[Android Pro] listView和GridView的item设置的高度和宽度不起作用

referece to : http://blog.csdn.net/beibeixiao/article/details/9032569

1. 在Android开发中会发现，有时listView和GridView的item顶层布局不起作用，即不能设置高度和宽度

原因是当用自定义的adapter时，如果使用convertView= mInflater.inflate(R.layout.material_grid_item, null)

方法就不会起作用，这个方法的第二个参数是父View，传入为空，所以没有加载顶层布局，此时如果使用

convertView= mInflater.inflate(R.layout.material_grid_item, parent,false);传入parent设置的高度和宽度就会起作用了。

二、自动适配列数

转自：http://blog.csdn.net/archer_zoro/article/details/43500389

写了一个展示多张图片的gridview（几乎每个listview里面都有一个gridview）

之前用auto_fit和设置列宽来控制列数，以达到自适应的目的。

this.setNumColumns(GridView.AUTO_FIT);
this.setColumnWidth(getResources().getDimensionPixelSize(R.dimen.item_image_size));
this.setHorizontalSpacing(getResources().getDimensionPixelSize(R.dimen.item_image_spacing));
this.setVerticalSpacing(getResources().getDimensionPixelSize(R.dimen.item_image_spacing));

这样的效果就是图片宽度最小为item_image_size，会在接近这个大小的情况下，自动调整一些大小将gridview占满，间隔不变。3列。

而后来在720p以上的手机上运行时，变成了4列，但是要求是3列，于是我把列数从auto_fit改成了3，依然是上面的显示效果，

但是，在滑动listview的过程中明显比刚才卡顿了，所以有改回了auto_fit，转而把item_image_size增大了。

原理不清楚，留下这个坑待研究

转自：http://blog.csdn.net/maizangxiangwang/article/details/50913900


/**
 * 获取屏幕宽度
*/
public static int getScreenWidth(Context context) {

    WindowManager manager = (WindowManager) context

            .getSystemService(Context.WINDOW_SERVICE);

    Display display = manager.getDefaultDisplay();

    return display.getWidth();

}

public static int dipToPx(Context context, int dip) {

    if(density <= 0.0F) {
density = context.getResources().getDisplayMetrics().density;

    }

    return (int)((float)dip * density + 0.5F);

}

给gridview子项要屏幕适配，子项item宽度，高度与宽度相同

itemWidth = (getScreenWidth(this)-(3*dipToPx(this, 3)))/2;

在gridview的adapter中的getview中设置子项的参数

public View getView(int position, View convertView, ViewGroup parent) {

    ViewHodler viewHodler;

    String url = blogAlbumList.get(position).getAlbumUrl();

    if (convertView == null) {

        convertView = View.inflate(context, R.layout.celebrity_item, null);

        viewHodler = new ViewHodler();

        viewHodler.iv_image = (ImageView) convertView.findViewById(R.id.iv_image);

        convertView.setTag(viewHodler);

    } else {

        viewHodler = (ViewHodler) convertView.getTag();

    }

    // if (viewHodler.iv_image.getTag()!=url ||viewHodler.iv_image.getTag()==null) {

    ImageTools.getImageLoader().displayImage(blogAlbumList.get(position).getAlbumUrl(), viewHodler.iv_image, mDisplayImageOptions);

    // viewHodler.iv_image.setTag(url);

    // }

    AbsListView.LayoutParams param = new AbsListView.LayoutParams(LeoApplication.itemWidth, LeoApplication.itemWidth);

    convertView.setLayoutParams(param);

    return convertView;

}

其实gridview有个属性.Android:stretchMode=”columnWidth"//缩放与列宽大小同步

GridView的一些特殊属性：

1.android:numColumns=”auto_fit” //GridView的列数设置为自动

2.android:columnWidth=”90dp " //每列的宽度，也就是Item的宽度

3.android:stretchMode=”columnWidth"//缩放与列宽大小同步

4.android:verticalSpacing=”10dp” //两行之间的边距

5.android:horizontalSpacing=”10dp” //两列之间的边距

6.android:cacheColorHint="#00000000" //去除拖动时默认的黑色背景

7.android:listSelector="#00000000" //去除选中时的黄色底色

8.android:scrollbars="none" //隐藏GridView的滚动条

9.android:fadeScrollbars="true" //设置为true就可以实现滚动条的自动隐藏和显示

10.android:fastScrollEnabled="true" //GridView出现快速滚动的按钮(至少滚动4页才会显示)

