Question

我试图在Android中制作待办事项列表应用。这是我的代码

MainActivity.java

import com.vrishankgupta.adapter.myPkg.listClass;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    ArrayList<listClass> arr = new ArrayList<listClass>(0);
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        arr.add(new listClass("Task 1",false));
        arr.add(new listClass("Task 2",true));
        arr.add(new listClass("Task 3",true));
        arr.add(new listClass("Task 4",false));
        final CustomAdapter adapter = new CustomAdapter(this,arr);
       final ListView lv = findViewById(R.id.vishulv);
        Log.e("Task 1", arr.get(0).isActive()+"" );
        lv.setAdapter(adapter);
        final EditText etnew = findViewById(R.id.etNew);
        Button add = findViewById(R.id.addButn);


        add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(etnew.getText()==null || etnew.getText().toString().equals(""))
                {
                    Toast.makeText(getApplicationContext(),"Enter data",Toast.LENGTH_LONG).show();
                }

                else
                {
                    arr.add(new listClass(etnew.getText().toString(),false));
                    CustomAdapter adapter = new CustomAdapter(MainActivity.this,arr);
                    final ListView lv = findViewById(R.id.vishulv);
                    lv.setAdapter(adapter);
                    etnew.setText("");
                }

            }
        });

    }
}

CustomAdapter

package com.vrishankgupta.adapter;

public class CustomAdapter extends ArrayAdapter<listClass> {

ArrayList<listClass> arr;

public CustomAdapter(@NonNull Context context, ArrayList<listClass> arr) {
    super(context,R.layout.detail, arr);
    this.arr = new ArrayList<listClass>(0);
    this.arr.addAll(arr);

}



@NonNull
@Override
public View getView(final int position, @Nullable View convertView, @NonNull final ViewGroup parent) {
    final ViewHolder holder;
    if(convertView == null)
    {
        holder = new ViewHolder();
        convertView = LayoutInflater.from(getContext()).inflate(R.layout.detail,parent,false);
        holder.textview = (TextView)convertView.findViewById(R.id.todoTaskTV);
        holder.checkBox = (CheckBox)convertView.findViewById(R.id.checkBut);
        holder.button = (Button)convertView.findViewById(R.id.delBut);
        convertView.setTag(holder);

    }

    else
    {
        holder = (ViewHolder)convertView.getTag();
    }



    listClass task = arr.get(position);
    Log.e("Checking", position + task.getTask().toString() );
    holder.textview.setText(task.getTask());
    holder.checkBox.setChecked(task.isActive());
    holder.checkBox.setTag(task);
    holder.button.setTag(task);
    notifyDataSetChanged();


    holder.checkBox.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            CheckBox cb = (CheckBox)v;
            listClass task = (listClass) cb.getTag();
            Toast.makeText(getContext(),"Checkbox",Toast.LENGTH_LONG).show();
            task.setActive(cb.isChecked());
            Log.e("isActive Task1", arr.get(1).isActive() +"" );
        }
    });

    holder.button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Button im = (Button) v;
            listClass task = (listClass) im.getTag(R.id.delBut);
            arr.remove(task);
            Log.e("Del but",position + "");
            Toast.makeText(getContext(),"Del",Toast.LENGTH_LONG).show();
        }
    });
    Log.e("isActive Task1", arr.get(1).isActive() +"" );
    return convertView;

}
}

ViewHolder类

public class ViewHolder {
TextView textview;
Button button;
CheckBox checkBox;
}

listClass

public class listClass {

String task;
boolean active;


public listClass(String task, boolean active) {
    this.task = task;
    this.active = active;
}


public String getTask() {
    return task;
}



public void setTask(String task) {
    this.task = task;
}

public boolean isActive() {
    return active;
}

public void setActive(boolean active) {
    this.active = active;
}
}

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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"
tools:context="com.vrishankgupta.adapter.MainActivity">

<EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:hint="Enter New Task"
    android:id="@+id/etNew"
    android:textSize="24sp"
    android:layout_gravity="left"
    android:gravity="left"/>

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="right"
    android:text="ADD"
    android:id="@+id/addButn"
    android:textSize="24sp"/>

<ListView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/vishulv"
    android:layout_marginTop="94dp"
    />

</FrameLayout>

detail.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_gravity="left"
xmlns:android="http://schemas.android.com/apk/res/android">

<TextView
    android:id="@+id/todoTaskTV"
    android:layout_width="90dp"
    android:layout_height="wrap_content"
    android:layout_centerVertical="true"
    android:layout_alignParentLeft="true"
    android:paddingLeft="8dp"
    android:textSize="18sp"
    android:textStyle="bold" />

<Button
    android:id="@+id/delBut"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_centerVertical="true"
    android:text="Delete"
    android:layout_marginRight="5dp"
     />

<CheckBox
    android:id="@+id/checkBut"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_toLeftOf="@id/delBut"
    android:layout_centerVertical="true"
    android:layout_marginRight="10dp" />
</RelativeLayout>

我想删除单击删除按钮上的List元素或用checkBox切换任务状态，我甚至没有看到Checkbox和Delete Button的clickListener中出现的Toast，只是什么都没发生，无法弄明白怎么做..

Answer 1

在你的适配器中试试这个

holder.checkBox.setOnCheckedChangeListener(new OnCheckedChangeListener() {
    @Override 
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
          if (buttonView.isChecked()) { 
                //checked

           Toast.makeText(getContext(),"active checkbox",Toast.LENGTH_LONG).show();
                       } 
          else 
          {
                //not checked
          Toast.makeText(getContext(),"inactive checkbox",Toast.LENGTH_LONG).show();
          }

});

Answer 2

制作回调界面以解决您的问题。我认为这是你想达到的最佳方式。

OnItemClickListener

public class OnItemClickListener implements View.OnClickListener {
private int position;


private OnItemClickCallback onItemClickCallback;

public OnItemClickListener(int position, OnItemClickCallback 
onItemClickCallback) {
this.position = position;
this.onItemClickCallback = onItemClickCallback;
 }

  @Override
  public void onClick(View view) {
  onItemClickCallback.onItemClicked(view, position);
   }

   public interface OnItemClickCallback {
   void onItemClicked(View view, int position);

    }
 }

在您的适配器类

中

private OnItemClickListener.OnItemClickCallback onItemClickCallback;
public CustomAdapter(@NonNull Context context, ArrayList<listClass> arr, 
OnItemClickListener.OnItemClickCallback onItemClickCallback) 
{
 super(context,R.layout.detail, arr);
 this.arr = new ArrayList<listClass>(0);
 this.onItemClickCallback = onItemClickCallback;
 this.arr.addAll(arr);

   }

和

     holder.imageButton.setOnClickListener(new OnItemClickListener(position, 
     onItemClickCallback));

在您的活动中

private OnItemClickListener.OnItemClickCallback 
 onItemDeleteClickCallback = new 
  OnItemClickListener.OnItemClickCallback() {

@Override
public void onItemClicked(View view, int position) {

    //here you will get delete item pos

}
};

和

 CustomAdapter adapter = new CustomAdapter(MainActivity.this, arr, 
 onItemDeleteClickCallback );
                final ListView lv = findViewById(R.id.vishulv);
                lv.setAdapter(adapter);

希望这会对你有所帮助。

在CustomAdapter ListView中删除按钮

2 个答案: