Android ListView使用

最新推荐文章于 2024-05-05 09:36:01 发布

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本文详细介绍了如何在Android应用中创建自定义Adapter以配合ListView使用，包括Adapter的定义、ListView的布局设置及滑动事件监听的实现。

定义Adapter

package com.example.administrator.myapplication;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import android.widget.Toast;

import java.util.List;

/**
 * Created by Administrator on 2019/1/27 0027.
 */

public class ViewHolderAdapter extends BaseAdapter {

    List<String> mData;

    public ViewHolderAdapter(List<String> mData) {
        this.mData = mData;
    }


    @Override
    public int getCount() {
        return mData.size();
    }

    @Override
    public Object getItem(int i) {
        return mData.get(i);
    }

    @Override
    public long getItemId(int i) {
        return i;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        ViewHolder holder;
        if(view==null){
            holder=new ViewHolder();
            view= LayoutInflater.from(viewGroup.getContext())
                    .inflate(R.layout.layout_item,null,false);
            holder.textView=view.findViewById(R.id.tv);
            view.setTag(holder);
        }else{
            holder=(ViewHolder)view.getTag();
        }
        holder.textView.setText(mData.get(i));
        holder.textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(view.getContext(),((TextView)view).getText().toString()
                        , Toast.LENGTH_SHORT).show();
            }
        });
        return view;
    }
    public final class ViewHolder{
        public TextView textView;
    }
}

定义ListView 对应的布局，并设置空数据要显示的默认控件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <ListView
        android:id="@+id/lv_list"
        android:divider="@color/colorPrimary"
        android:dividerHeight="2px"
        android:scrollbars="none"
        android:listSelector="@color/colorAccent"
        android:layout_width="match_parent"
        android:layout_weight="1"
        android:layout_height="0dp"
        />
    <ImageView
        android:layout_weight="1"
        android:id="@+id/im"
        android:src="@mipmap/ic_launcher"
        android:layout_width="match_parent"
        android:layout_height="0dp" />
    <Button
        android:text="test"
        android:id="@+id/btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

package com.example.administrator.myapplication;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.support.annotation.Nullable;
import android.util.Log;
import android.view.View;
import android.widget.AbsListView;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by Administrator on 2019/1/27 0027.
 */

public class ListViewActivity extends Activity {
    private ListView listView;
    private List<String> mData=new ArrayList<>();
    private ViewHolderAdapter aDataAdapter;
    private Handler handler;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.layout_listview);
        listView=findViewById(R.id.lv_list);
        for (int i=0;i<20;i++){
            mData.add("Test "+i);
        }
        aDataAdapter=new ViewHolderAdapter(mData);
        listView.setAdapter(aDataAdapter);
        //listView.setSelection(5);
        listView.smoothScrollToPosition(14);
        handler=new Handler();
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                for (int i=0;i<10;i++){
                    mData.add("Test "+19+i);
                }
                aDataAdapter.notifyDataSetChanged();
            }
        },2000);
        listView.setEmptyView(findViewById(R.id.im));
    }

    @Override
    protected void onResume() {
        super.onResume();
        Button btn=findViewById(R.id.btn);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int count =listView.getCount();
                Toast.makeText(ListViewActivity.this,
                        " count "+count, Toast.LENGTH_SHORT).show();
                mData.clear();
                aDataAdapter.notifyDataSetChanged();
            }
        });
        listView.setOnScrollListener(new AbsListView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(AbsListView absListView, int i) {

            }

            @Override
            public void onScroll(AbsListView absListView, int firstVisibleItem
                    , int visibleItemCount, int totalItemCount) {
                if(absListView.getCount()>0&&
                        (firstVisibleItem+visibleItemCount)==absListView.getCount()
                        &&!mData.contains("this is last one")){
                        mData.add("this is last one");
                        aDataAdapter.notifyDataSetChanged();
                }
            }
        });
    }
}

滑动事件的监听