本文主要是介绍环信UI开源Demo情景分析九、聊天界面（一），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
从会话列表点击一个会话进入聊天界面，现在咱们先来看看聊天界面的清单配置。（在代码中注释比较多，有兴趣的童雪不要只关注文本）
<!-- 聊天页面 --><activityandroid:name=".activity.ChatActivity"android:launchMode="singleTop"android:screenOrientation="portrait"android:theme="@style/horizontal_slide"android:windowSoftInputMode="adjustResize" ></activity>
界面布局相对复杂一点，其中在ListVIew上面还有一个语音提示的布局。
<RelativeLayoutandroid:id="@+id/recording_container"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_centerInParent="true"android:background="@drawable/recording_hint_bg"android:padding="10dp"android:visibility="invisible" ><ImageViewandroid:id="@+id/mic_image"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_centerHorizontal="true"android:src="@drawable/record_animate_01" /><TextViewandroid:id="@+id/recording_hint"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_below="@id/mic_image"android:layout_centerHorizontal="true"android:layout_marginTop="5dp"android:padding="2dp"android:text="@string/move_up_to_cancel"android:textSize="10sp" /></RelativeLayout>
/*** initView*/protected void initView() {//录音布局recordingContainer = findViewById(R.id.recording_container);//录音图标micImage = (ImageView) findViewById(R.id.mic_image);//录音说明recordingHint = (TextView) findViewById(R.id.recording_hint);//聊天列表listView = (ListView) findViewById(R.id.list);//com.easemob.chatuidemo.widget.PasteEditText 输入框mEditTextContent = (PasteEditText) findViewById(R.id.et_sendmessage);//设置输入类型 当前为键盘图标buttonSetModeKeyboard = findViewById(R.id.btn_set_mode_keyboard);//底部布局edittext_layout = (RelativeLayout) findViewById(R.id.edittext_layout);//设置输入类型 当前为声音图标buttonSetModeVoice = findViewById(R.id.btn_set_mode_voice);//发送按钮buttonSend = findViewById(R.id.btn_send);//按下说话按钮buttonPressToSpeak = findViewById(R.id.btn_press_to_speak);//显示表情ViewpagerexpressionViewpager = (ViewPager) findViewById(R.id.vPager);//表情图片emojiIconContainer = (LinearLayout) findViewById(R.id.ll_face_container);//图片，表情，名片等按钮btnContainer = (LinearLayout) findViewById(R.id.ll_btn_container);//位置locationImgview = (ImageView) findViewById(R.id.btn_location);//emoji图标默认iv_emoticons_normal = (ImageView) findViewById(R.id.iv_emoticons_normal);//emoji图标 选择iv_emoticons_checked = (ImageView) findViewById(R.id.iv_emoticons_checked);//加载loadmorePB = (ProgressBar) findViewById(R.id.pb_load_more);//更多 加号图标btnMore = (Button) findViewById(R.id.btn_more);//设置默认图标状态iv_emoticons_normal.setVisibility(View.VISIBLE);iv_emoticons_checked.setVisibility(View.INVISIBLE);//更多 默认视图more = findViewById(R.id.more);//输入框默认背景edittext_layout.setBackgroundResource(R.drawable.input_bar_bg_normal);// 动画资源文件,用于录制语音时micImages = new Drawable[] { //getResources().getDrawable(R.drawable.record_animate_01), //getResources().getDrawable(R.drawable.record_animate_02), //getResources().getDrawable(R.drawable.record_animate_03), //getResources().getDrawable(R.drawable.record_animate_04), //getResources().getDrawable(R.drawable.record_animate_05), //getResources().getDrawable(R.drawable.record_animate_06), //getResources().getDrawable(R.drawable.record_animate_07), //getResources().getDrawable(R.drawable.record_animate_08), //getResources().getDrawable(R.drawable.record_animate_09), //getResources().getDrawable(R.drawable.record_animate_10), //getResources().getDrawable(R.drawable.record_animate_11), //getResources().getDrawable(R.drawable.record_animate_12), //getResources().getDrawable(R.drawable.record_animate_13), //getResources().getDrawable(R.drawable.record_animate_14), };// 表情listreslist = getExpressionRes(35);// 