11.android:fadingEdge="none" //GridView衰落(褪去)边缘颜色为空，缺省值是vertical。(可以理解为上下边缘的提示色)

12.android:fadingEdgeLength="10dip" //定义的衰落(褪去)边缘的长度

13.android:stackFromBottom="true" //设置为true时，你做好的列表就会显示你列表的最下面

14.android:transcriptMode="alwaysScroll" //当你动态添加数据时，列表将自动往下滚动最新的条目可以自动滚动到可视范围内

15.android:drawSelectorOnTop="false" //点击某条记录不放，颜色会在记录的后面成为背景色,内容的文字可见(缺省为false)

三、添加Header和Footer

转自：http://blog.csdn.net/zhzhyang0313/article/details/39163735

实现这个功能一般有两种思路，一种思路是使用ScrollView+GridView，第二种思路是使用ListView来实现GridView的效果。

第一种思路的具体实现是把HeaderView和GridView都放到ScrollView里面，这里要解决的问题是ScrollView和GridView滑动手势的冲突问题，解决办法是让GridView充满ScrollView，不让GridView滑动而只让ScrollView滑动。具题做法是重载GridView的onMeasure()方法。

public class MyGridView extends GridView {
public MyGridView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyGridView(Context context) {
super(context);
}
public MyGridView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int expandSpec = MeasureSpec.makeMeasureSpec(
Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}
}

这种方法的不足是GridView中的View没有复用，如果内容较多将比较消耗内存。

第二种思路的具体实现是使用ListView的addHeaderView()来添加HeaderView，而ListView的每一行都放一个LinearLayout来保存一行的item，这里要注意的是item的个数和ListView行数的关系。

