ActionMode简介
Android 3.0以前，我们处理列表的长按事件经常使用Context Menu，Android3.0以后，我们有了新的选择：ActionMode。
Android开发者应该都熟悉Context Menu了，Context Menu是悬浮在操作项之上的视图，ActionMode是临时占据了ActionBar的位置。
ActionMode使用步骤
实现ActionMode.Callbak接口，并处理其生命周期方法即可
1.public boolean onCreateActionMode(ActionMode mode, Menu menu)
2.public boolean onPrepareActionMode(ActionMode mode, Menu menu)
3.public boolean onActionItemClicked(ActionMode mode, MenuItem item)
4.public void onDestroyActionMode(ActionMode mode)
重写ActionMode
package com.example.simpleexplore;
import android.app.Activity;
import android.support.v7.view.ActionMode;
import android.view.Menu;
import android.view.MenuItem;
import android.view.Window;
/**
* Created by Administrator on 2017/8/5 0005.
*/
public class ActionModeCallback implements ActionMode.Callback{
private Activity activity;
private Window window;
private ActionListener mActionListener;
private ActionMode actionMode;
private boolean isShowing = true;
public ActionModeCallback(Activity activity,ActionListener listener){
this.activity = activity;
this.window = activity.getWindow();
mActionListener = listener;
}
@Override
public boolean onCreateActionMode(ActionMode mode, Menu menu) {
actionMode = mode;
mode.getMenuInflater().inflate(R.menu.menu_item_top,menu);
return true;
}
@Override
public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
return false;
}
@Override
public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
if(item.getItemId() == R.id.menu_item_done){
if(mActionListener != null){
mActionListener.onFinishAction();
}
}else if(item.getItemId() == R.id.menu_item_delete){
if(mActionListener != null){
mActionListener.onDeleteAction();
}
}
mode.finish();
return false;
}
@Override
public void onDestroyActionMode(ActionMode mode) {
isShowing = false;
if(mActionListener != null){
mActionListener.onDismissAction();
}
}
/**
* 更新title
* @param count
*/
public void updateTitleSelectItemCount(int count){
if(actionMode != null){
actionMode.setTitle(count + (count > 1?"items":"item") + "selected");
}
}
/**
* 退出actionMode
*/
public void dismiss(){
if(actionMode != null){
actionMode.finish();
}
}
/**
* ActionmMode 是否开启
*/
public boolean isShowing(){
return isShowing;
}
/**
* 设置ActionMode的开启
* @param showing
*/
public void setShowing(boolean showing){
isShowing = showing;
}
/**
* actionMode的监听者
*/
public interface ActionListener {
void onFinishAction();
void onDismissAction();
void onDeleteAction();
}
}
```
###定义文件model
```
public class FileWraper {
/**
* 文件
*/
public File file;
/**
* 是否选中
*/
public boolean isSelected = false;
public FileWraper(){
}
public FileWraper(File file){
this.file = file;
}
public FileWraper(File file,boolean isSelected){
this.file = file;
this.isSelected = isSelected;
}
}
```
###定义堆栈
存储每次浏览时访问节点的记录
```
public class FileTreeStack {
//栈顶节点
private Node mTopNode;
//栈内元素个数
private int mSize;
//入栈
public void push(FileShotSnap shotSnap){
Node node = new Node();
node.shotSnap = shotSnap;
node.next = mTopNode;
mTopNode = node;//尾插法
mSize++;
}
//出栈
public FileShotSnap pop(){
if(mTopNode == null) return null;
FileShotSnap shotSnap = mTopNode.shotSnap;
mTopNode = mTopNode.next;
mSize--;
return shotSnap;
}
/**
* 返回堆栈大小
* @return
*/
public int size(){
return mSize;
}
//访问节点
class Node {
FileShotSnap shotSnap;
Node next;//指向下一个节点
}
public static class FileShotSnap {
//母文件夹
public File parent;
//此文件夹下的文件
public List files;
//y上的滑动距离
public int ScrollY;
}
}
```
###MainActvity
```
public class FileExploreActivity extends BaseActivity {
@BindView(R.id.recycler_view)
RecyclerView recyclerView;
private int position;
//根目录
private File rootFile = Environment.getExternalStorage();
//文件访问栈
private FileTreeStack mFileStack;
private ActionModeCallback mCallback;
//当前状态下的母文件夹
File mCurrentFileParent;
//当前所有文件
List mCurrentFiles;
//选中的文件列表
List mSelectedFiles = new ArrayList<>();
private FileAdapter adapter;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_file_explore);
ButterKnife.bind(this);
initView();
}
//回退
@Override
public void onBackPressed() {
if(mFileStack.size() == 0){
super.onBackPressed();
}else {
restoreTreeStack(mFileStack.pop());
}
}
private void initView() {
adapter = new FileAdapter(this,null);
adapter.setOnClickListener(new ListAdapter.OnItemClickListener() {
