解析Android(安卓)Studio创建的第一个Android(安卓)TV项目

突然想写一篇博客，于是就产生了这篇博客。很多地方都没有理解源码也没有点进去看，所以之后也会继续修改补全。如果对你有一点帮助，或者说你有神马想法或者困惑都可以留言。

一直以来的习惯，拿到一个项目，我就会先去看清单文件，所以先分析一下清单文件吧。

<uses-permission android:name="android.permission.INTERNET" />   //这是申请网络的权限<uses-permission android:name="android.permission.RECORD_AUDIO" />  //这是申请开发音频的权限<uses-feature  android:name="android.hardware.touchscreen"  android:required="false" />           //因为电视一般不支持触屏，所以需要声明一下权限

<uses-feature  android:name="android.software.leanback"  android:required="true" />     //使用一些TV下面的控件时，需要的声明

<activity  android:name=".MainActivity"  android:banner="@drawable/app_icon_your_company"  android:icon="@drawable/app_icon_your_company"  android:label="@string/app_name"  android:logo="@drawable/app_icon_your_company"  android:screenOrientation="landscape">    <intent-filter>        <action android:name="android.intent.action.MAIN" />            <category android:name="android.intent.category.LEANBACK_LAUNCHER" />  //这个地方与手机端开发区别较大，这个主要是声明了这是一个TV项目，如果不加这个，那么运行在TV上时，是找不到这个应用的运行图标的    intent-filter>activity>

然后我就打开了MainActivity，然后我发现里面竟然是空的。随后我就打开了MainActivity的资源文件。

<fragment xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:tools="http://schemas.android.com/tools"  android:id="@+id/main_browse_fragment"  android:name="com.example.administrator.myfirst.MainFragment" //这里是关键点，原来里面是引用了一个碎片。  android:layout_width="match_parent"  android:layout_height="match_parent"  tools:context="com.example.administrator.myfirst.MainActivity"  tools:deviceIds="tv"  tools:ignore="MergeRootFrame" />

然后就可以打开MainFragment。里面有四个方法，我们一一来分析一下。

public void onActivityCreated(Bundle savedInstanceState) {    Log.i(TAG, "onCreate");    super.onActivityCreated(savedInstanceState);    prepareBackgroundManager();    setupUIElements();    loadRows();    setupEventListeners();}

这里大家一看就明白这个方法的作用，初始化。

private void prepareBackgroundManager() {    mBackgroundManager = BackgroundManager.getInstance(getActivity());    mBackgroundManager.attach(getActivity().getWindow());    mDefaultBackground = getResources().getDrawable(R.drawable.default_background);    mMetrics = new DisplayMetrics();    getActivity().getWindowManager().getDefaultDisplay().getMetrics(mMetrics);}

private void setupUIElements() {    // setBadgeDrawable(getActivity().getResources().getDrawable(  // R.drawable.videos_by_google_banner));  setTitle(getString(R.string.browse_title)); // Badge, when set, takes precedent  // over title  setHeadersState(HEADERS_ENABLED);    setHeadersTransitionOnBackEnabled(false); //这里是设置左边引导的显示与否。    // set fastLane (or headers) background color  setBrandColor(getResources().getColor(R.color.background_gradient_start));  //设置左边引导的背景色    // set search icon color  setSearchAffordanceColor(getResources().getColor(R.color.search_opaque));}

这个方法主要作用是产生页面数据

private void loadRows() {    List list = MovieList.setupMovies();  //Movie一个实现了序列化的Bean。setupMovies（）是产生movie数据的方法    mRowsAdapter = new ArrayObjectAdapter(new ListRowPresenter());  //页面数据的适配器    CardPresenter cardPresenter = new CardPresenter();         //这个比较重要下面贴上源码    int i;    for (i = 0; i < NUM_ROWS; i++) {            if (i != 0) {            Collections.shuffle(list);   //打乱list里的数据        }        ArrayObjectAdapter listRowAdapter = new ArrayObjectAdapter(cardPresenter);  //里面要传一个Persenter类型的，Persenter里面有三个抽象方法，复写了Adapter        for (int j = 0; j < NUM_COLS; j++) {            listRowAdapter.add(list.get(j % 5));    //添加Movie，产生页面右边的15个数据        }        HeaderItem header = new HeaderItem(i, MovieList.MOVIE_CATEGORY[i]);  //产生左边的标题数据        mRowsAdapter.add(new ListRow(header, listRowAdapter));   //listRowAdapter是页面右边的数据

