Java 两个活动之间的共享arraylist不';行不通
我有一个问题,当我在checkedbox中选择我的项目时(因此它变成选中状态),数组已经填充,但当我单击“完成”时,称为新活动GenreViewActivity,它调用了获取上一个活动的arraylist的方法,但是它的ListView,布局是空的。我怎么了 AccountActivity.java:Java 两个活动之间的共享arraylist不';行不通,java,android,listview,android-activity,android-arrayadapter,Java,Android,Listview,Android Activity,Android Arrayadapter,我有一个问题,当我在checkedbox中选择我的项目时(因此它变成选中状态),数组已经填充,但当我单击“完成”时,称为新活动GenreViewActivity,它调用了获取上一个活动的arraylist的方法,但是它的ListView,布局是空的。我怎么了 AccountActivity.java: package com.example.msnma.movienotifier; import android.app.Activity; import android.content.Co
package com.example.msnma.movienotifier;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class AccountActivity extends AppCompatActivity
{
private static ArrayList <String> itemsChkStr = new ArrayList<String();
public class Item
{
boolean checked;
Drawable ItemDrawable;
String ItemString;
Item(/*Drawable drawable,*/ String t, boolean b)
{
//ItemDrawable = drawable;
ItemString = t;
checked = b;
}
public boolean isChecked()
{
return checked;
}
}
static class ViewHolder
{
CheckBox checkBox;
ImageView icon;
TextView text;
}
public class ItemsListAdapter extends BaseAdapter
{
private Context context;
private List<Item> list;
ItemsListAdapter(Context c, List<Item> l)
{
context = c;
list = l;
}
@Override
public int getCount()
{
return list.size();
}
@Override
public Object getItem(int position)
{
return list.get(position);
}
@Override
public long getItemId(int position)
{
return position;
}
public boolean isChecked(int position)
{
return list.get(position).checked;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent)
{
View rowView = convertView;
// reuse views
ViewHolder viewHolder = new ViewHolder();
if (rowView == null) {
LayoutInflater inflater = ((Activity)
context).getLayoutInflater();
rowView = inflater.inflate(R.layout.row, null);
viewHolder.checkBox = (CheckBox)
rowView.findViewById(R.id.rowCheckBox);
//viewHolder.icon = (ImageView)
rowView.findViewById(R.id.rowImageView);
viewHolder.text = (TextView)
rowView.findViewById(R.id.rowTextView);
rowView.setTag(viewHolder);
}
else
{
viewHolder = (ViewHolder) rowView.getTag();
}
//viewHolder.icon.setImageDrawable(list.get(position).ItemDrawable);
viewHolder.checkBox.setChecked(list.get(position).checked);
final String itemStr = list.get(position).ItemString;
viewHolder.text.setText(itemStr);
viewHolder.checkBox.setTag(position);
/*
viewHolder.checkBox.setOnCheckedChangeListener(
new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton
compoundButton, boolean b)
{
list.get(position).checked = b;
Toast.makeText(getApplicationContext(),
itemStr + "onCheckedChanged\nchecked: " + b,
Toast.LENGTH_LONG).show();
}
});
*/
viewHolder.checkBox.setOnClickListener(new
View.OnClickListener()
{
@Override
public void onClick(View view) {
boolean newState = !list.get(position).isChecked();
list.get(position).checked = newState;
Toast.makeText(getApplicationContext(),
itemStr + "setOnClickListener\nchecked: " + newState,
Toast.LENGTH_LONG).show();
}
});
viewHolder.checkBox.setChecked(isChecked(position));
return rowView;
}
}
Button btnLookup;
Button btnDone;
List<Item> items;
ListView listView;
ItemsListAdapter myItemsListAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_account);
listView = (ListView)findViewById(R.id.listview);
btnLookup = (Button)findViewById(R.id.lookup);
btnDone = (Button) findViewById(R.id.done);
initItems();
myItemsListAdapter = new ItemsListAdapter(this, items);
listView.setAdapter(myItemsListAdapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Toast.makeText(AccountActivity.this,
((Item)(parent.getItemAtPosition(position))).ItemString,
Toast.LENGTH_LONG).show();
}});
//Arraylist di tipo stringa con elementi checked
for (int i=0; i<items.size(); i++){
if (items.get(i).isChecked()){
//str += i + "\n";
itemsChkStr.add(items.get(i).ItemString);