初始化表情viewpagerList<View> views = new ArrayList<View>();View gv1 = getGridChildView(1);View gv2 = getGridChildView(2);views.add(gv1);views.add(gv2);expressionViewpager.setAdapter(new ExpressionPagerAdapter(views));edittext_layout.requestFocus();voiceRecorder = new VoiceRecorder(micImageHandler);buttonPressToSpeak.setOnTouchListener(new PressToSpeakListen());mEditTextContent.setOnFocusChangeListener(new OnFocusChangeListener() {@Overridepublic void onFocusChange(View v, boolean hasFocus) {if (hasFocus) {edittext_layout.setBackgroundResource(R.drawable.input_bar_bg_active);} else {edittext_layout.setBackgroundResource(R.drawable.input_bar_bg_normal);}}});mEditTextContent.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {edittext_layout.setBackgroundResource(R.drawable.input_bar_bg_active);more.setVisibility(View.GONE);iv_emoticons_normal.setVisibility(View.VISIBLE);iv_emoticons_checked.setVisibility(View.INVISIBLE);emojiIconContainer.setVisibility(View.GONE);btnContainer.setVisibility(View.GONE);}});// 监听文字框mEditTextContent.addTextChangedListener(new TextWatcher() {@Overridepublic void onTextChanged(CharSequence s, int start, int before, int count) {if (!TextUtils.isEmpty(s)) {btnMore.setVisibility(View.GONE);buttonSend.setVisibility(View.VISIBLE);} else {btnMore.setVisibility(View.VISIBLE);buttonSend.setVisibility(View.GONE);}}@Overridepublic void beforeTextChanged(CharSequence s, int start, int count, int after) {}@Overridepublic void afterTextChanged(Editable s) {}});}并且动态监听输入框的变换，及时更改表情，发送等控件的状态。
private void setUpView() {//表情点击事件iv_emoticons_normal.setOnClickListener(this);iv_emoticons_checked.setOnClickListener(this);// position = getIntent().getIntExtra("position", -1);//剪切板clipboard = (ClipboardManager) getSystemService(Context.CLIPBOARD_SERVICE);manager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);//隐藏键盘getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);//屏幕睡眠时候关闭软键盘wakeLock = ((PowerManager) getSystemService(Context.POWER_SERVICE)).newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK, "demo");// 判断单聊还是群聊chatType = getIntent().getIntExtra("chatType", CHATTYPE_SINGLE);if (chatType == CHATTYPE_SINGLE) { // 单聊toChatUsername = getIntent().getStringExtra("userId");((TextView) findViewById(R.id.name)).setText(toChatUsername);// conversation =// EMChatManager.getInstance().getConversation(toChatUsername,false);} else {// 群聊findViewById(R.id.container_to_group).setVisibility(View.VISIBLE);//删除聊天记录findViewById(R.id.container_remove).setVisibility(View.GONE);//声音findViewById(R.id.container_voice_call).setVisibility(View.GONE);//视频findViewById(R.id.container_video_call).setVisibility(View.GONE);toChatUsername = getIntent().getStringExtra("groupId");group = EMGroupManager.getInstance().getGroup(toChatUsername);//设置Group nameif (group != null)((TextView) findViewById(R.id.name)).setText(group.getGroupName());else((TextView) findViewById(R.id.name)).setText(toChatUsername);// conversation =// EMChatManager.getInstance().getConversation(toChatUsername,true);}conversation = EMChatManager.getInstance().getConversation(toChatUsername);// 把此会话的未读数置为0conversation.resetUnreadMsgCount();//加载消息// 初始化db时，每个conversation加载数目是getChatOptions().getNumberOfMessagesLoaded// 这个数目如果比用户期望进入会话界面时显示的个数不一样，就多加载一些final List<EMMessage> msgs = conversation.getAllMessages();int msgCount = msgs != null ? msgs.size() : 0;//pagesize = 20if (msgCount < conversation.getAllMsgCount() && msgCount < pagesize) {String msgId = null;if (msgs != null && msgs.size() > 0) {msgId = msgs.get(0).getMsgId();}if (chatType == CHATTYPE_SINGLE) {conversation.loadMoreMsgFromDB(msgId, pagesize);} else {conversation.loadMoreGroupMsgFromDB(msgId, pagesize);}}adapter = new MessageAdapter(this, toChatUsername, chatType);// 显示消息 并设置listview的一些事件listView.setAdapter(adapter);listView.setOnScrollListener(new ListScrollListener());adapter.refreshSelectLast();listView.setOnTouchListener(new OnTouchListener() {@Overridepublic boolean onTouch(View v, MotionEvent event) {//当触摸listview区域时，隐藏键盘、表情hideKeyboard();more.setVisibility(View.GONE);iv_emoticons_normal.setVisibility(View.VISIBLE);iv_emoticons_checked.setVisibility(View.INVISIBLE);emojiIconContainer.setVisibility(View.GONE);btnContainer.setVisibility(View.GONE);return false;}});// 监听当前会话的群聊解散被T事件groupListener = new GroupListener();EMGroupManager.getInstance().addGroupChangeListener(groupListener);// show forward message if the message is not nullString forward_msg_id = getIntent().getStringExtra("forward_msg_id");if (forward_msg_id != null) {// 显示发送要转发的消息forwardMessage(forward_msg_id);}}该方法主要是对聊天内容区的一些设置，通过对聊天类型的判断从而设置Name，在聊天区域被触摸的时候更改输入栏。监听群T事件以及获得转发内容。
接下来看一下点击事件。
/*** 消息图标点击事件* * @param view*/@Overridepublic void onClick(View view) {String st1 = getResources().getString(R.string.not_connect_to_server);int id = view.getId();if (id == R.id.btn_send) {// 点击发送按钮(发文字和表情)String s = mEditTextContent.getText().toString();sendText(s);} else if (id == R.id.btn_take_picture) {selectPicFromCamera();// 点击照相图标} else if (id == R.id.btn_picture) {selectPicFromLocal(); // 点击图片图标} else if (id == R.id.btn_location) { // 位置startActivityForResult(new Intent(this, BaiduMapActivity.class), REQUEST_CODE_MAP);} else if (id == R.id.iv_emoticons_normal) { // 点击显示表情框more.setVisibility(View.VISIBLE);iv_emoticons_normal.setVisibility(View.INVISIBLE);iv_emoticons_checked.setVisibility(View.VISIBLE);btnContainer.setVisibility(View.GONE);emojiIconContainer.setVisibility(View.VISIBLE);hideKeyboard();} else if (id == R.id.iv_emoticons_checked) { // 点击隐藏表情框iv_emoticons_normal.setVisibility(View.VISIBLE);iv_emoticons_checked.setVisibility(View.INVISIBLE);btnContainer.setVisibility(View.VISIBLE);emojiIconContainer.setVisibility(View.GONE);more.setVisibility(View.GONE);} else if (id == R.id.btn_video) {// 点击摄像图标Intent intent = new Intent(ChatActivity.this, ImageGridActivity.class);startActivityForResult(intent, REQUEST_CODE_SELECT_VIDEO);} else if (id == R.id.btn_file) { // 点击文件图标selectFileFromLocal();} else if (id == R.id.btn_voice_call) { // 点击语音电话图标if (!EMChatManager.getInstance().isConnected())Toast.makeText(this, st1, 0).show();elsestartActivity(new Intent(ChatActivity.this, VoiceCallActivity.class).putExtra("username", toChatUsername).putExtra("isComingCall", false));} else if (id == R.id.btn_video_call) { // 视频通话if (!EMChatManager.getInstance().isConnected())Toast.makeText(this, st1, 0).show();elsestartActivity(new Intent(this, VideoCallActivity.class).putExtra("username", toChatUsername).putExtra("isComingCall", false));}}
/*** 发送文本消息* * @param content* message content* @param isResend* boolean resend*/private void sendText(String content) {if (content.length() > 0) {EMMessage message = EMMessage.createSendMessage(EMMessage.Type.TXT);// 如果是群聊，设置chattype,默认是单聊if (chatType == CHATTYPE_GROUP)message.setChatType(ChatType.GroupChat);TextMessageBody txtBody = new TextMessageBody(content);// 设置消息bodymessage.addBody(txtBody);// 设置要发给谁,用户username或者群聊groupidmessage.setReceipt(toChatUsername);// 把messgage加到conversation中conversation.addMessage(message);// 通知adapter有消息变动，adapter会根据加入的这条message显示消息和调用sdk的发送方法adapter.refreshSelectLast();mEditTextContent.setText("");setResult(RESULT_OK);}}照相selectPicFromCamera：
