Android学习-列表视图ListView

来源：cnblogs　　作者：YouChaoMin　　时间：2018/11/28 9:45:51　　对本文有异议

一、简介：

ListView，列表视图，直接继承了AbsListView，是一个以垂直方式在项目中显示View视图的列表。ListView的数据项，来自一个继承了ListAdapter接口的适配器。

二、新建一个包listview并新建ListViewActivity.java活动：

public class ListViewActivity extends AppCompatActivity {

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

三、在AndroidManifest.xml中声名activity：

1	<activity android:name=".listview.ListViewActivity"></activity>

四、建立activity_list_view.xml布局：

<?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">

</LinearLayout>

五、在activity_main.xml中新建一个按钮：

<Button
        android:id="@+id/btn_listview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="ListView"
        android:textAllCaps="false"/>

六、在MainActivity.java中声名控件：

1	private Button mBtnListView;

七、在MainActivity.java中找到控件：

1	mBtnListView=findViewById(R.id.btn_listview);

八、设置点击事件：

mBtnListView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //跳转到ListView演示页面
                Intent intent=new Intent(MainActivity.this,ListViewActivity.class);
                startActivity(intent);
            }
        });

九、在activity_list_view.xml布局中写代码：

<?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">

    <ListView
        android:id="@+id/lv_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

    </ListView>
</LinearLayout>

十、新建layout_list_item.xml:

<?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="horizontal"
    android:paddingLeft="15dp"
    android:paddingRight="15dp"
    android:paddingTop="10dp"
    android:paddingBottom="10dp">

    <ImageView
        android:id="@+id/iv"
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:scaleType="centerCrop"
        android:background="#000"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:paddingLeft="10dp">

        <TextView
            android:id="@+id/tv_title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello"
            android:textSize="20sp"
            android:textColor="#000"/>

        <TextView
            android:id="@+id/tv_time"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="2018-11-27"
            android:textSize="18sp"
            android:textColor="#808080"
            android:layout_marginTop="10dp"/>

        <TextView
            android:id="@+id/tv_content"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="这是内容"
            android:textSize="18sp"
            android:textColor="#808080"
            android:layout_marginTop="10dp"/>

    </LinearLayout>
</LinearLayout>

十一、在包listview中新建MyListAdapter.java继承自BaseAdapter:

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 ImageView imageView;
        public TextView tvTitle,tvTime,tvContent;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder=null;
        if(convertView==null){
            convertView=mLayoutInflater.inflate(R.layout.layout_list_item,null);
            holder=new ViewHolder();
            holder.imageView=convertView.findViewById(R.id.iv);
            holder.tvTitle=convertView.findViewById(R.id.tv_title);
            holder.tvTime=convertView.findViewById(R.id.tv_time);
            holder.tvContent=convertView.findViewById(R.id.tv_content);
            convertView.setTag(holder);
        }else{
            holder=(ViewHolder)convertView.getTag();
        }
        //给控件赋值
        holder.tvTitle.setText("这是标题");
        holder.tvTime.setText("2018-11-28");
        holder.tvContent.setText("这是内容");
        Glide.with(mContext).load("https://www.baidu.com/img/bd_logo1.png?where=super").into(holder.imageView);
        return convertView;
    }
}

十二、在ListViewActivity.java中写代码：


public class ListViewActivity extends AppCompatActivity {

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

        mLv1=findViewById(R.id.lv_1);
        mLv1.setAdapter(new MyListAdapter(ListViewActivity.this));
    }
}

运行结果：

十三、在drawable下新建一个list_item:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_selected="true" android:drawable="@color/colorAccent"/>
    <item android:state_pressed="true" android:drawable="@color/colorAccent"/>
    <item android:state_focused="true" android:drawable="@color/colorAccent"/>
    <item android:drawable="@color/colorWhite"/>
</selector>

十四、在activity_list_view.xml下配置：

<?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">

    <ListView
        android:id="@+id/lv_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:listSelector="@drawable/list_item">

    </ListView>
</LinearLayout>

运行截图：

十五、在ListViewActivity.java设置点击和长按事件：

mLv1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
         @Override
         public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
             Toast.makeText(ListViewActivity.this,"点击 pos:"+position,Toast.LENGTH_SHORT).show();
         }
     });

     mLv1.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
         @Override
         public boolean onItemLongClick(AdapterView<?> adapterView, View view, int position, long l) {
             Toast.makeText(ListViewActivity.this,"长按 pos:"+position,Toast.LENGTH_SHORT).show();
             return true;//松开后不会显示点击事件
         }
     });