}
}
btnLookup.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String str = "Check items:\n";
for (int i=0; i<items.size(); i++){
if (items.get(i).isChecked()){
//str += i + "\n";
str += items.get(i).ItemString;
}
}
/*
int cnt = myItemsListAdapter.getCount();
for (int i=0; i<cnt; i++){
if(myItemsListAdapter.isChecked(i)){
str += i + "\n";
}
}
*/
Toast.makeText(AccountActivity.this,
str,
Toast.LENGTH_LONG).show();
}
});
}
private void initItems(){
items = new ArrayList<Item>();
TypedArray arrayDrawable = getResources().obtainTypedArray(R.array.resicon);
TypedArray arrayText = getResources().obtainTypedArray(R.array.restext);
for(int i=0; i<arrayDrawable.length(); i++){
//Drawable d = arrayDrawable.getDrawable(i);
String s = arrayText.getString(i);
boolean b = false;
Item item = new Item(/*d,*/ s, b);
items.add(item);
}
arrayDrawable.recycle();
arrayText.recycle();
}
public void pressDoneButton(View view)
{
//itemsChecks();
Intent intent = new Intent(this, GenreViewActivity.class);
//EditText editText = (EditText) findViewById(R.id.editText);
//String message = editText.getText().toString();
//intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
/*public ArrayList <String> itemsChecks()
{
ArrayList <String> arrGenre = new ArrayList<String>();
for (int i=0; i<items.size(); i++){
if (items.get(i).isChecked()){
arrGenre.add(items.get(i).toString());
}
}
viewArray(arrGenre);
}*/
public static ArrayList <String> getSelectedString(){
return itemsChkStr;
}
}
/*@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_account);
Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
// Get a support ActionBar corresponding to this toolbar
ActionBar ab = getSupportActionBar();
// Enable the Up button
ab.setDisplayHomeAsUpEnabled(true);
}
public boolean onCreateOptionsMenu(Menu menu)
{
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_second, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings)
{
return true;
}
return super.onOptionsItemSelected(item);
}
public void pressAccountButton(MenuItem item) {
Intent intent = new Intent(this, AccountActivity.class);
//EditText editText = (EditText) findViewById(R.id.editText);
//String message = editText.getText().toString();
//intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}*/
package com.example.msnma.movienotifier;
导入android.app.Activity;
导入android.content.Context;
导入android.content.Intent;
导入android.content.res.TypedArray;
导入android.graphics.drawable.drawable;
导入android.os.Bundle;
导入android.support.v7.app.AppActivity;
导入android.view.LayoutInflater;
导入android.view.view;
导入android.view.ViewGroup;
导入android.widget.AdapterView;
导入android.widget.BaseAdapter;
导入android.widget.Button;
导入android.widget.CheckBox;
导入android.widget.ImageView;
导入android.widget.ListView;
导入android.widget.TextView;
导入android.widget.Toast;
导入java.util.ArrayList;
导入java.util.List;
公共类AccountActivity扩展了AppCompatActivity
{
private static ArrayList itemsChkStr=new ArrayList当然它将是空的。在尝试进行检查之前,您仅在begin中填写静态数组itemsChkStr。每次检查操作后,您需要更新静态检查列表。使用putStringArrayListExtra传递ArrayList
public void pressDoneButton(View view)
{
//itemsChecks();
Intent intent = new Intent(this, GenreViewActivity.class);
intent.putStringArrayListExtra("your_list",itemsChkStr);
startActivity(intent);
}
并使用intent.getStringArrayListExtra(“您的列表”)
获取ArrayList
public void pressDoneButton(View view)
{
//itemsChecks();
Intent intent = new Intent(this, GenreViewActivity.class);
intent.putStringArrayListExtra("your_list",itemsChkStr);
startActivity(intent);
}
在你的GenreViewActivity中
if(getIntent()!=null){
your_array_list = getIntent().getStringArrayListExtra("your_list");
}
你能清理你的代码吗?删除注释掉的代码code@user47845您需要在checkBox.setOnClickListener方法下添加这一行itemsChkStr.add(list.get(position.ItemString);
。实际上是:)
if(getIntent()!=null){
your_array_list = getIntent().getStringArrayListExtra("your_list");
}