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java 列表展开方式_android列表控件实现展开 收缩功能

时间:2020-12-28 10:09:35

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java 列表展开方式_android列表控件实现展开 收缩功能

最近在做一个Rss阅读器,我看了一看别人做的阅读器中的lisView可以伸缩,展开,我就在网上搜索了一下。果然让我找到,下面就我找到的一个小例子,给大家分享一下。

ActivityMain .java

package com.android;

import android.app.ExpandableListActivity;

import android.os.Bundle;

import android.view.ContextMenu;

import android.view.MenuItem;

import android.view.View;

import android.view.ContextMenu.ContextMenuInfo;

import android.widget.ExpandableListAdapter;

import android.widget.ExpandableListView;

import android.widget.TextView;

import android.widget.Toast;

import android.widget.ExpandableListView.ExpandableListContextMenuInfo;

public class ActivityMain extends ExpandableListActivity {

private ExpandableListAdapter mAdapter;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

this.setTitle("ExpandableList");

mAdapter = new MyExpandableListAdapter(this);

setListAdapter(mAdapter);

registerForContextMenu(this.getExpandableListView());

}

//为列表的每一项创建上下文菜单(即长按后 呼出的菜单)

@Override

public void onCreateContextMenu(ContextMenu menu, View v,

ContextMenuInfo menuInfo) {

menu.setHeaderTitle("ContexMenu");

menu.add(0,0,0,"ContextMenu");

}

//单击上下文菜单后的逻辑

@Override

public boolean onContextItemSelected(MenuItem item) {

ExpandableListContextMenuInfo info = (ExpandableListContextMenuInfo)item.getMenuInfo();

String title = ((TextView) info.targetView).getText().toString();

int type =ExpandableListView.getPackedPositionType(info.packedPosition);

if(type == ExpandableListView.PACKED_POSITION_TYPE_CHILD)

{

int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition);

int childPos = ExpandableListView.getPackedPositionChild(info.packedPosition);

Toast.makeText(this, title+"-Group Index"+groupPos+"Child Index:"+childPos,

Toast.LENGTH_SHORT).show();

return true;

}

return false;

}

MyExpandableListAdapter.java

package com.android;

import android.content.Context;

import android.view.Gravity;

import android.view.View;

import android.view.ViewGroup;

import android.widget.AbsListView;

import android.widget.BaseExpandableListAdapter;

import android.widget.TextView;

public class MyExpandableListAdapter extends BaseExpandableListAdapter {

private Context mContext;

//父列表数据

private String[] groups ={"group1","group2","group3","group4",""};

//子列表数据

private String [][] children ={

{"child1"},

{"child1","child2"},

{"child1","child2","child3"},

{"child1","child2","child3","child4"},

};

MyExpandableListAdapter(Context context){

mContext = context;

}

@Override

public Object getChild(int groupPosition, int childPosition) {

// TODO Auto-generated method stub

return children[groupPosition][childPosition];

}

@Override

public long getChildId(int groupPosition, int childPosition) {

// TODO Auto-generated method stub

return childPosition;

}

//取子列表中的某一项的view

@Override

public View getChildView(int groupPosition, int childPosition,

boolean isLastChild, View convertView, ViewGroup parent) {

TextView textView = getGenericView();;

textView.setText(getChild(groupPosition, childPosition).toString());

return textView;

}

@Override

public int getChildrenCount(int groupPosition) {

// TODO Auto-generated method stub

return children[groupPosition].length;

}

@Override

public Object getGroup(int groupPosition) {

return groups[groupPosition];

}

@Override

public int getGroupCount() {

// TODO Auto-generated method stub

return groups.length;

}

@Override

public long getGroupId(int groupPosition) {

// TODO Auto-generated method stub

return groupPosition;

}

@Override

public View getGroupView(int groupPosition, boolean isExpanded,

View convertView, ViewGroup parent) {

TextView textView = getGenericView();

textView.setText(getGroup(groupPosition).toString());

return textView;

}

@Override

public boolean hasStableIds() {

// TODO Auto-generated method stub

return true;

}

@Override

public boolean isChildSelectable(int groupPosition, int childPosition) {

// TODO Auto-generated method stub

return true;

}

//获取某一项的view的逻辑

private TextView getGenericView(){

AbsListView.LayoutParams lp = new AbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,48);

TextView textView = new TextView(mContext);

textView.setLayoutParams(lp);

textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);

textView.setPadding(32, 0, 0, 0);

return textView;

}

}

运行的结果如下:

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。

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