[英]Different select colors for different list view items
我有以下要求:
无论出于何种原因,它似乎都没有像我想象的那样直截了当。 唯一能够朝着正确方向发展的解决方案是: https : //stackoverflow.com/a/16978159/658718
需要注意的是,这不会更改选择颜色,但会永久更改背景颜色,如果向下滚动,它已经更改了列表视图项的背景颜色。
我怎么处理这个?
我会说具有状态意识的drawables 。 为您想要单个ListView背景的每种颜色创建一个状态感知的可绘制XML文件。 以下是一个名为background_black.xml和background_green.xml的状态感知Drawable的示例。 它们使您的默认背景颜色为白色,而按下/选择时会暂时将其更改为黑色或绿色。 这两个文件都放在Drawable文件夹中。
background_black.xml
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_window_focused="false" android:drawable="@android:color/white" />
<item android:state_pressed="true" android:color="@android:color/black" />
<item android:state_selected="true" android:color="@android:color/black" />
</selector>
background_green.xml
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_window_focused="false" android:drawable="@android:color/white" />
<item android:state_pressed="true" android:color="@android:color/green" />
<item android:state_selected="true" android:color="@android:color/green" />
</selector>
在ListView项目xml文件中,为根布局或任何提供可见背景颜色的元素指定ID。 对于此示例,Ill假设它是您的根布局。 然后在您的Adapter的getView()中,抓取您已分配id的元素,并使用您想要的背景颜色设置您创建的一个drawable。 像这样:
@Override
public View getView(int position, View convertView, ViewGroup parent){
//inflate your convertView, etc...
...
ViewGroup baseLayout = (ViewGroup)convertView.findViewById(R.id.<your base layout id>);
//these conditions need to reflect how you decide which list item gets which color
if(position % 2 == 0){
baseLayout.setBackground(R.drawable.background_black);
} else {
baseLayout.setBackground(R.drawable.background_green);
//do whatever else you need
...
return convertView;
}
注意:setBackground()是一个新函数,如果编码旧版Android,请使用setBackgroundDrawable()
这里的困难是按下/检查的颜色是动态的。 您不能使用静态xml color-state-list。 但您可以通过代码创建ColorStateList 。 这是怎么做的。
您只需要实现ListAdapter:
private class MyListAdapter implements ListAdapter{
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if(convertView!=null){
CheckedTextView textView = (CheckedTextView)convertView;
textView.setText("the text for item "+position);
textView.setTextColor(makeColorStateListForItem(position));
return textView;
}else{
CheckedTextView textView = new CheckedTextView(parent.getContext());
textView.setText("the text for item "+position);
textView.setTextColor(makeColorStateListForItem(position));
return textView;
}
}
private ColorStateList makeColorStateListForItem(int position){
int pressedColor = pressedColorForItem(position);
int checkedColor = checkedColorForItem(position);
int defaultColor = defaultColorForItem(position);
ColorStateList colorStateList = new ColorStateList(
new int[][]{
new int[]{android.R.attr.state_pressed},
new int[]{android.R.attr.state_checked},
new int[]{0},
},
new int[]{
pressedColor, //use when state is pressed
checkedColor, //use when state is checked, but not pressed
defaultColor}); //used when state is not pressed, nor checked
}
private int pressedColorForItem(int position){
//write your business logic to determine color here
return ...;
}
private int checkedColorForItem(int position){
//write your business logic to determine color here
return ...;
}
private int defaultColorForItem(int position){
return Color.WHITE;
}
//all other adapter methods
//...
注意使用android.R.attr.state_checked
而不是更直观的android.R.attr.state_selected
因为state_selected
不是用触摸屏非常精确地定义的(即state_selected可以在模拟器上给出预期的行为,但是在真正的设备,它可能会失败)
另一方面, state_checked
+ CheckedTextView将在模拟器和真实设备上正常工作。
只需调用List.setChoiceMode(...);
在clickListener中初始化listView和ListView.setItemChecked
时。
final ListView listView = ...
listView.setAdapter(new MyListAdapter());
listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
listView.setItemChecked(position,true);
}
});
编辑 :更改项目背景:只需创建一个StateListDrawable而不是简单的ColorStateList:
private Drawable makeBackgroungForItem(int position){
int pressedColor = pressedBackgroundColorForItem(position);
int checkedColor = checkedBackgroundColorForItem(position);
int defaultColor = defaultBackgroundColorForItem(position);
StateListDrawable stateListDrawable = new StateListDrawable();
stateListDrawable.addState(new int[]{android.R.attr.state_list_pressed}, new ColorDrawable(pressedColor));
stateListDrawable.addState(new int[]{android.R.attr.state_list_checked}, new ColorDrawable(checkedColor));
stateListDrawable.addState(new int[]{0, new ColorDrawable(defaultColor));
return stateListDrawable;
}
在getView(...)
textView.setBackground(makeBackgroungForItem(position));
我建议采用以下方法:
ListView
Adapter
ListItem
都有自己的.xml布局文件,因此您可以在那里指定所需的选择器 你需要什么:
ListView
中每个项继承自的基类 ListItem
View
ListItem
类可以有一个Integer
字段mColor,它保存项表示的颜色 ListItem
类可以有一个方法来设置具有特定颜色的选择器 例:
public abstract class ListItem {
public static final int TYPE_WHATEVER_1 = 0;
public static final int TYPE_WHATEVER_2 = 1;
// and so on...