后来在*上又看到了第三中方法。原来Google已经用GridView实现了，而且很巧妙，下面把代码贴出来

/*
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.photos.views;
import android.content.Context;
import android.database.DataSetObservable;
import android.database.DataSetObserver;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.FrameLayout;
import android.widget.GridView;
import android.widget.ListAdapter;
import android.widget.WrapperListAdapter;
import java.util.ArrayList;
/**
* A {@link GridView} that supports adding header rows in a
* very similar way to {@link ListView}.
* See {@link HeaderGridView#addHeaderView(View, Object, boolean)}
*/
public class HeaderGridView extends GridView {
private static final String TAG = "HeaderGridView";
/**
* A class that represents a fixed view in a list, for example a header at the top
* or a footer at the bottom.
*/
private static class FixedViewInfo {
/** The view to add to the grid */
public View view;
public ViewGroup viewContainer;
/** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */
public Object data;
/** <code>true</code> if the fixed view should be selectable in the grid */
public boolean isSelectable;
}
private ArrayList<FixedViewInfo> mHeaderViewInfos = new ArrayList<FixedViewInfo>();
private void initHeaderGridView() {
super.setClipChildren(false);
}
public HeaderGridView(Context context) {
super(context);
initHeaderGridView();
}
public HeaderGridView(Context context, AttributeSet attrs) {
super(context, attrs);
initHeaderGridView();
}
public HeaderGridView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
initHeaderGridView();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
ListAdapter adapter = getAdapter();
if (adapter != null && adapter instanceof HeaderViewGridAdapter) {
((HeaderViewGridAdapter) adapter).setNumColumns(getNumColumns());
}
}
@Override
public void setClipChildren(boolean clipChildren) {
// Ignore, since the header rows depend on not being clipped
}
/**
* Add a fixed view to appear at the top of the grid. If addHeaderView is
* called more than once, the views will appear in the order they were
* added. Views added using this call can take focus if they want.
* <p>
* NOTE: Call this before calling setAdapter. This is so HeaderGridView can wrap
* the supplied cursor with one that will also account for header views.
*
* @param v The view to add.
* @param data Data to associate with this view
* @param isSelectable whether the item is selectable
*/
public void addHeaderView(View v, Object data, boolean isSelectable) {
ListAdapter adapter = getAdapter();
if (adapter != null && ! (adapter instanceof HeaderViewGridAdapter)) {
throw new IllegalStateException(
"Cannot add header view to grid -- setAdapter has already been called.");
}
FixedViewInfo info = new FixedViewInfo();
FrameLayout fl = new FullWidthFixedViewLayout(getContext());
fl.addView(v);
info.view = v;
info.viewContainer = fl;
info.data = data;
info.isSelectable = isSelectable;
mHeaderViewInfos.add(info);
// in the case of re-adding a header view, or adding one later on,
// we need to notify the observer
if (adapter != null) {
((HeaderViewGridAdapter) adapter).notifyDataSetChanged();
}
}
/**
* Add a fixed view to appear at the top of the grid. If addHeaderView is
* called more than once, the views will appear in the order they were
* added. Views added using this call can take focus if they want.
* <p>
* NOTE: Call this before calling setAdapter. This is so HeaderGridView can wrap
* the supplied cursor with one that will also account for header views.
*
* @param v The view to add.
*/
public void addHeaderView(View v) {
addHeaderView(v, null, true);
}
public int getHeaderViewCount() {
return mHeaderViewInfos.size();
}
/**
* Removes a previously-added header view.
*
* @param v The view to remove
* @return true if the view was removed, false if the view was not a header
* view
*/
public boolean removeHeaderView(View v) {
if (mHeaderViewInfos.size() > 0) {
boolean result = false;
ListAdapter adapter = getAdapter();
if (adapter != null && ((HeaderViewGridAdapter) adapter).removeHeader(v)) {
result = true;
}
removeFixedViewInfo(v, mHeaderViewInfos);
return result;
}
return false;
}
private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) {
int len = where.size();
for (int i = 0; i < len; ++i) {
FixedViewInfo info = where.get(i);
if (info.view == v) {
where.remove(i);
break;
}
}
}
@Override
public void setAdapter(ListAdapter adapter) {
if (mHeaderViewInfos.size() > 0) {
HeaderViewGridAdapter hadapter = new HeaderViewGridAdapter(mHeaderViewInfos, adapter);
int numColumns = getNumColumns();
if (numColumns > 1) {
hadapter.setNumColumns(numColumns);
}
super.setAdapter(hadapter);
} else {
super.setAdapter(adapter);
}
}
private class FullWidthFixedViewLayout extends FrameLayout {
public FullWidthFixedViewLayout(Context context) {
super(context);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int targetWidth = HeaderGridView.this.getMeasuredWidth()
- HeaderGridView.this.getPaddingLeft()
- HeaderGridView.this.getPaddingRight();
widthMeasureSpec = MeasureSpec.makeMeasureSpec(targetWidth,
MeasureSpec.getMode(widthMeasureSpec));
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
}
/**
* ListAdapter used when a HeaderGridView has header views. This ListAdapter
* wraps another one and also keeps track of the header views and their
* associated data objects.
*<p>This is intended as a base class; you will probably not need to
* use this class directly in your own code.
*/
private static class HeaderViewGridAdapter implements WrapperListAdapter, Filterable {
// This is used to notify the container of updates relating to number of columns
// or headers changing, which changes the number of placeholders needed
private final DataSetObservable mDataSetObservable = new DataSetObservable();
private final ListAdapter mAdapter;
private int mNumColumns = 1;
