ScrollView嵌套ListView——求解listView的高度

最新推荐文章于 2018-01-27 23:13:33 发布

原创最新推荐文章于 2018-01-27 23:13:33 发布 · 608 阅读

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布局中的实现代码

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.scrollview.MainActivity" >
    <LinearLayout 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        >
        <com.example.utils.MyListView
            android:id="@+id/lv"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            ></com.example.utils.MyListView>
    </LinearLayout>
</ScrollView>

1：自定义的类型
//上面listView的控件我们使用的是自定义的listView
自定义的控件在布局中引用就能实现展开listview

import android.content.Context;
import android.util.AttributeSet;
import android.widget.ListView;
public class MyListView extends ListView {

    public MyListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public MyListView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyListView(Context context) {
        super(context);
    }
    //设置ListView展示高度
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int measureSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE>>2, MeasureSpec.AT_MOST);
        super.onMeasure(widthMeasureSpec, measureSpec);
    }
}

主方法中的实现代码

import java.util.ArrayList;
import java.util.List;
import com.example.adapter.MyBaseAdapter;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.ListView;

public class MainActivity extends Activity {
    //定义控件
    private ListView lv;
    //定义一个集合保存数据
    private List<String> list=new ArrayList<String>();
    //定义适配器
    private MyBaseAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获得控件的id 
        lv=(ListView) findViewById(R.id.lv);
        for (int i = 0; i < 50; i++) {
            list.add("button"+i);
        }
        adapter=new MyBaseAdapter(MainActivity.this, list);
        lv.setAdapter(adapter);
    }
}

2：计算的类型
就是获得适配器获得item项的个数求高度布局同上主方法中的实现代码

import java.util.ArrayList;
import java.util.List;
import com.example.adapter.MyBaseAdapter;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListAdapter;
import android.widget.ListView;

public class MainActivity extends Activity {
    //定义控件
    private ListView lv;
    //定义一个集合保存数据
    private List<String> list=new ArrayList<String>();
    //定义适配器
    private MyBaseAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获得控件的id 
        lv=(ListView) findViewById(R.id.lv);
        for (int i = 0; i < 50; i++) {
            list.add("button"+i);
        }
        adapter=new MyBaseAdapter(MainActivity.this, list);
        lv.setAdapter(adapter);
        //计算一下listView的高度
        setListViewHeight(lv);


    }
    @SuppressWarnings("unused")
    private void setListViewHeight(ListView mListView2) {
        ListAdapter listAdapter=mListView2.getAdapter();
        int count=listAdapter.getCount();
        int heightall=0;
        for (int i = 0; i < count; i++) {
            View view=listAdapter.getView(i, null, mListView2);
            view.measure(0, 0);
            heightall+=view.getMeasuredHeight();
            heightall+=mListView2.getDividerHeight();
        }
        heightall-=mListView2.getDividerHeight();
        //把得到的高度设置给 v`
        ViewGroup.LayoutParams layoutParams=mListView2.getLayoutParams();
        layoutParams.height=heightall;
    }
}

3：计算的util引用包类型

import android.view.View;
import android.view.ViewGroup;
import android.widget.ListAdapter;
import android.widget.ListView;
/**
 * 与所有布局有关的工具类
 * @author Administrator
 *
 */
public class ViewUtil {

    public static void setListViewHeightBasedOnChildren(ListView listView) {
        ListAdapter listAdapter = listView.getAdapter();
        if (listAdapter == null) {
          return;
        }
        int totalHeight = 0;
        for (int i = 0; i < listAdapter.getCount(); i++) {
          View listItem = listAdapter.getView(i, null, listView);
          listItem.measure(0, 0);
          totalHeight += listItem.getMeasuredHeight();
        }

        ViewGroup.LayoutParams params = listView.getLayoutParams();
        params.height = totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1));
        listView.setLayoutParams(params);
    }





    /**
     * 设置listview的高度
     * @param listView
     * @return 
     */
    public static int setListViewHeightBasedOnChildren1(ListView listView) {
        //获取ListView对应的Adapter
        ListAdapter listAdapter = listView.getAdapter();
        if (listAdapter == null) {
          // pre-condition
          return 0;
        }

        int totalHeight = 0;
        for (int i = 0, len = listAdapter.getCount(); i < len; i++) { //listAdapter.getCount()返回数据项的数目
          View listItem = listAdapter.getView(i, null, listView);
          listItem.measure(0, 0); //计算子项View 的宽高
          totalHeight += listItem.getMeasuredHeight(); //统计所有子项的总高度
        }
        ViewGroup.LayoutParams params = listView.getLayoutParams();
        params.height = totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1));
        //listView.getDividerHeight()获取子项间分隔符占用的高度
        //params.height最后得到整个ListView完整显示需要的高度
        listView.setLayoutParams(params);
        return params.height;
      }
}

//主类中的实现代码

import java.util.ArrayList;
import java.util.List;
import com.example.adapter.MyBaseAdapter;
import com.example.utils.ViewUtil;
import android.app.Activity;
import android.os.Bundle;
import android.view.ViewGroup;
import android.widget.ListView;

public class MainActivity extends Activity {
    //定义控件
    private ListView lv;
    //定义一个集合保存数据
    private List<String> list=new ArrayList<String>();
    //定义适配器
    private MyBaseAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获得控件的id 
        lv=(ListView) findViewById(R.id.lv);
        for (int i = 0; i < 50; i++) {
            list.add("button"+i);
        }
        adapter=new MyBaseAdapter(MainActivity.this, list);
        lv.setAdapter(adapter);     
        //计算一下listView的高度
        int listViewHeight = ViewUtil.setListViewHeightBasedOnChildren1(lv);
        ViewGroup.LayoutParams params = lv.getLayoutParams();
        params.height = listViewHeight;
        lv.setLayoutParams(params);     
    }   
}