Android学习-ListView再视

之前接触了一点ListView的基础知识，但没有自己去敲，学的不是很深刻，今天我按照教程，写了一个listview的基本实现，基本掌握了listview

listview的学习是为了给RecyclerView打一下基础，毕竟RecyclerView优点更多，更好用，实际开发中主要就是用到它。

先看看实现了什么效果：首先我为了省事，直接把每一个单元内的内容设置的一样，之后实际使用的时候肯定不这么弄了~

然后就是可以上下滑动，点击第几个就会弹出：  “点击pos:几”  的效果，在实际使用中，我们可以将这个效果改为跳转到对应的界面。

 代码实现，先放最主要的部分

MyListAdapter.java

package com.example.testapplication.listview;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

import com.example.testapplication.R;

public class MyListAdapter extends BaseAdapter {

    private Context mContext;
    private LayoutInflater mLayoutInflater;
    public MyListAdapter(Context context){
        this.mContext = context;
        mLayoutInflater = LayoutInflater.from(context);
    }
    @Override
    public int getCount() {
        return 10;
    }

    @Override
    public Object getItem(int i) {
        return null;
    }

    @Override
    public long getItemId(int i) {
        return 0;
    }

    static class ViewHolder{
        public TextView tv1,tv2,tv3;
    }
    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        ViewHolder holder = null;
        if (view == null){
            view = mLayoutInflater.inflate(R.layout.layout_list_item,null);
            holder = new ViewHolder();

            holder.tv1=(TextView) view.findViewById(R.id.tv_1);
            holder.tv2=(TextView) view.findViewById(R.id.tv_2);
            holder.tv3=(TextView) view.findViewById(R.id.tv_3);

            view.setTag(holder);
        }else{
            holder = (ViewHolder) view.getTag();
        }
        //给控件赋值
        holder.tv1.setText("姓名是");
        holder.tv2.setText("班级是");
        holder.tv3.setText("学号是");

        return view;
    }
}

ListViewActivity.java

package com.example.testapplication.listview;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;

import com.example.testapplication.R;

public class ListViewActivity extends AppCompatActivity {

    private ListView mLv1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_list_view);

        mLv1 = (ListView) findViewById(R.id.lv_1);
        mLv1.setAdapter(new MyListAdapter(ListViewActivity.this));
        mLv1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Toast.makeText(ListViewActivity.this, "点击pos:"+position, Toast.LENGTH_SHORT).show();
            }
        });
    }
}

MainActivity.java

package com.example.testapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import com.example.testapplication.listview.ListViewActivity;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    private Button btn_listview;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        btn_listview = (Button) findViewById(R.id.btn_listview);
        btn_listview.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        if (findViewById(R.id.btn_listview).equals(view)) {
            Intent intent = new Intent(this, ListViewActivity.class);
            startActivity(intent);
        }

    }

}