// This ArrayList is assumed to NOT be null.
ArrayList<FixedViewInfo> mHeaderViewInfos;
boolean mAreAllFixedViewsSelectable;
private final boolean mIsFilterable;
public HeaderViewGridAdapter(ArrayList<FixedViewInfo> headerViewInfos, ListAdapter adapter) {
mAdapter = adapter;
mIsFilterable = adapter instanceof Filterable;
if (headerViewInfos == null) {
throw new IllegalArgumentException("headerViewInfos cannot be null");
}
mHeaderViewInfos = headerViewInfos;
mAreAllFixedViewsSelectable = areAllListInfosSelectable(mHeaderViewInfos);
}
public int getHeadersCount() {
return mHeaderViewInfos.size();
}
@Override
public boolean isEmpty() {
return (mAdapter == null || mAdapter.isEmpty()) && getHeadersCount() == 0;
}
public void setNumColumns(int numColumns) {
if (numColumns < 1) {
throw new IllegalArgumentException("Number of columns must be 1 or more");
}
if (mNumColumns != numColumns) {
mNumColumns = numColumns;
notifyDataSetChanged();
}
}
private boolean areAllListInfosSelectable(ArrayList<FixedViewInfo> infos) {
if (infos != null) {
for (FixedViewInfo info : infos) {
if (!info.isSelectable) {
return false;
}
}
}
return true;
}
public boolean removeHeader(View v) {
for (int i = 0; i < mHeaderViewInfos.size(); i++) {
FixedViewInfo info = mHeaderViewInfos.get(i);
if (info.view == v) {
mHeaderViewInfos.remove(i);
mAreAllFixedViewsSelectable = areAllListInfosSelectable(mHeaderViewInfos);
mDataSetObservable.notifyChanged();
return true;
}
}
return false;
}
@Override
public int getCount() {
if (mAdapter != null) {
return getHeadersCount() * mNumColumns + mAdapter.getCount();
} else {
return getHeadersCount() * mNumColumns;
}
}
@Override
public boolean areAllItemsEnabled() {
if (mAdapter != null) {
return mAreAllFixedViewsSelectable && mAdapter.areAllItemsEnabled();
} else {
return true;
}
}
@Override
public boolean isEnabled(int position) {
// Header (negative positions will throw an ArrayIndexOutOfBoundsException)
int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
if (position < numHeadersAndPlaceholders) {
return (position % mNumColumns == 0)
&& mHeaderViewInfos.get(position / mNumColumns).isSelectable;
}
// Adapter
final int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = 0;
if (mAdapter != null) {
adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.isEnabled(adjPosition);
}
}
throw new ArrayIndexOutOfBoundsException(position);
}
@Override
public Object getItem(int position) {
// Header (negative positions will throw an ArrayIndexOutOfBoundsException)
int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
if (position < numHeadersAndPlaceholders) {
if (position % mNumColumns == 0) {
return mHeaderViewInfos.get(position / mNumColumns).data;
}
return null;
}
// Adapter
final int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = 0;
if (mAdapter != null) {
adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.getItem(adjPosition);
}
}
throw new ArrayIndexOutOfBoundsException(position);
}
@Override
public long getItemId(int position) {
int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
if (mAdapter != null && position >= numHeadersAndPlaceholders) {
int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.getItemId(adjPosition);
}
}
return -1;
}
@Override
public boolean hasStableIds() {
if (mAdapter != null) {
return mAdapter.hasStableIds();
}
return false;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// Header (negative positions will throw an ArrayIndexOutOfBoundsException)
int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns ;
if (position < numHeadersAndPlaceholders) {
View headerViewContainer = mHeaderViewInfos
.get(position / mNumColumns).viewContainer;
if (position % mNumColumns == 0) {
return headerViewContainer;
} else {
if (convertView == null) {
convertView = new View(parent.getContext());
}
// We need to do this because GridView uses the height of the last item
// in a row to determine the height for the entire row.
convertView.setVisibility(View.INVISIBLE);
convertView.setMinimumHeight(headerViewContainer.getHeight());
return convertView;
}
}
// Adapter
final int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = 0;
if (mAdapter != null) {
adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.getView(adjPosition, convertView, parent);
}
}
throw new ArrayIndexOutOfBoundsException(position);
}
@Override
public int getItemViewType(int position) {
int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
if (position < numHeadersAndPlaceholders && (position % mNumColumns != 0)) {
// Placeholders get the last view type number
return mAdapter != null ? mAdapter.getViewTypeCount() : 1;
}
if (mAdapter != null && position >= numHeadersAndPlaceholders) {
int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.getItemViewType(adjPosition);
}
}
return AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER;
}
@Override
public int getViewTypeCount() {
if (mAdapter != null) {
return mAdapter.getViewTypeCount() + 1;
}
return 2;
}
@Override
public void registerDataSetObserver(DataSetObserver observer) {
mDataSetObservable.registerObserver(observer);
if (mAdapter != null) {
mAdapter.registerDataSetObserver(observer);
}
}
@Override
public void unregisterDataSetObserver(DataSetObserver observer) {
mDataSetObservable.unregisterObserver(observer);
if (mAdapter != null) {
mAdapter.unregisterDataSetObserver(observer);
}
}
@Override
public Filter getFilter() {
if (mIsFilterable) {
return ((Filterable) mAdapter).getFilter();
}
return null;
}
@Override
public ListAdapter getWrappedAdapter() {
return mAdapter;
}
public void notifyDataSetChanged() {
mDataSetObservable.notifyChanged();
}
}
}

代码地址：https://android.googlesource.com/platform/packages/apps/Gallery2/+/idea133/src/com/android/photos/

## GridView 布局：item设置的高度和宽度不起作用、自动适配列数、添加Header和Footer ##

[Android Pro] listView和GridView的item设置的高度和宽度不起作用

GridView的一些特殊属性：