我试图从此处找到的示例对gridview进行反向工程： https://github.com/liaohuqiu/android-GridViewWithHeaderAndFooter
使用他的源代码在这里：
，但是当我尝试在其中显示图像时，仍然会出现转换错误。 我想自己学习如何做，因为当我尝试使用glide加载图像时，他的代码崩溃了。
这是我拥有的gridview代码：
package customgridapp.customgridview;
import android.annotation.SuppressLint;
import android.content.Context;
import android.database.DataSetObservable;
import android.database.DataSetObserver;
import android.os.Build;
import android.util.AttributeSet;
import android.util.Log;
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;
public class TestFooterGridView extends GridView{
private static final String TAG = "TestFooterGridView";
/**
* 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 ArrayList<FixedViewInfo> mFooterViewInfos = new ArrayList<FixedViewInfo>();
private int mRequestedNumColumns;
private int mNumColmuns = 1;
private void initHeaderGridView() {
super.setClipChildren(false);
}
public TestFooterGridView(Context context) {
super(context);
initHeaderGridView();
}
public TestFooterGridView(Context context, AttributeSet attrs) {
super(context, attrs);
initHeaderGridView();
}
public TestFooterGridView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
initHeaderGridView();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (mRequestedNumColumns != AUTO_FIT) {
mNumColmuns = mRequestedNumColumns;
}
if (mNumColmuns <= 0) {
mNumColmuns = 1;
}
ListAdapter adapter = getAdapter();
if (adapter != null && adapter instanceof FooterViewGridAdapter) {
((FooterViewGridAdapter) 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 HeaderFooterGridView 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 FooterViewGridAdapter)) {
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) {
((FooterViewGridAdapter) adapter).notifyDataSetChanged();
}
}
/**
* Add a fixed view to appear at the bottom of the grid. If addFooterView 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 HeaderFooterGridView 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 addFooterView(View v, Object data, boolean isSelectable) {
ListAdapter adapter = getAdapter();
if (adapter != null && !(adapter instanceof FooterViewGridAdapter)) {
throw new IllegalStateException(
"Cannot add footer 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;
mFooterViewInfos.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) {
((FooterViewGridAdapter) adapter).notifyDataSetChanged();
}
}
/**
* Add a fixed view to appear at the bottom of the grid. If addFooterView 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 HeaderFooterGridView can wrap
* the supplied cursor with one that will also account for header views.
*
* @param v The view to add.
*/
public void addFooterView(View v) {
addFooterView(v, null, 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 || mFooterViewInfos.size() > 0) {
FooterViewGridAdapter hadapter = new FooterViewGridAdapter(mFooterViewInfos, 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 = TestFooterGridView.this.getMeasuredWidth()
- TestFooterGridView.this.getPaddingLeft()
- TestFooterGridView.this.getPaddingRight();
widthMeasureSpec = MeasureSpec.makeMeasureSpec(targetWidth,
MeasureSpec.getMode(widthMeasureSpec));
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
}
@Override
public void setNumColumns(int numColumns) {
super.setNumColumns(numColumns);
// Store specified value for less than Honeycomb.
mRequestedNumColumns = numColumns;
}
@Override
@SuppressLint("NewApi")
public int getNumColumns() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
return super.getNumColumns();
}
// Return value for less than Honeycomb.