@Override
public void onClick(View itemView, int position) {
//获取选中文件
FileWraper item = adapter.getItem(position);
if(item.file.isDirectory()){
//如果是在选择状态
if(isInModeAction()){
//选中或取消文件
updateSelectFiles(item,position);
}else {
//进入文件夹 首先堆栈
storeTreeStack();
//加载文件
loadFiles(item.file);
//刷新标题
updateTitle();
}
}
}
});
adapter.setOnItemLongClickListener(new ListAdapter.OnItemLongClickListener() {
@Override
public void onLongClick(View itemView, int position) {
FileWraper item = adapter.getItem(position);
//长按进入选则文件状态
if(item.file.isDirectory()){
if(mCallback == null || !mCallback.isShowing()){
startActionMode();
}
//选中或取消文件
updateSelectFiles(item,position);
}
}
});
recyclerView.setAdapter(adapter);
//加载音乐
loadFiles(rootFile);
}
private void startActionMode() {
if(mCallback == null){
mCallback = new ActionModeCallback(this, new ActionModeCallback.ActionListener() {
@Override
public void onFinishAction() {
//选中
Toast.makeText(FileExploreActivity.this, "选中所有", Toast.LENGTH_SHORT).show();
if(mSelectedFiles.size() > 0){
//操作
} else {
mCallback.dismiss();
}
}
@Override
public void onDismissAction() {
//取消
Toast.makeText(FileExploreActivity.this, "取消续重", Toast.LENGTH_SHORT).show();
clearSelections();
}
@Override
public void onDeleteAction() {
//删除
Toast.makeText(FileExploreActivity.this, "删除选中文件", Toast.LENGTH_SHORT).show();
}
});
}
startSupportActionMode(mCallback);//开启ActionMode ActionBar被替代，进入选择文件状态
mCallback.setShowing(true);
}
//清楚当前所有选中文件
private void clearSelections() {
boolean needClear = mSelectedFiles.size() > 0;
mSelectedFiles.clear();
if(needClear){
adapter.clearSelections();
adapter.notifyDataSetChanged();
}
}
//更新选中或取消
private void updateSelectFiles(FileWraper fileWraper,int position) {
if(fileWraper.file.isFile()) return;
//更新文件选中状态
fileWraper.isSelected = !fileWraper.isSelected;
//添加或取消选中
if(fileWraper.isSelected){
mSelectedFiles.add(fileWraper.file);
}else {
if(mSelectedFiles.indexOf(fileWraper.file) != -1){
mSelectedFiles.remove(fileWraper.file);
}
}
//更新UI
adapter.notifyItemChanged(position);
//更新选中UI
mCallback.updateTitleSelectItemCount(mSelectedFiles.size());
}
/**
* 更新标题
*/
private void updateTitle() {
getSupportActionBar().setTitle(mCurrentFileParent.getName());
}
/**
* 存储节点
*/
private void storeTreeStack() {
//把当前节点加入树栈中
FileTreeStack.FileShotSnap shotSnap = new FileTreeStack.FileShotSnap();
shotSnap.parent = mCurrentFileParent;
shotSnap.files = mCurrentFiles;
mFileStack.push(shotSnap);
}
/**
* 取出节点
* @param top
*/
private void restoreTreeStack(FileTreeStack.FileShotSnap top) {
mCurrentFileParent = top.parent;
mCurrentFiles = top.files;
int scrollOffsetY = top.ScrollY;
adapter.setDate(mCurrentFiles);
adapter.notifyDataSetChanged();
recyclerView.scrollTo(0,scrollOffsetY);
}
/**
* 判断是否在选择模式下
* @return
*/
private boolean isInModeAction() {
//如果第一个条件不符合 就直接返回 不会看第二个
return mCallback != null && mCallback.isShowing();
}
/**
* 加载文件 并更新UI
*/
private void loadFiles(File parent) {
//rxAndroid 加载文件
Subscription subscription = Observable.just(parent)
.flatMap(new Func1>>() {
@Override
public Observable> call(File parent) {
List files = Arrays.asList(parent.listFiles(SystemFileFilter.DEFAULT_INSTANCE));
Collections.sort(files, new Comparator() {
@Override
public int compare(File f1, File f2) {
if (f1.isDirectory() && f2.isFile()) {
return -1;
}
if (f2.isDirectory() && f1.isFile()) {
return 1;
}
return f1.getName().compareToIgnoreCase(f2.getName());
}
});
// 创建文件列表
List fileWrappers = new ArrayList<>(files.size());
for (File file : files) {
fileWrappers.add(new FileWrapper(file));
}
return Observable.just(fileWrappers);
}
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Subscriber>() {
@Override
public void onCompleted() {
}
@Override
public void onError(Throwable throwable) {
Log.e(TAG, "onError: ", throwable);
}
@Override
public void onNext(List files) {
mCurrentFiles = files;
onFileLoaded(parent);
}
});
addSubscription(subscription);
}
private void onFileLoaded(File parent) {
mCurrentFileParent = parent;
//刷新数据
adapter.setDate(mCurrentFiles);
adapter.notifyDataSetChanged();
//进入文件夹的时候滑动到第一个位置就可以
recyclerView.scrollTo(0,0);
}
}
```
适配器及数据的绑定就省略了
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