/** the total number of list-item-types */
public static final int TYPE_COUNT = typecounthere;
// if required for your implementation:
protected int mColor;
public abstract int getViewType();
public abstract View getView(LayoutInflater inflater, View convertView);
/** creates and sets the selector with your specified color */
public void setupSelectorColor() {
StateListDrawable states = new StateListDrawable();
ColorDrawable cdPressed = new ColorDrawable(mColor);
ColorDrawable cdSelected = new ColorDrawable(mColor);
ColorDrawable cdDefault = new ColorDrawable(Color.TRANSPARENT);
states.addState(new int[] {
android.R.attr.state_pressed
},
cdPressed);
states.addState(new int[] {
android.R.attr.state_selected
},
cdSelected);
states.addState(new int[] {},
cdDefault);
setBackgroundDrawable(states);
}
}
ListItem
的子类 getView(...)
方法内部,膨胀您想要的布局 getViewType()
方法中返回正确的类型 例:
public class ItemTypeOne extends ListItem {
public ItemTypeOne(int color) {
mColor = color;
}
@Override
public int getViewType() {
// return the type
return TYPE_WHATEVER_1;
}
@Override
public View getView(LayoutInflater inflater, View convertView) {
if(convertView == null) {
// inflate the layout
convertView = inflater.inflate(R.layout.item_type_one, null);
}
// setup the selector
setupSelectorColor();
// do other stuff
return convertView;
}
}
例:
public class ListItemAdapter extends ArrayAdapter<ListItem> {
public ListItemAdapter(Context context, List<ListItem> objects) {
super(context, 0, objects);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
return getItem(position).getView(LayoutInflater.from(getContext()), convertView);
}
@Override
public int getItemViewType(int position) {
return getItem(position).getViewType();
}
@Override
public int getViewTypeCount() {
return ListItem.TYPE_COUNT;
}
}
把它们放在一起:
ArrayList<ListItem> list = new ArrayList<ListItem>();
// fill the list
list.add(new ItemTypeOne(somecolor));
list.add(new ItemTypeTwo(somecolor));
list.add(new ItemTypeOne(somecolor));
list.add(new ItemTypeWhatever(somecolor));
ListView lv = (ListView) v.findViewById(R.id.listView1);
ListItemAdapter a = new ListItemAdapter(Context, list);
lv.setAdapter(a);
关于CustomViews
和选择器及其行为 ,我建议阅读这个问题(和答案): 如何使用自定义选择器状态实现CustomView?
我想说不要过于复杂。 它可以很简单,因为创建一个包含可能颜色的int
数组,并使用Random
类将它们设置为每个项目。
// This goes inside hosting fragment or activity
listview.setOnItemClickListner( new OnItemClickListener() {
@Override
public void onItemClick(AdapterView parent, View view, int position, long id) {
if(view.isSelected()){
view.setSelected(false);
// also maybe change bg color back to normal?
}
else {
// This one for always a different color
view.setBackgroundColor(adapter.getColor());
// This is for foreground color change instead of background
FrameLayout frameLayout = (FrameLayout) view.findViewById(R.id.my_frame_layout);
final Drawable drawable = new ColorDrawable( /* your getColor() function */ );
frameLayout.setForeground(drawable);
// This one for alwyas the same color for the row at position given by {@param position}
view.setBackgroundColor(adapter.getColor(position));
view.setSelected(true);
}
}
});
// All this goes inside your custom listview Adapter
int[] colors = {
R.colors.red,
R.colors.blue,
...
}
Random random = new Random();
// If each time the selection will bring a different color, use this implementation
public int getColor() {
return colors[random.nextInt(colors.length)];
}
// If each row should have different color, but always the same color for a row then use this one instead
SparseIntArray spa = new SparseIntArray();
public int getColor(int position) {
if(spa.get(position) == 0) {
// the color hasnt been created for that row yet
spa.put(position, colors[random.nextInt(colors.length)];
}
return spa.get(position);
}
**编辑:**现在,如果您想要的是前景选择,那么您的行应该有一个FrameLayout
容器,您应该更改它的'android:foreground'属性:
final Drawable drawable = new ColorDrawable( /* your getColor() function */ );
frameLayout.setForeground(drawable);
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