return mNumColmuns;
}
/**
* ListAdapter used when a HeaderFooterGridView 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 FooterViewGridAdapter 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> mFooterViewInfos;
boolean mAreAllFixedViewsSelectable;
private final boolean mIsFilterable;
public FooterViewGridAdapter(ArrayList<FixedViewInfo> footerViewInfos, ListAdapter adapter) {
mAdapter = adapter;
mIsFilterable = adapter instanceof Filterable;
if (footerViewInfos == null) {
throw new IllegalArgumentException("footerViewInfos cannot be null");
}
mFooterViewInfos = footerViewInfos;
mAreAllFixedViewsSelectable = areAllListInfosSelectable(mFooterViewInfos);
}
public int getHeadersCount() {
return 0;
}
public int getFootersCount() {
return mFooterViewInfos.size();
}
@Override
public boolean isEmpty() {
return (mAdapter == null || mAdapter.isEmpty()) && getHeadersCount() == 0 && getFootersCount() == 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 removeFooter(View v) {
for (int i = 0; i < mFooterViewInfos.size(); i++) {
FixedViewInfo info = mFooterViewInfos.get(i);
if (info.view == v) {
mFooterViewInfos.remove(i);
mAreAllFixedViewsSelectable = areAllListInfosSelectable(mFooterViewInfos);
mDataSetObservable.notifyChanged();
return true;
}
}
return false;
}
@Override
public int getCount() {
if (mAdapter != null) {
final int lastRowItemCount = (mAdapter.getCount() % mNumColumns);
final int emptyItemCount = ((lastRowItemCount == 0) ? 0 : mNumColumns - lastRowItemCount);
return (getHeadersCount() * mNumColumns) + mAdapter.getCount() + emptyItemCount + (getFootersCount() * mNumColumns);
} else {
return (getHeadersCount() * mNumColumns) + (getFootersCount() * 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
if (position < numHeadersAndPlaceholders + mAdapter.getCount()) {
final int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = 0;
if (mAdapter != null) {
adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.isEnabled(adjPosition);
}
}
}
// Empty item
final int lastRowItemCount = (mAdapter.getCount() % mNumColumns);
final int emptyItemCount = ((lastRowItemCount == 0) ? 0 : mNumColumns - lastRowItemCount);
if (position < numHeadersAndPlaceholders + mAdapter.getCount() + emptyItemCount) {
// return false;
return (position % mNumColumns == 0)
&& mFooterViewInfos.get((position - numHeadersAndPlaceholders - mAdapter.getCount() - emptyItemCount) / mNumColumns).isSelectable;
}
// Footer
int numFootersAndPlaceholders = getFootersCount() * mNumColumns;
if (position < numHeadersAndPlaceholders + mAdapter.getCount() + emptyItemCount + numFootersAndPlaceholders) {
return (position % mNumColumns == 0)
&& mFooterViewInfos.get((position - numHeadersAndPlaceholders - mAdapter.getCount() - emptyItemCount) / mNumColumns).isSelectable;
}
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 0; //mHeaderViewInfos.get(position / mNumColumns).data;
}
return null;
}
// Adapter
if (position < numHeadersAndPlaceholders + mAdapter.getCount()) {
final int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = 0;
if (mAdapter != null) {
adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.getItem(adjPosition);
}
}
}
// Empty item
final int lastRowItemCount = (mAdapter.getCount() % mNumColumns);
Log.e(TAG, "Lastrowitemcount:" + lastRowItemCount);
final int emptyItemCount = ((lastRowItemCount == 0) ? 0 : mNumColumns - lastRowItemCount);
Log.e(TAG, "emptyitemcount:" + emptyItemCount);
if (position < numHeadersAndPlaceholders + mAdapter.getCount() + emptyItemCount) {
/*return null;*/
return mFooterViewInfos.get((position - numHeadersAndPlaceholders - mAdapter.getCount() - emptyItemCount) / mNumColumns).data;
}
// Footer
int numFootersAndPlaceholders = getFootersCount() * mNumColumns;
if (position < numHeadersAndPlaceholders + mAdapter.getCount() + emptyItemCount + numFootersAndPlaceholders) {
if (position % mNumColumns == 0) {
return mFooterViewInfos.get((position - numHeadersAndPlaceholders - mAdapter.getCount() - emptyItemCount) / mNumColumns).data;
}
}
throw new ArrayIndexOutOfBoundsException(position);
}
@Override
public long getItemId(int position) {
int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
if (mAdapter != null) {
if (position >= numHeadersAndPlaceholders && position < numHeadersAndPlaceholders + mAdapter.getCount()) {
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 null; //headerViewContainer;
} else {
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
// TODO Current implementation may not be enough in the case of 3 or more column. May need to be careful on the INVISIBLE View height.
