) {
return lista.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
private class ViewHolder{
ImageView imageView;
TextView nom;
}
@Override
public View getView(int position, View view, ViewGroup parent) {
View fila=view;
ViewHolder holder=new ViewHolder();
if(fila==null)
{
LayoutInflater inflater=(LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
fila=inflater.inflate(layout,null);
holder.imageView=fila.findViewById(R.id.imagencoche);
holder.nom=fila.findViewById(R.id.nombreCoche);
fila.setTag(holder);
}
else{
holder=(ViewHolder)fila.getTag();
}
Coche coche=lista.get(position);
holder.nom.setText(coche.getNombre());
holder.imageView.setImageBitmap(coche.getFoto());
return fila;
}
}
显示ListView
public class TodosLosCoches extends AppCompatActivity{
ArrayList<Coche> lista;
ListView listview;
MiAdaptador adapter=null;
ImageView imageviewicon;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_todos_los_coches);
//setListAdapter(new MiAdaptador(this,lista));
listview=findViewById(R.id.list);
MyOpenHelper db=new MyOpenHelper(this);
lista=db.selectCoches();
adapter=new MiAdaptador(this, R.layout.itemcoche,lista);
listview.setAdapter(adapter);
adapter.notifyDataSetChanged();
}
}
列表视图活动的xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".TodosLosCoches">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:id="@+id/button6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Button" />
<Button
android:id="@+id/button7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Button" />
</LinearLayout>
<ListView
android:id="@+id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:dividerHeight="5dp" />
</LinearLayout>
这是SQLite助手类
public class MyOpenHelper extends SQLiteOpenHelper {
public static final int DATABASE_VERSION = 1;
public static final String DATABASE_NAME = "BuscaCoches.db";
public static final String CREAR_TUSU = "CREATE TABLE usuarios (_id INTEGER PRIMARY KEY AUTOINCREMENT, nombre TEXT, pwd TEXT)";
public static final String CREAR_TCOCHE = "CREATE TABLE coches(_id INTEGER PRIMARY KEY AUTOINCREMENT,nombre TEXT, longitud REAL, latitud REAL,foto BLOB)";
public MiAdaptador adapter;
public MyOpenHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREAR_TUSU);
db.execSQL(CREAR_TCOCHE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
//metodo para seleccionar el usuario de la BBDD al solo haber un usuario no usamos un bucle
public Usuario getUsu()
{
Usuario usu=null;
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery("SELECT nombre,pwd,_id FROM usuarios ", null);
if (c.moveToFirst()){
//recogemos valores
String nom = c.getString(0);
int pwd = c.getInt(1);
int id=c.getInt(2);
//creamos usuario a devolver
usu = new Usuario(id,nom,pwd);
}
c.close();
db.close();
return usu;
}
public boolean hayCoches()
{
SQLiteDatabase db=this.getWritableDatabase();
Cursor c =db.rawQuery("SELECT nombre from coches", null);
if(c.getCount()>0)
{
c.close();
return true;
}
c.close();
return false;
}
public void setUsu(Usuario u)
{
SQLiteDatabase db = this.getWritableDatabase();
ContentValues cv =new ContentValues();
cv.put("nombre",u.getNombre());
cv.put("pwd",u.getPwd());
db.insert("usuarios", null, cv);
db.close();
}
public ArrayList<Coche> selectCoches(){
ArrayList<Coche> lista =new ArrayList<Coche>();
SQLiteDatabase db=this.getReadableDatabase();
Cursor c =db.rawQuery("SELECT nombre, foto, longitud, latitud,_id from coches", null);
if (c.moveToFirst()){
do {
//recogemos valores
String nom = c.getString(0);
byte[] foto = c.getBlob(1);
float longitud = c.getFloat(2);
float latitud = c.getFloat(3);
int id = c.getInt(4);
Coche coche = new Coche(id, longitud, latitud, DbBitMapUtility.getImage(foto), nom);
lista.add(coche);
}while(c.moveToNext());
}
return lista;
}
public void setCar(Coche c )
{
SQLiteDatabase db= this.getWritableDatabase();
ContentValues cv =new ContentValues();
cv.put("nombre",c.getNombre());
cv.put("foto",DbBitMapUtility.getBytes(c.getFoto()));
db.insert("coches", null, cv);
db.close();
}
public static void borrar(Context c)
{
c.deleteDatabase(DATABASE_NAME);
}
}
我无法实现对ListView
项目上的按钮进行更新或删除项目列表的DB中的条目。
答案 0 :(得分:2)
在每个项目上设置点击事件的最简单方法是
yourListView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,long id) {
// here you can do what you want based on the position or id
}
});
答案 1 :(得分:1)
在您的适配器中,在getView()方法内设置clickListenerholder.nom
holder.nom.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// do something
}
});
希望这会对您有所帮助。
答案 2 :(得分:0)
我已添加
holder.borrar.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
MyOpenHelper db=new MyOpenHelper(context);
db.borrarCoche(position+"");
notifyDataSetChanged();
}
});
它从BBDD中删除了该项目,但即使我添加了notifyDataSetChanged(),列表视图也不会改变。