Java 如何从EditText和按钮/初始化对象填充ArrayList
您好,我如何使用Java 如何从EditText和按钮/初始化对象填充ArrayList,java,android,object,arraylist,android-arrayadapter,Java,Android,Object,Arraylist,Android Arrayadapter,您好,我如何使用EditText和按钮来填充我的ArrayList,问题是我不知道如何从EditText初始化对象,然后将其添加到我的ArrayList 多谢各位 //主要活动 public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInst
EditText
和按钮来填充我的ArrayList
,问题是我不知道如何从EditText
初始化对象,然后将其添加到我的ArrayList
多谢各位
//主要活动
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView view = (ListView)findViewById(R.id.listview);
EditText edit = (EditText)findViewById(R.id.editText);
Button button = (Button)findViewById(R.id.button);
Todo eat = new Todo("Eat ");
Todo sleep = new Todo("Sleep");
ArrayList<Todo> todolist = new ArrayList<>();
todolist.add(eat);
todolist.add(sleep);
Todoadapter adapter = new Todoadapter(this,R.layout.custom_adapter_layout,todolist);
view.setAdapter(adapter);
}
}
//ArrayAdapter
public class Todo {
private String todo;
public Todo(String todo) {
this.todo = todo;
}
public String getTodo() {
return todo;
}
public void setTodo(String todo) {
this.todo = todo;
}
}
public class Todoadapter extends ArrayAdapter<Todo> {
private Context mcontext;
int mresource;
private List<Todo> objects = new ArrayList<>();
public Todoadapter(@NonNull Context context, int resource, @NonNull ArrayList<Todo> objects) {
super(context, resource, objects);
this.mresource = resource;
this.mcontext = context;
this.objects = objects;
}
@NonNull
@Override
public View getView(final int position, @Nullable View convertView, @NonNull ViewGroup parent) {
String todo = getItem(position).getTodo();
LayoutInflater inflater = LayoutInflater.from(mcontext);
convertView = inflater.inflate(mresource, parent, false);
final CheckBox box = (CheckBox) convertView.findViewById(R.id.checkBox2);
box.setText(todo);
box.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(box.isChecked()){
//Delay to see animation
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
@Override
public void run() {
objects.remove(getItem(position)); //Your object list where you have the itens
notifyDataSetChanged(); //If you are using a recycler view.
}
},300); //adding 0.3 sec delay
}
}
});
return convertView;
}
}
公共类ToLoadAdapter扩展了ArrayAdapter{
私有上下文;
国际资源;
私有列表对象=新的ArrayList();
公共Todoadapter(@NonNull上下文,int资源,@NonNull ArrayList对象){
超级(上下文、资源、对象);
this.mresource=资源;
this.mcontext=上下文;
this.objects=对象;
}
@非空
@凌驾
公共视图getView(最终整数位置,@Nullable View convertView,@NonNull ViewGroup父级){
字符串todo=getItem(位置).getTodo();
LayoutFlater充气机=LayoutFlater.from(mcontext);
convertView=充气机。充气(mresource,父项,false);
最终复选框=(复选框)convertView.findViewById(R.id.checkBox2);
box.setText(todo);
setOnClickListener(新视图.OnClickListener(){
@凌驾
公共void onClick(视图v){
if(box.isChecked()){
//延迟观看动画
Handler=newhandler();
handler.postDelayed(新的Runnable(){
@凌驾
公开募捐{
objects.remove(getItem(position));//您的对象列表中有iten
notifyDataSetChanged();//如果您使用的是回收器视图。
}
},300);//添加0.3秒延迟
}
}
});
返回视图;
}
}
首先用XML或java为按钮添加侦听器
activity\u main
<Button ...
android:id="@+id/button"
android:onClick="addTodo"/>
在onCreate中添加上述代码,请记住,在将数据添加到todolist
之前,您必须验证编辑文本
数据,否则应用程序可能会崩溃。您好,谢谢您的回答我已经完成了您所说的所有操作,当我单击“添加”按钮时,我的应用程序正在关闭,它会显示“继续停止”@你能从logcatFATAL EXCEPTION发布错误详细信息吗?主要进程:com.example.alexandre.hei,PID:16153 java.lang.IllegalStateException:无法为android执行方法:onClick EDIT:将错误放入主post@Blebhebhe我很高兴能为您提供帮助,尽管您以前的方法,edittext和适配器的行为类似于局部变量,仅在oncreate中可用method@Blebhebhe不是真的,但是当您有一个需要稍后修改的对象(适配器、列表、todo)时,最好将它们保留在方法之外(特别是当它们是重对象时,如适配器、列表、按钮、edittext等)。谢谢,它起作用了!对不起,我似乎不能接受多重回答:(没关系,不用担心,我很乐意帮助你。
public class MainActivity extends AppCompatActivity {
// 1
private ArrayList<Todo> todolist;
private Todoadapter adapter;
private EditText edit;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView view = (ListView)findViewById(R.id.listview);
edit = (EditText)findViewById(R.id.editText);
Button button = (Button)findViewById(R.id.button);
Todo eat = new Todo("Eat ");
Todo sleep = new Todo("Sleep");
todolist = new ArrayList<>();
todolist.add(eat);
todolist.add(sleep);
adapter = new Todoadapter(this,R.layout.custom_adapter_layout,todolist);
view.setAdapter(adapter);
}
// 2
public void addTodo(View view){
// 3
todolist.add(new Todo(edit.getText().toString()));
// 4
adapter.notifyDataSetChanged();
}
}
buttonsetOnClickListener(new OnClickListener() {
public void onClick(View v) {
String data=edit.getText().toString();
if(data.isEmpty())
{
Toast.makeText(getApplicationContext(), "Please enter data", Toast.LENGTH_LONG).show();
return;
}
todolist.add(new Todo(data));
adapter.notifyDataSetChanged();
}
});