/*** 照相获取图片*/public void selectPicFromCamera() {if (!CommonUtils.isExitsSdcard()) {String st = getResources().getString(R.string.sd_card_does_not_exist);Toast.makeText(getApplicationContext(), st, 0).show();return;}cameraFile = new File(PathUtil.getInstance().getImagePath(), DemoApplication.getInstance().getUserName() + System.currentTimeMillis() + ".jpg");cameraFile.getParentFile().mkdirs();startActivityForResult(new Intent(MediaStore.ACTION_IMAGE_CAPTURE).putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(cameraFile)), REQUEST_CODE_CAMERA);}发送本地图片selectPicFromLocal：
/*** 从图库获取图片*/public void selectPicFromLocal() {Intent intent;if (Build.VERSION.SDK_INT < 19) {intent = new Intent(Intent.ACTION_GET_CONTENT);intent.setType("image/*");} else {intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);}startActivityForResult(intent, REQUEST_CODE_LOCAL);}当点击位置的时候，调用百度地图的SDK（此处不详细说明）。
点击表情按钮的时候，重置more将其更改为表情布局，并且隐藏键盘。
more.setVisibility(View.VISIBLE);iv_emoticons_normal.setVisibility(View.INVISIBLE);iv_emoticons_checked.setVisibility(View.VISIBLE);btnContainer.setVisibility(View.GONE);emojiIconContainer.setVisibility(View.VISIBLE);hideKeyboard();
iv_emoticons_normal.setVisibility(View.VISIBLE);iv_emoticons_checked.setVisibility(View.INVISIBLE);btnContainer.setVisibility(View.VISIBLE);emojiIconContainer.setVisibility(View.GONE);more.setVisibility(View.GONE);
/*** 选择文件*/private void selectFileFromLocal() {Intent intent = null;if (Build.VERSION.SDK_INT < 19) {intent = new Intent(Intent.ACTION_GET_CONTENT);intent.setType("*/*");intent.addCategory(Intent.CATEGORY_OPENABLE);} else {intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);}startActivityForResult(intent, REQUEST_CODE_SELECT_FILE);}当点击摄像图标的时候，启动一个界面ImageGridActivity：
public class ImageGridActivity extends FragmentActivity {private static final String TAG = "ImageGridActivity";@Overrideprotected void onCreate(Bundle savedInstanceState) {
// if (BuildConfig.DEBUG) {
// Utils.enableStrictMode();
// }super.onCreate(savedInstanceState);if (getSupportFragmentManager().findFragmentByTag(TAG) == null) {final FragmentTransaction ft = getSupportFragmentManager().beginTransaction();ft.add(android.R.id.content, new ImageGridFragment(), TAG);ft.commit();}}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {super.onActivityResult(requestCode, resultCode, data);}
} <!-- choose video --><activityandroid:name=".activity.ImageGridActivity"android:screenOrientation="portrait"android:theme="@style/horizontal_slide"android:windowSoftInputMode="stateAlwaysHidden" ></activity>
<GridView xmlns:android="http://schemas.android.com/apk/res/android"android:id="@+id/gridView"android:drawSelectorOnTop="true"android:listSelector="@drawable/photogrid_list_selector"android:layout_width="fill_parent"android:layout_height="fill_parent"android:columnWidth="@dimen/image_thumbnail_size"android:horizontalSpacing="@dimen/image_thumbnail_spacing"android:numColumns="auto_fit"android:stretchMode="columnWidth"android:verticalSpacing="@dimen/image_thumbnail_spacing" >
</GridView>接下来我们来看一下ImageGridFragment里面到底是怎么设置的。
