Android实习结束后的阶段性总结

2015年4月14日即将实习结束，在过去的五六个月里，对于Android开发还是学到了很多，临走前将以前做的笔记整理一下，自己也再回顾一次。零散是必然的，也可能只是一小段代码片段，但都是曾经我在学Android是觉得挺有用的知识点。

第一部分：学习SDK下的实例代码时的笔记

1.menu菜单

onCreateOptionMenu(Menu menu){
    .....
//代码生成MenuItem,使用一个自动生成的ID从resources(ids.xml)去避免所有的menu ids冲突
    MenuItem locationItem = menu.add(0,R.id.menu_location,0,"Location");
    locationItem.setIcon(R.drawable.ic_action_location);
    MenuItemCompat.setShowAsAction(locationItem,MenuItem.SHOW_AS_ACTION_IF_ROOM);
........
}
resources/ids.xml:
<resources>
    <!--会自动生成一个id-->
    <item name="menu_location" type="id"/>
</resources>

2.通过strings.xml返回字符串并修改格式

代码中：
    mHeaderTitle.setText(getString(R.string.image_header,mItem.getName(),mItem.getAuthor()));
strings.xml文件配置中：
    <string name="image_header"> %1$s by %2$s </string>

3.通过ActivityOptionsCompat实现Activity过渡是的控件传输
ActivityOptionsCompat activityOptions=ActivityOptionsCompat.makeSceneTransitionAnimation(this,
    new Pair<View,String>(view.findViewById(R.id.imageview_item),DetailActivity.VIEW_NAME_HEADER_IMAGE),
    new Pair<View,String>(view.findViewById(R.id.textview_name),DetailActivity.VIEW_NAME_HEADER_TITLE)
);
ActivityCompat.startActivity(this,intent,activityOptions.toBundle());

获得随Activity启动附加的数据:
ViewCompat.setTransitionName(mHeaderImageView,VIEW_NAME_HEADER_IMAGE);
ViewCompat.setTransitionName(mHeaderTitle,VIEW_NAME_HEADER_TITLE);

//实现添加Transition.TransitionListener监听方法，对转移情况的监听
private boolean addTransitionListener(){
    final Transition transition = getWindow().getSharedElementEnterTransition();
    if(transition != null){
        transition.addListener(new Transition.TransitionListener(){
            public void onTransitionEnd(Transition transition){
                loadFullSizeImage();
                transition.removeListener(this);
            }
        public void onTransitionStart(Transition transition){}
        public void onTransitionCancel(Transition transition){
            transition.removeListener(this);
        }
        public void onTransitionPause(Transition transition){}
        public void onTransitionResume(Transition transition){}
    });
    return true;
    }
    return false;
}

4.加载图片
    Picasso.with( context ).load( url ).into( imageView );

5.使用Android L新特性，解决手机重启是带来的数据灾难
//需要在启动Activity的manifest文件中添加属性:
android:persistableMode="persistAcrossReboots"

//恢复持久化数据
public void onPostCreate(Bundle savedInstanceState,PersistableBundle persistentState){
    super.onPostCreate(savedInstanceState,persistentState);
    if(persistentState != null){
        mDocumentCounter = persistentState.getInt(KEY_EXTRA_NEW_DOCUMENT_COUNTER);
    }
}
//存储持久化数据
public void onSaveInstanceState(Bundle outState,PersistableBundle outPersistentState){
    outPersistentState.putInt(KEY_EXTRA_NEW_DOCUMENT_COUNTER,mDocumentCounter);
    super.onSaveInstanceState(outState,outPersistentState);
}

5.动画视图ViewAnimator
//可以实现ViewAnimator下定义的子视图的动画切换
ViewAnimator output=(ViewAnimator)this.findViewById(R.id.smaple_output);
if(mLogShown){
    output.setDisplayedChild(1);
}else{
    output.setDisplayedChild(0);
}
//重新更新菜单视图
//这个方法会重新执行onCreateOptionsMenu and onPrepareOptionsMenu
    supportInvalidateOptionsMenu();
在xml文件中配置此视图
<ViewAnimator
    android:id="@+id/sample_output"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1">
    <ScrollView
        style="@style/Widget.SampleMessageTile"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <TextView
            style="@style/Widget.SampleMessage"
            ..................../>
    </ScrollView>
    <fragment
        android:name="....."
        ........./>
</ViewAnimator>

6.view.setTag(Object obj)的使用
//对View使用Tag可以缓存对象，从而提高了效率
在Adapter中使用inflate填充布局是可以使用setTag(...)：
public View getView(int position,View convertView,ViewGroup parent){
    final View view;
    final ViewHolder holder;
    if(convertView==null){
         view=mLayoutInflater.inflate(mResourceId,parent,false);
         holder=new ViewHolder();
         assert view != null;
         holder.image=(ImageView)view.findViewById(R.id.meat_image);
         holder.title=(TextView)view.findViewById(R.id.meat_title);
         view.setTag(holder);
    }else{
         view=convertView;
         holder=(ViewHolder)view.getTag();
    }
    Meat meat=getItem(position);
    holder.image.setImageResource(meat.resourceId);
    holder.title.setText(meat.title);
    return view;
}
定义static class ViewHolder:
private static class ViewHolder{
    public ImageView image;
    public TextView title;
}

