Android 如何将数据从一个活动发送到另一个listview?
嘿,伙计们,我正在android studio中开发一个应用程序。我有一个listview,当我做出选择时,我想将该选择添加到另一个不同活动中的listview。最简单/最好的方法是什么?我试过putExtra,但运气不好。任何例子或想法都很好。谢谢你们 谢谢大家的例子,他们帮助我更好地理解了意图系统。我一直在尝试不同的例子,每个人都张贴,我有点被卡住了。目标只是让我从Walmart.java文件的listview中选择的项目显示在GiftsSelected.java的listview中。我有另一个地方可以打开活动,所以我不需要它来立即打开新活动。 这是我的密码: 这是Walmart.javaAndroid 如何将数据从一个活动发送到另一个listview?,android,Android,嘿,伙计们,我正在android studio中开发一个应用程序。我有一个listview,当我做出选择时,我想将该选择添加到另一个不同活动中的listview。最简单/最好的方法是什么?我试过putExtra,但运气不好。任何例子或想法都很好。谢谢你们 谢谢大家的例子,他们帮助我更好地理解了意图系统。我一直在尝试不同的例子,每个人都张贴,我有点被卡住了。目标只是让我从Walmart.java文件的listview中选择的项目显示在GiftsSelected.java的listview中。我有另
public class Walmart extends ActionBarActivity {
private String[]giftarray = {
"Apple" ,
"Bananas",
"Bed",
"Beef",
"Bottle",
"Bread",
"Broccoli",
"Carrots",
"Cat",
"Chicken",
"Chocolate",
"Computer",
"Cow",
"Crow",
"Dog",
"Dolphin",
"Dove",
"Drawer",
"Egg",
"Fish",
"Fork",
"Fridge",
"Giraffe",
};
Intent a = new Intent(Walmart.this,GiftsSelected.class);
private ListView giftListView;
private ArrayAdapter arrayAdapter;
ArrayList<String> list = new ArrayList<String>();
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo){}
public boolean onContextItemSelected(MenuItem item){
return true;
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_walmart);
getSupportActionBar().hide();
giftListView = (ListView) findViewById(R.id.gift_list1);
arrayAdapter = new ArrayAdapter(this, android.R.layout.simple_gallery_item, giftarray );
giftListView.setAdapter(arrayAdapter);
giftListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String item = "Item added to registry";
list.add(item2);
a.putStringArrayListExtra("list",list);
Toast.makeText(getBaseContext(), item, Toast.LENGTH_LONG).show();
}
});
}
公共类沃尔玛扩展了ActionBarActivity{
私有字符串[]giftarray={
“苹果”,
“香蕉”,
“床”,
“牛肉”,
“瓶子”,
“面包”,
“西兰花”,
“胡萝卜”,
“猫”,
“鸡”,
“巧克力”,
“计算机”,
“奶牛”,
“乌鸦”,
“狗”,
“海豚”,
“鸽子”,
“抽屉”,
“鸡蛋”,
“鱼”,
“叉子”,
“冰箱”,
“长颈鹿”,
};
意向a=新意向(Walmart.this,GiftsSelected.class);
私有ListView giftListView;
专用阵列适配器阵列适配器;
ArrayList=新建ArrayList();
public void onCreateContextMenu(ContextMenu菜单,视图v,ContextMenu.ContextMenuInfo菜单信息){}
公共布尔值onContextItemSelected(MenuItem项){
返回true;
}
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_沃尔玛);
getSupportActionBar().hide();
giftListView=(ListView)findViewById(R.id.gift\u list1);
arrayAdapter=新的arrayAdapter(这个,android.R.layout.simple\u gallery\u项目,giftarray);
giftListView.setAdapter(arrayAdapter);
giftListView.setOnItemClickListener(新的AdapterView.OnItemClickListener(){
@凌驾
public void onItemClick(AdapterView父对象、视图、整型位置、长id){
String item=“添加到注册表的项目”;
增加(第2项);
a、 putStringArrayListExtra(“列表”,列表);
Toast.makeText(getBaseContext(),item,Toast.LENGTH_LONG.show();
}
});
}
这是我的GiftsSelected.java代码:
public class GiftsSelected extends ActionBarActivity {
private ListView giftListView;
private ArrayAdapter arrayAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
ArrayList<String> list = new ArrayList<String>();
//This makes my app crash which makes me think I did this wrong...