if (position < numHeadersAndPlaceholders + mAdapter.getCount()) {
final int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = 0;
if (mAdapter != null) {
adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
convertView = mAdapter.getView(adjPosition, convertView, parent);
convertView.setVisibility(View.VISIBLE);
return convertView;
}
}
}
// Empty item
final int lastRowItemCount = (mAdapter.getCount() % mNumColumns);
Log.e(TAG, "Lastrowitemcount:" + lastRowItemCount);
final int emptyItemCount = ((lastRowItemCount == 0) ? 0 : mNumColumns - lastRowItemCount);
Log.e(TAG, "Emptyitemcount:" + emptyItemCount);
if (position < numHeadersAndPlaceholders + mAdapter.getCount() + emptyItemCount) {
// 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.
// TODO Current implementation may not be enough in the case of 3 or more column. May need to be careful on the INVISIBLE View height.
convertView = mAdapter.getView(mAdapter.getCount() - 1, convertView, parent);
convertView.setVisibility(View.INVISIBLE);
return convertView;
}
// Footer
int numFootersAndPlaceholders = getFootersCount() * mNumColumns;
if (position < numHeadersAndPlaceholders + mAdapter.getCount() + emptyItemCount + numFootersAndPlaceholders) {
View footerViewContainer = mFooterViewInfos
.get((position - numHeadersAndPlaceholders - mAdapter.getCount() - emptyItemCount) / mNumColumns).viewContainer;
if (position % mNumColumns == 0) {
return footerViewContainer;
} else {
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(footerViewContainer.getHeight());
return convertView;
}
}
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 && position < numHeadersAndPlaceholders + mAdapter.getCount() + (mNumColumns - (mAdapter.getCount() % mNumColumns))) {
int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.getItemViewType(adjPosition);
} else if (adapterCount != 0 && mNumColumns != 1) {
return mAdapter.getItemViewType(adapterCount - 1);
}
}
int numFootersAndPlaceholders = getFootersCount() * mNumColumns;
if (mAdapter != null && position < numHeadersAndPlaceholders + mAdapter.getCount() + numFootersAndPlaceholders) {
return mAdapter != null ? mAdapter.getViewTypeCount() : 1;
}
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();
}
}
}
我试图通过删除与页眉有关的所有代码并仅查看他对页脚的操作来理解他的代码。
简而言之：如何在三列gridview中添加页脚？ 我需要什么？
答案 0 :(得分：0)
您不需要任何库。只是尝试这个...。
像这样创建Layout .....
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v4.widget.NestedScrollView
android:id="@+id/nestedScrollView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:overScrollMode="never">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="@+id/header"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="20dp"
android:text="Header"
android:textColor="@color/white"
android:textSize="16sp" />
<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/footer"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="20dp"
android:text="Footer"
android:textColor="@color/white"
android:textSize="16sp" />
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
</LinearLayout>
然后在您的Activity或Fragment中使用此代码...
RecyclerView recyclerView = findViewById(R.id.recyclerView);
ViewCompat.setNestedScrollingEnabled(recyclerView, false);
GridLayoutManager mLayoutManager = new GridLayoutManager(activity, 3);
recyclerView.setLayoutManager(mLayoutManager);
adapter = new YourCustomAdapter(this);
recyclerView.setAdapter(adapter);
注意：-在我看来，不依赖于库。如果他们将来会删除它，那么您必须再次更改您的工作。如果要使用库，请尝试在项目中导入其GitHub整个模块。因此，您不必依赖于它们的更改。我发生了一件事情，我在应用中使用了图像压缩库。一年后，他们删除了他们的图书馆，我不得不在那个模块上再次工作。而且，如果您使用的是一些著名的公司图书馆，则可以使用 Facebook ， Google ， Square 或更多。许多大公司也依赖他们的图书馆。