又好幾天沒有寫博客了晨另,上周末出去玩了一趟兜叨,昨天下班回來又和基友打了一晚上LOL穿扳,一晃幾天就過去了衩侥,現(xiàn)在心里又有了快畢業(yè)時回想虛度學(xué)校生活的罪惡感,今天再也不能玩了矛物,開擼吧茫死。
不知道大家有沒有遇到過在ListView中使用CheckBox之類的控件,相信這類需求還是很常見的履羞,這里面也有一個很常見的問題峦萎,如果我們不對CheckBox這樣的控件做特殊處理的話,ListView的OnItemClick事件就不會觸發(fā)忆首,其實原因很簡單爱榔,是因為CheckBox的焦點優(yōu)先級比ListView要高,我們點擊Item的時候糙及,焦點會被CheckBox搶占详幽,然后會觸發(fā)CheckBox的點擊事件,類似的控件還有Button,RadioButton浸锨,其實解決起來也不是很難唇聘,只需要在xml中給這些控件設(shè)置兩個屬性就可以了(java代碼中設(shè)置無效):
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="40dp"
android:padding="5dp">
<TextView
android:id="@+id/content"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:gravity="center_vertical"
android:padding="5dp"
/>
<CheckBox
android:id="@+id/choose"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:focusable="false"
android:focusableInTouchMode="false"
/>
</LinearLayout>
以下是Activty中代碼:
package com.meskal.test;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends Activity implements View.OnClickListener {
private Button btnAll,btnNone;
private ListView lv;
private DataAdapter mAdapter;
private List<Data> list;
@Override protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
setListener();
initData();
}
private void initView() {
btnAll = (Button) findViewById(R.id.all);
btnNone = (Button) findViewById(R.id.none);
lv = (ListView) findViewById(R.id.list);
}
private void setListener() {
btnAll.setOnClickListener(this);
btnNone.setOnClickListener(this);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Data data = list.get(position);
data.setSelected(!data.isSelected());
mAdapter.setData(list);
}
});
}
private void initData() {
mAdapter = new DataAdapter(this);
lv.setAdapter(mAdapter);
list = new ArrayList<>();
for (int i = 0; i <30; i++) {
list.add(new Data("這是第" + i+ "條內(nèi)容", false));
}
mAdapter.setData(list);
}
@Override public void onClick(View v) {
switch (v.getId()){
case R.id.all:
for (Data data : list){
data.setSelected(true);
}
mAdapter.setData(list);
break;
case R.id.none:
for (Data data : list){
data.setSelected(false);
}
mAdapter.setData(list);
break;
}
}
}
主頁布局很簡單,這里面用一個ScrollView嵌套ListView,一般會出現(xiàn)可能只顯示一行數(shù)據(jù)柱搜,其他的要滑動才能看到迟郎,這里可以自定義計算一下ListView的高度然后重新設(shè)置param:
public static void setListViewHeightBasedOnChildren(ListView listView) {
ListAdapter listAdapter = listView.getAdapter();
if (listAdapter == null) {
// pre-condition
return;
}
int totalHeight = listView.getPaddingTop() + listView.getPaddingBottom();
for (int i = 0; i < listAdapter.getCount(); i++) {
View listItem = listAdapter.getView(i, null, listView);
if (listItem instanceof ViewGroup) {
listItem.setLayoutParams(
new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
}
listItem.measure(0, 0);
totalHeight += listItem.getMeasuredHeight();
}
ViewGroup.LayoutParams params = listView.getLayoutParams();
params.height = totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1));
listView.setLayoutParams(params);
}
這方法依次計算每個Item高度然后累加起來然后再設(shè)置ListView的高度,相對來說比較繁瑣冯凹,當(dāng)然還有更簡單的方法谎亩,只需要在布局文件中設(shè)置ScrollView的一個屬性就可以了:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<ScrollView
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:fillViewport="true"
>
<ListView
android:id="@+id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:divider="@drawable/line"
android:dividerHeight="1px"
android:listSelector="@android:color/transparent"
android:cacheColorHint="@android:color/transparent"
/>
</ScrollView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="40dp"
android:orientation="horizontal"
>
<Button
android:id="@+id/all"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="全選"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:background="@drawable/btn_bg"
/>
<Button
android:id="@+id/none"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="全不選"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:background="@drawable/btn_bg"
/>
</LinearLayout>
</LinearLayout>
在pojo里面,我們加一個屬性標注該對象是否被選中,當(dāng)然也可以用一個map來記錄每個Item是否被選中宇姚,可以以位置為key,是否選中為value浑劳,但是如果我們還要在別的地方獲取某條數(shù)據(jù)的狀態(tài)還是下面這種更好用:
package com.meskal.test;
public class Data {
private String content;
private boolean isSelected;
public Data(String s, boolean b) {
this.content = s;
this.isSelected = b;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
public boolean isSelected() {
return isSelected;
}
public void setSelected(boolean selected) {
isSelected = selected;
}
}
adapter中內(nèi)容很常見了阱持,相信大家都寫過N遍了,最近RecycleView很流行魔熏,用了一次衷咽,感覺比ListView靈活多了,表格蒜绽,瀑布流效果美爆了镶骗,以后要多用用那個了,ListView相對簡單多了:
package com.meskal.test;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.CheckBox;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Created by 25711 on 2016/8/9.
* Function:
* Version:
*/
public class DataAdapter extends BaseAdapter{
private Context mContext;
private LayoutInflater inflater;
private List<Data> datas;
public DataAdapter(Context context){
this.mContext = context;
inflater = LayoutInflater.from(context);
datas = new ArrayList<>();
}
public void setData(List<Data> list){
if (list == null){
return;
}
this.datas = list;
notifyDataSetChanged();
}
@Override public int getCount() {
return datas.size();
}
@Override public Object getItem(int position) {
return datas.get(position);
}
@Override public long getItemId(int position) {
return position;
}
@Override public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if(convertView == null){
holder = new ViewHolder();
convertView = inflater.inflate(R.layout.list_item, parent, false);
holder.tv = (TextView) convertView.findViewById(R.id.content);
holder.cb = (CheckBox) convertView.findViewById(R.id.choose);
convertView.setTag(holder);
}else {
holder = (ViewHolder) convertView.getTag();
}
holder.tv.setText(datas.get(position).getContent());
holder.cb.setChecked(datas.get(position).isSelected());
return convertView;
}
private static class ViewHolder{
TextView tv;
CheckBox cb;
}
}
整體來說只是很簡單的兩個知識點躲雅,一個是設(shè)置焦點優(yōu)先級高的控件不可獲的焦點鼎姊,防止其搶占ListView的焦點,還一個就是ScrollView嵌套ListView等這樣的滑動控件時讓其撐滿整個空間使用android:fillViewport="true",以及通過代碼設(shè)置Listview的高度方法