/*** Empty constructor as per the Fragment documentation*/public ImageGridFragment() {}@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);mImageThumbSize = getResources().getDimensionPixelSize(R.dimen.image_thumbnail_size);mImageThumbSpacing = getResources().getDimensionPixelSize(R.dimen.image_thumbnail_spacing);mList = new ArrayList<VideoEntity>();getVideoFile();mAdapter = new ImageAdapter(getActivity());ImageCache.ImageCacheParams cacheParams = new ImageCache.ImageCacheParams();cacheParams.setMemCacheSizePercent(0.25f); // Set memory cache to 25% of// app memory// The ImageFetcher takes care of loading images into our ImageView// children asynchronouslymImageResizer = new ImageResizer(getActivity(), mImageThumbSize);mImageResizer.setLoadingImage(R.drawable.empty_photo);mImageResizer.addImageCache(getActivity().getSupportFragmentManager(), cacheParams);}首先是一个空的构造方法，接下来在onCreate方法中获取设置的布局尺寸，其中有一点需要注意下：
getDimension和getDimensionPixelOffset的功能类似，
都是获取某个dimen的值，但是如果单位是dp或sp，则需要将其乘以density
如果是px，则不乘。并且getDimension返回float，getDimensionPixelOffset返回int.
而getDimensionPixelSize则不管写的是dp还是sp还是px,都会乘以denstiy.
然后定义了一个数组，类型为VideoEntity.
public class VideoEntity {public int ID;public String title;public String filePath;public int size;public int duration;
}
private void getVideoFile() {ContentResolver mContentResolver = getActivity().getContentResolver();Cursor cursor = mContentResolver.query(MediaStore.Video.Media.EXTERNAL_CONTENT_URI, null, null, null, MediaStore.Video.DEFAULT_SORT_ORDER);if (cursor != null && cursor.moveToFirst()) {do {// ID:MediaStore.Audio.Media._IDint id = cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Video.Media._ID));// 名称：MediaStore.Audio.Media.TITLEString title = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.TITLE));// 路径：MediaStore.Audio.Media.DATAString url = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA));// 总播放时长：MediaStore.Audio.Media.DURATIONint duration = cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DURATION));// 大小：MediaStore.Audio.Media.SIZEint size = (int) cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.SIZE));VideoEntity entty = new VideoEntity();entty.ID = id;entty.title = title;entty.filePath = url;entty.duration = duration;entty.size = size;mList.add(entty);} while (cursor.moveToNext());}if (cursor != null) {cursor.close();cursor = null;}}当获取到内容后通过Adapter显示出来：
private class ImageAdapter extends BaseAdapter {private final Context mContext;private int mItemHeight = 0;private RelativeLayout.LayoutParams mImageViewLayoutParams;public ImageAdapter(Context context) {super();mContext = context;mImageViewLayoutParams = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);}@Overridepublic int getCount() {return mList.size() + 1;}@Overridepublic Object getItem(int position) {return (position == 0) ? null : mList.get(position - 1);}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View convertView, ViewGroup container) {ViewHolder holder = null;if (convertView == null) {holder = new ViewHolder();convertView = LayoutInflater.from(mContext).inflate(R.layout.choose_griditem, container, false);holder.imageView = (RecyclingImageView) convertView.findViewById(R.id.imageView);holder.icon = (ImageView) convertView.findViewById(R.id.video_icon);holder.tvDur = (TextView) convertView.findViewById(R.id.chatting_length_iv);holder.tvSize = (TextView) convertView.findViewById(R.id.chatting_size_iv);holder.imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);holder.imageView.setLayoutParams(mImageViewLayoutParams);convertView.setTag(holder);} else {holder = (ViewHolder) convertView.getTag();}// Check the height matches our calculated column widthif (holder.imageView.getLayoutParams().height != mItemHeight) {holder.imageView.setLayoutParams(mImageViewLayoutParams);}// Finally load the image asynchronously into the ImageView, this// also takes care of// setting a placeholder image while the background thread runsString st1 = getResources().getString(R.string.Video_footage);if (position == 0) {holder.icon.setVisibility(View.GONE);holder.tvDur.setVisibility(View.GONE);holder.tvSize.setText(st1);holder.imageView.setImageResource(R.drawable.actionbar_camera_icon);} else {holder.icon.setVisibility(View.VISIBLE);VideoEntity entty = mList.get(position - 1);holder.tvDur.setVisibility(View.VISIBLE);holder.tvDur.setText(DateUtils.toTime(entty.duration));holder.tvSize.setText(TextFormater.getDataSize(entty.size));holder.imageView.setImageResource(R.drawable.empty_photo);mImageResizer.loadImage(entty.filePath, holder.imageView);}return convertView;// END_INCLUDE(load_gridview_item)}/*** Sets the item height. Useful for when we know the column width so the* height can be set to match.* * @param height*/public void setItemHeight(int height) {if (height == mItemHeight) {return;}mItemHeight = height;mImageViewLayoutParams = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, mItemHeight);mImageResizer.setImageSize(height);notifyDataSetChanged();}class ViewHolder {RecyclingImageView imageView;ImageView icon;TextView tvDur;TextView tvSize;}}/*** A holder class that contains cache parameters.*/public static class ImageCacheParams {public int memCacheSize = DEFAULT_MEM_CACHE_SIZE;public int compressQuality = DEFAULT_COMPRESS_QUALITY;public boolean memoryCacheEnabled = DEFAULT_MEM_CACHE_ENABLED;public boolean initDiskCacheOnCreate = DEFAULT_INIT_DISK_CACHE_ON_CREATE;/*** Sets the memory cache size based on a percentage of the max available* VM memory. Eg. setting percent to 0.2 would set the memory cache to* one fifth of the available memory. Throws* {@link IllegalArgumentException} if percent is < 0.01 or > .8.* memCacheSize is stored in kilobytes instead of bytes as this will* eventually be passed to construct a LruCache which takes an int in* its constructor.* * This value should be chosen carefully based on a number of factors* Refer to the corresponding Android Training class for more* discussion: http://developer.android.com/training/displaying-bitmaps/* * @param percent* Percent of available app memory to use to size memory* cache*/public void setMemCacheSizePercent(float percent) {if (percent < 0.01f || percent > 0.8f) {throw new IllegalArgumentException("setMemCacheSizePercent - percent must be "+ "between 0.01 and 0.8 (inclusive)");}memCacheSize = Math.round(percent* Runtime.getRuntime().maxMemory() / 1024);}}在onCreate方法中获取到数据，接下来在onCreateView中设置布局。
@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {final View v = inflater.inflate(R.layout.image_grid_fragment, container, false);final GridView mGridView = (GridView) v.findViewById(R.id.gridView);mGridView.setAdapter(mAdapter);mGridView.setOnItemClickListener(this);mGridView.setOnScrollListener(new AbsListView.OnScrollListener() {@Overridepublic void onScrollStateChanged(AbsListView absListView, int scrollState) {// Pause fetcher to ensure smoother scrolling when flingingif (scrollState == AbsListView.OnScrollListener.SCROLL_STATE_FLING) {// Before Honeycomb pause image loading on scroll to help// with performanceif (!Utils.hasHoneycomb()) {mImageResizer.setPauseWork(true);}} else {mImageResizer.setPauseWork(false);}}@Overridepublic void onScroll(AbsListView absListView, int firstVisibleItem, int visibleItemCount, int totalItemCount) {}});// This listener is used to get the final width of the GridView and then// calculate the// number of columns and the width of each column. The width of each// column is variable// as the GridView has stretchMode=columnWidth. The column width is used// to set the height// of each view so we