RecyclerView加載不同item並實現其item點擊事件，實現添加常用應用的功能

先上效果圖吧

點擊加號

勾選需要的應用點擊添加

這裡出現了三種item的樣式，一種是加號，一種是應用圖標加文字，最後一種是應用圖標加文字還有個checkBox

 

這裡RecyclerView是配合CardView使用的。

在AS中使用RecyclerView需要先在build.gradle中添加依賴

 

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.4.0'
    compile 'com.android.support:recyclerview-v7:23.4.0'
    compile 'com.android.support:cardview-v7:23.4.0'
}

 

布局文件：

 

 

三種item的布局：

card_plus.xml 加號的布局

 

 

 

card_no_check.xml 沒有checkBox的item布局

 

 

 

card_check.xml 有checkBox的item布局

 

 

重點就在Adapter裡面了，RecyclerView繼承的是RecyclerView.Adapter<>

因為這裡主要是要加載三種不同的item

所以要重寫getItemViewType(int position)方法，以決定元素的布局使用哪種類型。由於有三種item，所以也要寫三個ViewHolder，繼承RecyclerView.ViewHolder.另外還要重寫的方法有onCreateViewHolder()用於渲染具體的ViewHolder，onBindViewHolder用於綁定ViewHolder的數據。

RecyclerViewAdapter.java

 

public class RecyclerViewAdapter extends RecyclerView.Adapter implements View.OnClickListener {

    private List mList;
    private PackagePreference mPreference;
    private OnRecyclerViewItemClickListener mListener;
    private static int mFlag;
    public final static int NO_CHECK = 0;
    public final static int CHECK = 1;
    public final static int PLUS = 2;

    public RecyclerViewAdapter(List list, int flag) {
        this.mList = list;
        this.mFlag = flag;
        mPreference = PackagePreference.getInstance(MyApplication.getContext());
    }
    /**
     * 渲染具體的ViewHolder
     *
     * @param parent   ViewHolder的容器
     * @param viewType 根據該標志實現渲染不同類型的ViewHolder
     * @return
     */
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        //加載數據item的布局，生成VH返回
        if (viewType == NO_CHECK) {
            return new NoCheckViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.card_no_check, parent, false));
        } else if (viewType == CHECK) {
            return new CheckViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.card_check, parent, false));
        } else if (viewType == PLUS) {
            return new PlusViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.card_plus, parent, false));
        } else {
            return null;
        }
    }

    /**
     * 綁定ViewHolder的數據
     *
     * @param holder
     * @param position
     */
    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        PackageMessage message = mList.get(position);
        //數據綁定
        if (holder instanceof NoCheckViewHolder) {
            bindNoCheckViewHolder(message, (NoCheckViewHolder) holder);
        } else if (holder instanceof CheckViewHolder) {
            bindCheckViewHolder(message, (CheckViewHolder) holder);
        }
        holder.itemView.setTag(position);
        holder.itemView.setOnClickListener(this);
    }

    @Override
    public int getItemCount() {
        if (null == mList) {
            return 0;
        }
        return mList.size();
    }

    /**
     * 決定元素的布局使用哪種類型
     *
     * @param position
     * @return 傳遞給onCreateViewHolder的第二個參數
     */
    @Override
    public int getItemViewType(int position) {
        if (mFlag == NO_CHECK) {
            if (position == mList.size() - 1) {
                return PLUS;
            }
            return NO_CHECK;
        } else if (mFlag == CHECK) {
            return CHECK;
        } else {
            return 100;
        }
    }

    private void bindNoCheckViewHolder(PackageMessage message, NoCheckViewHolder holder) {
        holder.tv.setText(message.getLabel());
        holder.img.setImageDrawable(message.getIcon());
    }

    private void bindCheckViewHolder(PackageMessage message, final CheckViewHolder holder) {
        holder.tv2.setText(message.getLabel());
        holder.img2.setImageDrawable(message.getIcon());
        final String packageName = message.getPackageName();
        holder.checkBox2.setChecked(mPreference.getPackageMessage(packageName));
        holder.checkBox2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (holder.checkBox2.isChecked()) {
                    mPreference.putPackageMessage(packageName, true);
                } else {
                    mPreference.putPackageMessage(packageName, false);
                }
            }
        });
    }

    public static class NoCheckViewHolder extends RecyclerView.ViewHolder {
        public ImageView img;
        public TextView tv;

        public NoCheckViewHolder(View itemView) {
            super(itemView);
            img = (ImageView) itemView.findViewById(R.id.img_card);
            tv = (TextView) itemView.findViewById(R.id.tv_card);
        }
    }

    public static class CheckViewHolder extends RecyclerView.ViewHolder {
        public CheckBox checkBox2;
        public ImageView img2;
        public TextView tv2;

        public CheckViewHolder(View itemView) {
            super(itemView);
            checkBox2 = (CheckBox) itemView.findViewById(R.id.checkbox_card2);
            img2 = (ImageView) itemView.findViewById(R.id.img_card2);
            tv2 = (TextView) itemView.findViewById(R.id.tv_card2);
        }
    }

    public static class PlusViewHolder extends RecyclerView.ViewHolder {
        public ImageView img_plus_card;

        public PlusViewHolder(View itemView) {
            super(itemView);
            img_plus_card = (ImageView) itemView.findViewById(R.id.img_plus_card);
        }
    }