list = getIntent().getStringArrayListExtra("list");
String[] giftarray = new String[list.size()];
list.toArray(giftarray);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_gifts_selected);
getSupportActionBar().hide();
giftListView = (ListView) findViewById(R.id.gift_list1);
arrayAdapter = new ArrayAdapter(this, android.R.layout.simple_gallery_item, giftarray);
giftListView.setAdapter(arrayAdapter);
giftListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String item = "Item added to your registry";
Toast.makeText(getBaseContext(), item, Toast.LENGTH_LONG).show();
}
});
}
public class giftselected扩展了ActionBarActivity{
私有ListView giftListView;
专用阵列适配器阵列适配器;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
ArrayList=新建ArrayList();
//这让我的应用程序崩溃,这让我觉得我做错了。。。
list=getIntent().getStringArrayListExtra(“列表”);
String[]giftarray=新字符串[list.size()];
托雷(吉夫塔雷);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity\u已选择);
getSupportActionBar().hide();
giftListView=(ListView)findViewById(R.id.gift\u list1);
arrayAdapter=新的arrayAdapter(这个,android.R.layout.simple\u gallery\u项目,giftarray);
giftListView.setAdapter(arrayAdapter);
giftListView.setOnItemClickListener(新的AdapterView.OnItemClickListener(){
@凌驾
public void onItemClick(AdapterView父对象、视图、整型位置、长id){
String item=“添加到注册表的项目”;
Toast.makeText(getBaseContext(),item,Toast.LENGTH_LONG.show();
}
});
}
这是我使用的列表
ArrayList<String> list = new ArrayList<String>();
在第一个活动中
Intent i=new Intent(FirstActivity.this,SecondActivity.class);
i.putStringArrayListExtra("list",list);
startActivity(i);
在onCreate中的第二个活动中
list = getIntent().getStringArrayListExtra("list");
a) 您可以将listview项对象包裹起来,并通过intent extra在活动之间发送它。
b) 您可以将所选listview项保存在全局变量中。(不推荐)假设第一个活动是X,X持有一个listview,该listview更新活动Y中的另一个listview 如果X与Y紧密相关,也就是说Y启动X,获取数据然后立即返回Y,那么您应该使用Y的
startActivityForResult
class ActivityY {
public static final int REQUEST_CODE = 2;
...
Intent i = new Intent(this, ActivityX.class);
startActivityForResult(i, REQUEST_CODE);
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_CODE) {
if (resultCode == RESULT_OK) {
String returndata = data.getStringExtra("rowdata");
//update your listView, do notifyDataSetChanged() etc;
}
}
}
}
class ActivityX {
// in listview onItemClickListener or elsewhere that listens to row click
Intent intent = new Intent();
returnIntent.putExtra("rowdata", rowdata); // whatever data you need to transfer
setResult(RESULT_OK,intent);
finish();
}
如果X和Y是松散相关的,也就是说X不一定从Y启动,而是转到Y,那么您应该只使用通常的startActivity(intent)
如果X和Y是完全独立的,也就是说X不一定是从Y启动的,在到达Y之前可能不会转到Y或漫游其他活动,则应缓存数据。如果数据大小较小,则最好将其存储在中。当Y活动开始时,获取数据,更新ListView,然后在需要时删除cac从首选项中删除数据
class ActivityY {
public static final int REQUEST_CODE = 2;
...
Intent i = new Intent(this, ActivityX.class);
startActivityForResult(i, REQUEST_CODE);
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_CODE) {
if (resultCode == RESULT_OK) {
String returndata = data.getStringExtra("rowdata");
//update your listView, do notifyDataSetChanged() etc;
}
}
}
}
class ActivityX {
// in listview onItemClickListener or elsewhere that listens to row click
Intent intent = new Intent();
returnIntent.putExtra("rowdata", rowdata); // whatever data you need to transfer
setResult(RESULT_OK,intent);
finish();
}