get nice square thumbnails.mGridView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {@TargetApi(VERSION_CODES.JELLY_BEAN)@Overridepublic void onGlobalLayout() {final int numColumns = (int) Math.floor(mGridView.getWidth() / (mImageThumbSize + mImageThumbSpacing));if (numColumns > 0) {final int columnWidth = (mGridView.getWidth() / numColumns) - mImageThumbSpacing;mAdapter.setItemHeight(columnWidth);if (BuildConfig.DEBUG) {Log.d(TAG, "onCreateView - numColumns set to " + numColumns);}if (Utils.hasJellyBean()) {mGridView.getViewTreeObserver().removeOnGlobalLayoutListener(this);} else {mGridView.getViewTreeObserver().removeGlobalOnLayoutListener(this);}}}});return v;}其中通过暂停显示视频来确保平滑滚动。
有时候需要在onCreate方法中知道某个View组件的宽度和高度等信息，而直接调用View组件的getWidth()、getHeight()、getMeasuredWidth()、getMeasuredHeight()、getTop()、getLeft()等方法是无法获取到真实值的，只会得到0。这是因为View组件布局要在onResume回调后完成。下面提供实现方法，onGlobalLayout回调会在view布局完成时自动调用。
点击事件：
@Overridepublic void onItemClick(AdapterView<?> parent, View v, final int position, long id) {mImageResizer.setPauseWork(true);if (position == 0) {Intent intent = new Intent();intent.setClass(getActivity(), RecorderVideoActivity.class);startActivityForResult(intent, 100);} else {VideoEntity vEntty = mList.get(position - 1);// 限制大小不能超过10Mif (vEntty.size > 1024 * 1024 * 10) {String st = getResources().getString(R.string.temporary_does_not);Toast.makeText(getActivity(), st, Toast.LENGTH_SHORT).show();return;}Intent intent = getActivity().getIntent().putExtra("path", vEntty.filePath).putExtra("dur", vEntty.duration);getActivity().setResult(Activity.RESULT_OK, intent);getActivity().finish();}}其中还有一个RecorderVideoActivity用来录像，此功能在这里不详细分析，有兴趣的同学可以自己去学习以下。
@Overridepublic void onActivityResult(int requestCode, int resultCode, Intent data) {super.onActivityResult(requestCode, resultCode, data);if (resultCode == Activity.RESULT_OK) {if (requestCode == 100) {Uri uri = data.getParcelableExtra("uri");String[] projects = new String[] { MediaStore.Video.Media.DATA, MediaStore.Video.Media.DURATION };Cursor cursor = getActivity().getContentResolver().query(uri, projects, null, null, null);int duration = 0;String filePath = null;if (cursor.moveToFirst()) {// 路径：MediaStore.Audio.Media.DATAfilePath = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA));// 总播放时长：MediaStore.Audio.Media.DURATIONduration = cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DURATION));System.out.println("duration:" + duration);}if (cursor != null) {cursor.close();cursor = null;}getActivity().setResult(Activity.RESULT_OK, getActivity().getIntent().putExtra("path", filePath).putExtra("dur", duration));getActivity().finish();}}}录像之后返回此界面，获取地址和时长后返回聊天界面。
@Overridepublic void onResume() {super.onResume();mImageResizer.setExitTasksEarly(false);mAdapter.notifyDataSetChanged();}@Overridepublic void onDestroy() {super.onDestroy();mImageResizer.closeCache();mImageResizer.clearCache();}还有两个发方法对数据更新及清除缓存。
再次回到聊天界面后调用onActivityResult方法：
/*** onActivityResult*/protected void onActivityResult(int requestCode, int resultCode, Intent data) {super.onActivityResult(requestCode, resultCode, data);if (resultCode == RESULT_CODE_EXIT_GROUP) {setResult(RESULT_OK);finish();return;}if (requestCode == REQUEST_CODE_CONTEXT_MENU) {switch (resultCode) {case RESULT_CODE_COPY: // 复制消息EMMessage copyMsg = ((EMMessage) adapter.getItem(data.getIntExtra("position", -1)));// clipboard.setText(SmileUtils.getSmiledText(ChatActivity.this,// ((TextMessageBody) copyMsg.getBody()).getMessage()));clipboard.setText(((TextMessageBody) copyMsg.getBody()).getMessage());break;case