    @Override
    public void onClick(View v) {
        if (null != mListener) {
            mListener.onItemClick(v, (Integer) v.getTag());
        }
    }

    public void setOnItemClickListener(OnRecyclerViewItemClickListener listener) {
        this.mListener = listener;
    }

    public interface OnRecyclerViewItemClickListener {
        void onItemClick(View view, int position);
    }
}

由於RecyclerView沒有item的點擊事件，所以此處在Adapter裡面添加item的點擊事件，定義一個接口OnRecyclerViewItemClickListener，寫一個抽象方法onItemClick(View view,int position)把當前item的position設置進去，在onBindView裡面監聽item的點擊事件。

 

 

Activity或Fragment調用處：

我這裡是使用的網格布局，所以實例化網格布局管理器GridLayoutManager,如果是線性布局，則實例化LinearLayoutManager

在實例化RecyclerViewAdapter的時候，將item的類型傳過去

 

        //線性布局管理器
//        LinearLayoutManager llManager = new LinearLayoutManager(mContext);
        GridLayoutManager glManager = new GridLayoutManager(mContext, 4);
        //設置布局管理器
        mRecyclerView.setLayoutManager(glManager);
        mRecyclerView.setHasFixedSize(true);  //每個選項高度固定
        mRecyclerView.setItemAnimator(new DefaultItemAnimator());
        mAdapter = new RecyclerViewAdapter(mCheckedList, RecyclerViewAdapter.NO_CHECK);
        mAdapter.setOnItemClickListener(this);
        mRecyclerView.setAdapter(mAdapter);

實現RecyclerViewAdapter.OnRecyclerViewItemClickListener，點擊最後一個item(加號)的時候跳轉到另一個Activity

 

 

    @Override
    public void onItemClick(View view, int position) {
        if (position == (mCheckedList.size() - 1)) {
            startActivityForResult(new Intent(getActivity(), ListActivity2.class), 1);
        }
    }

到這裡用RecyclerView顯示不同的item還有點擊事件也就完成了。

 

 

 

下面說下這個demo的數據存儲等

先獲取系統安裝了的應用信息

在Application裡

MyApplication.java

 

public class MyApplication extends Application {

    private static Context mContext;
    private PackageManager mPackageManager;
    private List mPackageInfoList;
    private ApplicationInfo mApplicationInfo;
    private static List mPackList;

    @Override
    public void onCreate() {
        super.onCreate();
        mContext = getApplicationContext();
        mPackageManager = getPackageManager();
        mPackageInfoList = mPackageManager.getInstalledPackages(0);
        getPackageMessage();
    }

    public static Context getContext() {
        return mContext;
    }
    /**
     * 得到應用的包名並存儲
     */
    private void getPackageMessage() {
        List systemApps = new ArrayList<>();
        for (PackageInfo apps : mPackageInfoList) {
            if ((apps.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) > 0) {
                //獲取系統應用
                systemApps.add(apps);
            }
        }
        int size = systemApps.size();
        mPackList = new ArrayList<>();
        PackageMessage message;
        for (int i = 0; i < size; i++) {
            message = new PackageMessage();
            PackageInfo packageInfo = systemApps.get(i);
            mApplicationInfo = packageInfo.applicationInfo;
            String packageName = mApplicationInfo.packageName;
            Drawable drawable = mPackageManager.getApplicationIcon(mApplicationInfo);
            String label = (String) mPackageManager.getApplicationLabel(mApplicationInfo);
            message.setIcon(drawable);
            message.setLabel(label);
            message.setPackageName(packageName);
            mPackList.add(message);
        }
    }
    public static List getmPackList() {
        return mPackList;
    }
}

PackageMessage是一個存放應用信息的實體類

public class PackageMessage {
    private String packageName;  //包名
    private Drawable icon;  //圖標
    private String label;  //名稱
    private boolean isChecked;  //是否選中

    public String getPackageName() {
        return packageName;
    }

    public void setPackageName(String packageName) {
        this.packageName = packageName;
    }

    public Drawable getIcon() {
        return icon;
    }

    public void setIcon(Drawable icon) {
        this.icon = icon;
    }

    public String getLabel() {
        return label;
    }

    public void setLabel(String label) {
        this.label = label;
    }

    public boolean isChecked() {
        return isChecked;
    }

    public void setIsChecked(boolean isChecked) {
        this.isChecked = isChecked;
    }
}

