BaseAdapter

秒速五厘米 2022-06-05 00:52 201阅读 0赞

这是一个使用BaseAdapter编程的实例。

## 源代码 ##

### MainActivity ###

package com.example.administrator.listview;
    
    import android.content.Intent;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.SimpleAdapter;
    
    public class MainActivity extends AppCompatActivity implements View.OnClickListener { 
    
        //设置3个按钮
        Button btnArray, btnSimple, btnBase;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            //找到xml中的按钮
            btnArray = ((Button) findViewById(R.id.array_adapter));
            btnSimple = ((Button) findViewById(R.id.simple_adapter));
            btnBase = ((Button) findViewById(R.id.base_adapter));
    
            //设置监听事件
            btnArray.setOnClickListener(this);
            btnSimple.setOnClickListener(this);
            btnBase.setOnClickListener(this);
        }
    
        @Override
        public void onClick(View v) {
    
            switch (v.getId()) {
    
                //按下第一个按钮的情况
                case R.id.array_adapter:
    
                    Intent intent = new Intent(this, ArrayActivity.class);
                    startActivity(intent);
    
                    break;
    
                //按下第二个按钮的情况
                case R.id.simple_adapter:
    
                    Intent simpleIntent = new Intent(this,SimpleActivity.class);
                    startActivity(simpleIntent);
    
                    break;
    
                //按下第三个按钮的情况
                case R.id.base_adapter:
    
                    Intent baseIntent = new Intent(this,BaseActivity.class);
                    startActivity(baseIntent);
    
                    break;
    
            }
    
        }
    }

### activity\_main ###

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout 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" android:orientation="vertical" tools:context="com.example.administrator.listview.MainActivity">
    
        <Button android:id="@+id/array_adapter" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="ArrayAdapt" />
    
        <Button android:id="@+id/simple_adapter" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="SimpleAdapt" />
    
        <Button android:id="@+id/base_adapter" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="BaseAdapt" />
    
    </LinearLayout>

### BaseActivity ###

package com.example.administrator.listview;
    
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.AdapterView;
    import android.widget.BaseAdapter;
    import android.widget.ListView;
    import android.widget.TextView;
    import android.widget.Toast;
    
    import java.util.ArrayList;
    import java.util.List;
    
    public class BaseActivity extends AppCompatActivity { 
    
        ListView listView;
    
        List<User> data;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_base);
    
            listView = ((ListView) findViewById(R.id.listview));
    
            data = new ArrayList<>();
    
            data.add(new User("john", 21));
            data.add(new User("john2", 22));
            data.add(new User("john3", 23));
            data.add(new User("john4", 25));
            data.add(new User("john5", 27));
            data.add(new User("john6", 28));
            data.add(new User("john7", 28));
            data.add(new User("john8", 28));
            data.add(new User("john9", 20));
            data.add(new User("john10", 28));
            data.add(new User("john11", 29));
    
            MyApdater myadpater = new MyApdater();
    
            listView.setAdapter(myadpater);
    
            listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    
                    User user = data.get(position);
    
                    Toast.makeText(getApplicationContext(),user.getName()+" "+user.getAge(),Toast.LENGTH_LONG).show();
                }
            });
    
    
        }
    
        class MyApdater extends BaseAdapter {
    
            @Override
            public int getCount() {
                return data.size();
            }
    
            @Override
            public Object getItem(int position) {
                return data.get(position);
            }
    
            @Override
            public long getItemId(int position) {
                return position;
            }
    
    
            //这个方法在安卓绘制listview的每一项的时候都会调用
            @Override
            public View getView(int position, View convertView, ViewGroup parent) {
    
                ViewHolder holder;
    
                if (convertView == null) {
    
                    holder = new ViewHolder();
    
                    convertView = LayoutInflater.from(getApplication()).inflate(R.layout.base_item, null);
    
                    holder.tvName = ((TextView) convertView.findViewById(R.id.base_item_name));
    
                    holder.tvAge = ((TextView) convertView.findViewById(R.id.base_item_age));
    
                    convertView.setTag(holder);
    
                } else
    
                {
                    holder = ((ViewHolder) convertView.getTag());
                }
    
    
                User user = data.get(position);
    
                holder.tvName.setText(user.getName());
    
                holder.tvAge.setText(user.getAge() + " ");
    
                return convertView;
            }
    
            class ViewHolder {
    
                TextView tvName;
                TextView tvAge;
    
    
            }
    
        }
    
    
    }

### activity\_base ###

<?xml version="1.0" encoding="utf-8"?>
    <ListView 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:id="@id/listview" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.administrator.listview.BaseActivity">
    
    </ListView>