RESULT_CODE_DELETE: // 删除消息EMMessage deleteMsg = (EMMessage) adapter.getItem(data.getIntExtra("position", -1));conversation.removeMessage(deleteMsg.getMsgId());adapter.refreshSeekTo(data.getIntExtra("position", adapter.getCount()) - 1);break;case RESULT_CODE_FORWARD: // 转发消息EMMessage forwardMsg = (EMMessage) adapter.getItem(data.getIntExtra("position", 0));Intent intent = new Intent(this, ForwardMessageActivity.class);intent.putExtra("forward_msg_id", forwardMsg.getMsgId());startActivity(intent);break;default:break;}}if (resultCode == RESULT_OK) { // 清空消息if (requestCode == REQUEST_CODE_EMPTY_HISTORY) {// 清空会话EMChatManager.getInstance().clearConversation(toChatUsername);adapter.refresh();} else if (requestCode == REQUEST_CODE_CAMERA) { // 发送照片if (cameraFile != null && cameraFile.exists())sendPicture(cameraFile.getAbsolutePath());} else if (requestCode == REQUEST_CODE_SELECT_VIDEO) { // 发送本地选择的视频int duration = data.getIntExtra("dur", 0);String videoPath = data.getStringExtra("path");File file = new File(PathUtil.getInstance().getImagePath(), "thvideo" + System.currentTimeMillis());Bitmap bitmap = null;FileOutputStream fos = null;try {if (!file.getParentFile().exists()) {file.getParentFile().mkdirs();}bitmap = ThumbnailUtils.createVideoThumbnail(videoPath, 3);if (bitmap == null) {EMLog.d("chatactivity", "problem load video thumbnail bitmap,use default icon");bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.app_panel_video_icon);}fos = new FileOutputStream(file);bitmap.compress(CompressFormat.JPEG, 100, fos);} catch (Exception e) {e.printStackTrace();} finally {if (fos != null) {try {fos.close();} catch (IOException e) {e.printStackTrace();}fos = null;}if (bitmap != null) {bitmap.recycle();bitmap = null;}}sendVideo(videoPath, file.getAbsolutePath(), duration / 1000);} else if (requestCode == REQUEST_CODE_LOCAL) { // 发送本地图片if (data != null) {Uri selectedImage = data.getData();if (selectedImage != null) {sendPicByUri(selectedImage);}}} else if (requestCode == REQUEST_CODE_SELECT_FILE) { // 发送选择的文件if (data != null) {Uri uri = data.getData();if (uri != null) {sendFile(uri);}}} else if (requestCode == REQUEST_CODE_MAP) { // 地图double latitude = data.getDoubleExtra("latitude", 0);double longitude = data.getDoubleExtra("longitude", 0);String locationAddress = data.getStringExtra("address");if (locationAddress != null && !locationAddress.equals("")) {more(more);sendLocationMsg(latitude, longitude, "", locationAddress);} else {String st = getResources().getString(R.string.unable_to_get_loaction);Toast.makeText(this, st, 0).show();}// 重发消息} else if (requestCode == REQUEST_CODE_TEXT || requestCode == REQUEST_CODE_VOICE || requestCode == REQUEST_CODE_PICTURE || requestCode == REQUEST_CODE_LOCATION || requestCode == REQUEST_CODE_VIDEO || requestCode == REQUEST_CODE_FILE) {resendMessage();} else if (requestCode == REQUEST_CODE_COPY_AND_PASTE) {// 粘贴if (!TextUtils.isEmpty(clipboard.getText())) {String pasteText = clipboard.getText().toString();if (pasteText.startsWith(COPY_IMAGE)) {// 把图片前缀去掉，还原成正常的pathsendPicture(pasteText.replace(COPY_IMAGE, ""));}}} else if (requestCode == REQUEST_CODE_ADD_TO_BLACKLIST) { // 移入黑名单EMMessage deleteMsg = (EMMessage) adapter.getItem(data.getIntExtra("position", -1));addUserToBlacklist(deleteMsg.getFrom());} else if (conversation.getMsgCount() > 0) {adapter.refresh();setResult(RESULT_OK);} else if (requestCode == REQUEST_CODE_GROUP_DETAIL) {adapter.refresh();}}}首先是退出组的消息，收到消息后直接退出该聊天界面。
接下来是上下文菜单的消息，其中转发消息将进入ForwardMessageActivity界面，选择联系人进行转发消息。
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