Andriod开发 ListView

1.ListView

列表视图，用于展示数据列表，比如帖子列表，商品列表，一般和Adapter一起使用

例子是一个简单的ListView

package com.example.chapter08;

import androidx.appcompat.app.AppCompatActivity;

import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.Toast;

import com.example.chapter08.entity.Planet;

import java.util.List;

public class ListViewActivity extends AppCompatActivity implements AdapterView.OnItemClickListener, CompoundButton.OnCheckedChangeListener {

    private List<Planet> list;
    private ListView lv;
    private CheckBox cb_divider;
    private CheckBox cb_selector;

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

        lv = findViewById(R.id.lv);


        list = Planet.getDefaultList();
        PlanetBaseAdapter baseAdapter = new PlanetBaseAdapter(this, list);
        lv.setAdapter(baseAdapter);
        lv.setOnItemClickListener(this);

        cb_divider = findViewById(R.id.cb_divider);
        cb_selector = findViewById(R.id.cb_selector);

        cb_divider.setOnCheckedChangeListener(this);
        cb_selector.setOnCheckedChangeListener(this);

    }

    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
        Toast.makeText(this,"You select " + list.get(i).name, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
        switch (compoundButton.getId()){
            case R.id.cb_divider:
                if(cb_divider.isChecked()){
                    Drawable divider = getResources().getDrawable(R.color.black, getTheme());
                    lv.setDivider(divider);
                    lv.setDividerHeight(1);
                }else{
                    lv.setDivider(null);
                    lv.setDividerHeight(0);
                }

                break;
            case R.id.cb_selector:
                if(cb_selector.isChecked()){
                    lv.setSelector(R.drawable.list);
                }else{
                    Drawable drawable = getResources().getDrawable(R.color.transparent);
                    lv.setSelector(drawable);
                }
                break;
        }
    }
}

<?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=".ListViewActivity">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="70dp">
        <CheckBox
            android:id="@+id/cb_divider"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:text="divider"
            android:textSize="30dp"
            android:layout_height="match_parent"></CheckBox>

        <CheckBox
            android:id="@+id/cb_selector"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="match_parent"
            android:text="selector"
            android:textSize="30dp"
            ></CheckBox>


    </LinearLayout>

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

</LinearLayout>

 2.ListView点击事件冲突

当item里面放置一个button后，设置监听button，会发现button可以正常点击，但是点击item（非button部分）时，会没有响应。

这是因为ListView默认会把焦点传递给子项，可以之间在item的布局中设置

android:descendantFocusability="blocksDescendants"

这样item就会得到焦点，响应用户点击