 // new ListRow(header, listRowAdapter)这里绑定左边主标题和右边子数据  }

  HeaderItem gridHeader = new HeaderItem(i, "PREFERENCES");

 GridItemPresenter mGridPresenter = new GridItemPresenter();

  ArrayObjectAdapter gridRowAdapter = new ArrayObjectAdapter(mGridPresenter); //里面传了一个Presenter

gridRowAdapter.add(getResources().getString(R.string.grid_view));

 gridRowAdapter.add(getString(R.string.error_fragment));

 gridRowAdapter.add(getResources().getString(R.string.personal_settings));

mRowsAdapter.add(new ListRow(gridHeader, gridRowAdapter));  //看了这个应该很清晰了

 setAdapter(mRowsAdapter); //最后将mRowsAdapter设置}

主要就是实现了每个控件的绑定，设置数据

public class CardPresenter extends Presenter {    private static final String TAG = "CardPresenter";    private static final int CARD_WIDTH = 313;    private static final int CARD_HEIGHT = 176;    private static int sSelectedBackgroundColor;    private static int sDefaultBackgroundColor;    private Drawable mDefaultCardImage;    private static void updateCardBackgroundColor(ImageCardView view, boolean selected) {        int color = selected ? sSelectedBackgroundColor : sDefaultBackgroundColor;        // Both background colors should be set because the view's background is temporarily visible  // during animations.  view.setBackgroundColor(color);        view.findViewById(R.id.info_field).setBackgroundColor(color);    }    @Override    public ViewHolder onCreateViewHolder(ViewGroup parent) {        Log.d(TAG, "onCreateViewHolder");        sDefaultBackgroundColor = parent.getResources().getColor(R.color.default_background);        sSelectedBackgroundColor = parent.getResources().getColor(R.color.selected_background);        /*  * This template uses a default image in res/drawable, but the general case for Android TV  * will require your resources in xhdpi. For more information, see  * https://developer.android.com/training/tv/start/layouts.html#density-resources  */  mDefaultCardImage = parent.getResources().getDrawable(R.drawable.movie);        ImageCardView cardView = new ImageCardView(parent.getContext()) {            @Override            public void setSelected(boolean selected) {                updateCardBackgroundColor(this, selected);  //这句很关键，它实现了当选择改变的时候，选中效果的出现                super.setSelected(selected);            }        };        cardView.setFocusable(true);        cardView.setFocusableInTouchMode(true);        updateCardBackgroundColor(cardView, false);        return new ViewHolder(cardView);    }    @Override    public void onBindViewHolder(Presenter.ViewHolder viewHolder, Object item) {        Movie movie = (Movie) item;        ImageCardView cardView = (ImageCardView) viewHolder.view;        Log.d(TAG, "onBindViewHolder");        if (movie.getCardImageUrl() != null) {            cardView.setTitleText(movie.getTitle());            cardView.setContentText(movie.getStudio());            cardView.setMainImageDimensions(CARD_WIDTH, CARD_HEIGHT);            Glide.with(viewHolder.view.getContext())                    .load(movie.getCardImageUrl())                    .centerCrop()                    .error(mDefaultCardImage)                    .into(cardView.getMainImageView());        }    }    @Override    public void onUnbindViewHolder(Presenter.ViewHolder viewHolder) {        Log.d(TAG, "onUnbindViewHolder");        ImageCardView cardView = (ImageCardView) viewHolder.view;        // Remove references to images so that the garbage collector can free up memory  cardView.setBadgeImage(null);        cardView.setMainImage(null);    }}

这个方法设置了监听

private void setupEventListeners() {    setOnSearchClickedListener(new View.OnClickListener() {        @Override        public void onClick(View view) {            Toast.makeText(getActivity(), "Implement your own in-app search", Toast.LENGTH_LONG)                    .show();        }    });    setOnItemViewClickedListener(new ItemViewClickedListener());    setOnItemViewSelectedListener(new ItemViewSelectedListener());}

这次就先写到这了

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