7.在FramLayout中动画切换布局
private void toggle(){
    mCover.setVisibility(View.VISIBLE);
    FrameLayout before=copyVisibleViews();
    FrameLayout.LayoutParams params=new FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT,FrameLayout.LayoutParams.MATCH_PARENT);
    mCover.addView(befor,params);
    swapAbsListView();
    //在菜单中交换图标
    ActivityCompat.invailidateOptionsMenu(getActivity());
    //开始切换动画
    mAbsListView.post(new Runnable(){
         public void run(){
              Scene scene=new Scene(mCover,copyVisibleViews());
              Transition transition = new AutoTransition();
              transition.addListener(AdapterTransitionFragment.this);
              TransitionManager.go(scene,transition);
          }
    });
}
/**
     * Swap ListView with GridView, or GridView with ListView.
     */
    private void swapAbsListView() {
        // We save the current scrolling position before removing the current list.
        int first = mAbsListView.getFirstVisiblePosition();
        // If the current list is a GridView, we replace it with a ListView. If it is a ListView,
        // a GridView.
        LayoutInflater inflater = LayoutInflater.from(getActivity());
        inflateAbsList(inflater, (ViewGroup) mAbsListView.getParent(),
                mAbsListView instanceof GridView);
        mAbsListView.setAdapter(mAdapter);
        // We restore the scrolling position here.
        mAbsListView.setSelection(first);
        // The new list is ready, and we replace the existing one with it.
        mContent.removeAllViews();
        mContent.addView(mAbsListView);
    }
    /**
     * Copy all the visible views in the mAbsListView into a new FrameLayout and return it.
     *
     * @return a FrameLayout with all the visible views inside.
     */
    private FrameLayout copyVisibleViews() {
        // This is the FrameLayout we return afterwards.
        FrameLayout layout = new FrameLayout(getActivity());
        // The transition framework requires to set ID for all views to be animated.
        layout.setId(ROOT_ID);
        // We only copy visible views.
        int first = mAbsListView.getFirstVisiblePosition();
        int index = 0;
        while (true) {
            // This is one of the views that we copy. Note that the argument for getChildAt is a
            // zero-oriented index, and it doesn‘t usually match with its position in the list.
            View source = mAbsListView.getChildAt(index);
            if (null == source) {
                break;
            }
            // This is the copy of the original view.
            View destination = mAdapter.getView(first + index, null, layout);
            assert destination != null;
            destination.setId(ROOT_ID + first + index);
            FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
                    source.getWidth(), source.getHeight());
            params.leftMargin = (int) source.getX();
            params.topMargin = (int) source.getY();
            layout.addView(destination, params);
            ++index;
        }
        return layout;
    }

8.设置ImmersiveMode(沉浸感模式)
//可以隐藏导航栏、全屏、沉浸感粘连等等特性
public void toggleHideyBar(){
   int uiOptions = getActivity().getWindow().getDecorView().getSystemUiVisibility();
   int newUiOptins = uiOptions;
   boolean isImmersiverModeEnabled =((uiOptions|View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY)==uiOptions);
   if(isImmersiveModeEnabled){
         Log.i(TAG,"immersive mode turn off");
   }else{
         Log.i(TAG,"immersive mode turn on");
   }
   newUiOptions ^= View.SYSTEM_UI_FLAG_HIDE_NAVIGATION;
   newUiOptions ^= View.SYSTEM_UI_FLAG_FULLSCREEN;
   newUiOptions ^= View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;
   getActivity().getWindow().getDecorView().setSystemUiVisibility(newUiOptions);
}

9.BasicTransition动态变换屏幕Scene
//创建一个屏幕的容器根结点
    ViewGroup mSceneRoot =(ViewGroup)view.findViewById(R.id.scene_root);
//创建转换的屏幕
    Scene mScene1 = new Scene(mSceneRoot,(ViewGroup)mSceneRoot.findViewById(R.id.container));
    Scene mScene2 = Scene.getSceneForLayout(mSceneRoot,R.layout.scene2,getActivity());
//为屏幕创建一个转移管理器
    TransitionManager mTransitionManagerForScene3 = TransitionInflater.from(getActivity())
             .inflateTransitionManager(R.transition.scene3_transition_manager,mSceneRoot);
//启动屏幕转换
    TransitionManager.go(mScene1);
//通过转换管理器实现转换
    mTransitionManagerForScene3.transitionTo(mScene3);
//也可以通过转换管理器实现对一个屏幕中的某个控件的属性进行转换
    TransitionManager.beginDelayedTransition(mSceneRoot);
    View square = mSceneRoot.findViewById(R.id.transition_square);
    ViewGroup.LayoutParams params = square.getLayoutParams();
    int newSize = getResources().getDimensionPixelSize(R.dimen.square_size_expanded);
    params.width = newSize;
    params.height = newSize();
    square.setLayoutParams(params);
//每个屏幕的Layout.xml文件的根节点的id需要一样，这样才能实现屏幕的切换
//配置转换器管理的配置文件
<transitionManager xmlns:an.....>
    <transition
         android:toScene="@layout/scene3"
         android:transition="@transition/changebounds_fadein_together"/>
</transitionManager>
在changebounds_fadein_together.xml中：
//对id为transition_title的控件进行淡入动画
<transitionSet xmls:android=....>
    <changeBounds/>
    <fade android:fadingMode="fade_in">
         <targets>
             <target android:targetId="@id/transition_title"/>
         </targets>
    </fade>
</transitionSet>

Android实习结束后的阶段性总结

原文：http://www.cnblogs.com/evilKing/p/4417900.html