最先出現的RecyclerVIew的Fragment

 

Fragment2.java

 

public class Fragment2 extends Fragment implements RecyclerViewAdapter.OnRecyclerViewItemClickListener {
    private View mView;
    private RecyclerView mRecyclerView;
    private List mPackList;   //全部的應用的信息列表
    private List mCheckedList;  //已經被選中的應用列表
    private RecyclerViewAdapter mAdapter;
    private Context mContext;
    private PackagePreference mPreference;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        mView = inflater.inflate(R.layout.fragment2, container, false);
        mRecyclerView = (RecyclerView) mView.findViewById(R.id.recycleView);
        return mView;
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        //線性布局管理器
//        LinearLayoutManager llManager = new LinearLayoutManager(mContext);
        GridLayoutManager glManager = new GridLayoutManager(mContext, 4);
        //設置布局管理器
        mRecyclerView.setLayoutManager(glManager);
        mRecyclerView.setHasFixedSize(true);  //每個選項高度固定
        mRecyclerView.setItemAnimator(new DefaultItemAnimator());
        mContext = MyApplication.getContext();
        mPreference = PackagePreference.getInstance(mContext);
        mPackList = MyApplication.getmPackList();
        showCheckedList();
    }

    @Override
    public void onItemClick(View view, int position) {
        if (position == (mCheckedList.size() - 1)) {
            startActivityForResult(new Intent(getActivity(), ListActivity2.class), 1);
        }
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == 1 && resultCode == 2) {
            showCheckedList();
        }
    }

    private void showCheckedList() {
        mCheckedList = new ArrayList<>();
        String[] names = mPreference.getAllCheckedPackageNames();
        for (int i = 0; i < names.length; i++) {
            for (int j = 0; j < mPackList.size(); j++) {
                if (names[i].equals(mPackList.get(j).getPackageName())) {
                    mCheckedList.add(mPackList.get(j));
                    break;
                }
            }
        }
        PackageMessage m = new PackageMessage();
        mCheckedList.add(m);
        mAdapter = new RecyclerViewAdapter(mCheckedList, RecyclerViewAdapter.NO_CHECK);
        mAdapter.setOnItemClickListener(this);
        mRecyclerView.setAdapter(mAdapter);
    }
}

這裡采用SharedPreference來存儲系統中安裝的應用包名，key為包名，value為是否選中。另定義了一個字符串來存儲已經選中的應用的包名。

 

PackagePreference.java

 

public class PackagePreference {

    private String PREFS_CHECKED_NAME = "CheckedPackageName";

    private Context mContext;
    private static PackagePreference mPackagePreference;
    private SharedPreferences mSp;
    private SharedPreferences.Editor mEditor;
    private String TAG = "PackagePreference";
    private StringBuilder mCheckedPackageName;

    private PackagePreference(Context context) {
        this.mContext = context;
        mSp = context.getSharedPreferences("checkedPackage", Context.MODE_PRIVATE);
        mEditor = mSp.edit();
    }

    public static PackagePreference getInstance(Context context) {
        if (mPackagePreference == null) {
            mPackagePreference = new PackagePreference(context);
        }
        return mPackagePreference;
    }

    /**
     * 將應用的包名和是否被選中放進去
     */
    public void putPackageMessage(String packageName, boolean isChecked) {
        mEditor.putBoolean(packageName, isChecked).commit();
        String name = getCheckedPackageName();
        mCheckedPackageName = new StringBuilder(name);
        if (isChecked) {
            mCheckedPackageName.append(packageName).append(",");
        } else {
            int index = mCheckedPackageName.indexOf(packageName);
            mCheckedPackageName.delete(index, index + packageName.length() + 1);
        }
        putCheckedPackageName();
    }

    public void putCheckedPackageName() {
        mEditor.putString(PREFS_CHECKED_NAME, mCheckedPackageName.toString()).commit();
    }

    public String getCheckedPackageName() {
        return mSp.getString(PREFS_CHECKED_NAME, "");
    }

    /**
     * 通過包名得知是否被選中
     *
     * @param packageName
     */
    public boolean getPackageMessage(String packageName) {
        return mSp.getBoolean(packageName, false);
    }

    /**
     * 得到所有選中的應用名數組
     *
     * @return
     */
    public String[] getAllCheckedPackageNames() {
        String name = getCheckedPackageName();
        String[] names = name.split(",");
        return names;
    }
}

至於ListActivity2，就只是將所有應用的圖標和名稱顯示出來。