我刚接触Android开发,想问一下如何正确地解决以下问题。我制作了一个杂货清单应用程序,可以显示数量、物品名称和状态(复选框)。以下是我的问题:
- 清单上的物品或物品名称没有显示出来。
- 标题(QUANTITY,ITEM和STATUS)和按钮(添加,删除)重复了,不应该这样。
- 最后,我应该在哪里放置按钮(additem)的代码才能进入其预定布局。它应该放在GroceryListActivity类还是Grocery类中?
如果我有很多问题,对不起,如果您能回答这些问题,我将不胜感激。谢谢!:)
Grocery Model Class
public class Grocery{
private String quantity;
private String item;
private boolean selected;
//quantity
public Grocery(String quantity, String item) {
this.quantity = quantity;
selected = false;
}
public String getQuantity() {
return quantity;
}
public void setQuantity(String quantity) {
this.quantity = quantity;
}
//item
public Grocery(String item) {
this.item = item;
selected = false;
}
public String getItem() {
return item;
}
public void setItem(String item) {
this.item = item;
}
//chckbox
public boolean isSelected() {
return selected;
}
public void setSelected(boolean selected) {
this.selected = selected;
}
}
购物清单活动
import java.util.ArrayList;
import java.util.List;
import android.app.AlertDialog;
import android.app.ListActivity;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Toast;
public class GroceryListActivity extends ListActivity implements OnClickListener{
/** Called when the activity is first created. */
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
// Create an array of Strings, that will be put to our ListActivity
ArrayAdapter<Grocery> adapter = new ArrayAdapterGroceryList(this, getGrocery());
setListAdapter(adapter);
}
private List<Grocery> getGrocery() {
List<Grocery> list = new ArrayList<Grocery>();
list.add(get("1", "Soy Sauce"));
list.add(get("2", "Cabbage"));
list.add(get("3", "Potato"));
list.add(get("4", "Bell Pepper"));
// Initially select one of the items
list.get(1).setSelected(false);
return list;
}
private Grocery get(String q, String i) {
return new Grocery(q, i);
}
public void onCreate1(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.addgrocery);
Button addItem_btn = (Button) findViewById(R.id.addItem);
addItem_btn.setOnClickListener((OnClickListener) this);
Button delete_btn = (Button) findViewById(R.id.deleteItem);
delete_btn.setOnClickListener(this);
}
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.addItem:
Intent a = new Intent(this, AddGrocery.class);
startActivity(a);
break;
case R.id.deleteItem:
AlertDialog.Builder Builder = new AlertDialog.Builder(this);
Builder.setTitle("Confirm Delete.");
Builder.setMessage("Are you sure you want to delete selected items?");
Builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(getApplicationContext(), "You clicked on YES", Toast.LENGTH_SHORT).show();
}
});
Builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(getApplicationContext(), "You clicked on NO", Toast.LENGTH_SHORT).show();
dialog.cancel();
}
});
Builder.show();
break;
}
}
}
数组适配器
import java.util.List;
import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.TextView;
public class ArrayAdapterGroceryList extends ArrayAdapter<Grocery> {
private final List<Grocery> list;
private final Activity context;
public ArrayAdapterGroceryList(Activity context, List<Grocery> list) {
super(context, R.layout.grocery, list);
this.context = context;
this.list = list;
}
static class ViewHolder {
protected TextView itemQty;
protected TextView itemName;
protected CheckBox chkItem;
public TextView textQty;
public TextView textName;
public CheckBox checkbox;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = null;
if (convertView == null) {
LayoutInflater inflator = context.getLayoutInflater();
view = inflator.inflate(R.layout.grocery, null);
final ViewHolder viewHolder = new ViewHolder();
viewHolder.textQty = (TextView) view.findViewById(R.id.itemQty);
viewHolder.textName = (TextView) view.findViewById(R.id.itemName);
viewHolder.checkbox = (CheckBox) view.findViewById(R.id.chkItem);
viewHolder.checkbox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
Grocery element = (Grocery) viewHolder.checkbox.getTag();
element.setSelected(buttonView.isChecked());
}
});
view.setTag(viewHolder);
viewHolder.checkbox.setTag(list.get(position));
} else {
view = convertView;
((ViewHolder) view.getTag()).checkbox.setTag(list.get(position));
}
ViewHolder holder = (ViewHolder) view.getTag();
holder.textQty.setText(list.get(position).getQuantity());
holder.textName.setText(list.get(position).getItem());
holder.checkbox.setChecked(list.get(position).isSelected());
return view;
}
}
我的XML文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@layout/bg_list"
android:orientation="vertical"
android:weightSum="1.0">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:weightSum="3"
android:gravity="center"
android:background="@layout/bg_box">
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:text="QTY"
android:textColor="#ffffff"
android:textSize="20dp"
android:textStyle="bold"
android:layout_weight="1" />
<TextView
android:id="@+id/serialNumberView"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:layout_weight="1"
android:text="ITEM"
android:textStyle="bold"
android:textColor="#ffffff"
android:textSize="20dp"/>
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:text="STATUS"
android:textStyle="bold"
android:textColor="#ffffff"
android:textSize="20dp"
android:layout_weight="1" />
</LinearLayout>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_weight="1"
android:paddingTop="5dp"
android:gravity="center_horizontal">
<TextView android:id="@+id/itemQty"
android:layout_width="30dp"
android:layout_height="fill_parent"
android:paddingLeft="20dp"
android:textColor="#FFFFFF"
android:textSize="15dp"/>
<TextView android:id="@+id/itemName"
android:layout_width="200dp"
android:layout_height="fill_parent"
android:textColor="#FFFFFF"
android:textSize="15dp"/>
<CheckBox
android:id="@+id/chkItem"
android:layout_width="50dp"
android:layout_height="fill_parent"/>
</LinearLayout>
</ScrollView>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_gravity="bottom">
<Button
android:id="@+id/addItem"
android:layout_width="0dp"
android:layout_height="fill_parent"
android:text="Add"
android:layout_weight="1" />
<Button
android:id="@+id/deleteItem"
android:layout_width="0dp"
android:layout_height="fill_parent"
android:text="Delete"
android:layout_weight="1" />
</LinearLayout>
ListView
,制作其中需要的视图的列表项。然后将arraylist List<Grocery>
传递给该适配器..简单吧..只需查看一些关于CustomListView的教程,你会发现它很容易实现,而不是你正在做的复杂操作。 - user370305