RecyclerView加载不同item并实现其item点击事件，实现添加常用应用的功能

来源：互联网发布：osx数据恢复编辑：程序博客网时间：2024/06/15 17:20

先上效果图吧

点击加号

勾选需要的应用点击添加

这里出现了三种item的样式，一种是加号，一种是应用图标加文字，最后一种是应用图标加文字还有个checkBox

这里RecyclerView是配合CardView使用的。

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

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：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <TextView        android:id="@+id/tv_sys"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginLeft="@dimen/five"        android:text="@string/systems_apps" />    <android.support.v7.widget.RecyclerView        android:id="@+id/recycleView"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:layout_below="@+id/tv_sys" /></RelativeLayout>

三种item的布局：

card_plus.xml 加号的布局

<?xml version="1.0" encoding="utf-8"?><android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_marginBottom="@dimen/two"    android:layout_marginLeft="@dimen/five"    android:layout_marginRight="@dimen/five"    android:layout_marginTop="@dimen/two">    <RelativeLayout        android:layout_width="match_parent"        android:layout_height="match_parent">        <ImageView            android:id="@+id/img_plus_card"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_centerInParent="true"            android:src="@mipmap/jia_128" />    </RelativeLayout></android.support.v7.widget.CardView>

card_no_check.xml 没有checkBox的item布局

<?xml version="1.0" encoding="utf-8"?><android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="@dimen/hundred_ten"    android:layout_marginBottom="@dimen/two"    android:layout_marginLeft="@dimen/five"    android:layout_marginRight="@dimen/five"    android:layout_marginTop="@dimen/two">    <RelativeLayout        android:layout_width="match_parent"        android:layout_height="match_parent"        android:layout_centerInParent="true">        <ImageView            android:id="@+id/img_card"            android:layout_width="@dimen/fifty"            android:layout_height="@dimen/fifty"            android:layout_centerHorizontal="true"            android:layout_marginTop="@dimen/five"            android:src="@mipmap/ic_launcher" />        <TextView            android:id="@+id/tv_card"            android:layout_width="wrap_content"            android:layout_height="@dimen/sixty"            android:layout_below="@id/img_card"            android:layout_centerHorizontal="true"            android:ellipsize="end"            android:gravity="center"            android:maxLength="25"            android:text="icon1"            android:textColor="@android:color/black"            android:textSize="@dimen/font_s" />    </RelativeLayout></android.support.v7.widget.CardView>

card_check.xml 有checkBox的item布局

<?xml version="1.0" encoding="utf-8"?><android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="@dimen/hundred_ten"    android:layout_marginBottom="@dimen/two"    android:layout_marginLeft="@dimen/five"    android:layout_marginRight="@dimen/five"    android:layout_marginTop="@dimen/two">    <RelativeLayout        android:layout_width="match_parent"        android:layout_height="match_parent"        android:layout_centerInParent="true">        <ImageView            android:id="@+id/img_card2"            android:layout_width="@dimen/fifty"            android:layout_height="@dimen/fifty"            android:layout_centerHorizontal="true"            android:layout_marginTop="@dimen/five"            android:src="@mipmap/ic_launcher" />        <CheckBox            android:id="@+id/checkbox_card2"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_marginLeft="@dimen/ten"            android:layout_marginTop="@dimen/five"            android:background="@drawable/checkbox_style"            android:button="@null" />        <TextView            android:id="@+id/tv_card2"            android:layout_width="wrap_content"            android:layout_height="@dimen/sixty"            android:layout_below="@id/img_card2"            android:layout_centerHorizontal="true"            android:ellipsize="end"            android:gravity="center"            android:maxLength="25"            android:text="icon1"            android:textColor="@android:color/black"            android:textSize="@dimen/font_s" />    </RelativeLayout></android.support.v7.widget.CardView>

重点就在Adapter里面了，RecyclerView继承的是RecyclerView.Adapter<>

因为这里主要是要加载三种不同的item

所以要重写getItemViewType(int position)方法，以决定元素的布局使用哪种类型。由于有三种item，所以也要写三个ViewHolder，继承RecyclerView.ViewHolder.另外还要重写的方法有onCreateViewHolder()用于渲染具体的ViewHolder，onBindViewHolder用于绑定ViewHolder的数据。

RecyclerViewAdapter.java

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> implements View.OnClickListener {    private List<PackageMessage> 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<PackageMessage> list, int flag) {        this.mList = list;        this.mFlag = flag;        mPreference = PackagePreference.getInstance(MyApplication.getContext());    }    /**     * 渲染具体的ViewHolder     *     * @param parent   ViewHolder的容器     * @param viewType 根据该标志实现渲染不同类型的ViewHolder     * @return     */    @Override    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        //加载数据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;        }    }    /**     * 绑定ViewHolder的数据     *     * @param holder     * @param position     */    @Override    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {        PackageMessage message = mList.get(position);        //数据绑定        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();    }    /**     * 决定元素的布局使用哪种类型     *     * @param position     * @return 传递给onCreateViewHolder的第二个参数     */    @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);    }}

由于RecyclerView没有item的点击事件，所以此处在Adapter里面添加item的点击事件，定义一个接口OnRecyclerViewItemClickListener，写一个抽象方法onItemClick(View view,int position)把当前item的position设置进去，在onBindView里面监听item的点击事件。

Activity或Fragment调用处：

我这里是使用的网格布局，所以实例化网格布局管理器GridLayoutManager,如果是线性布局，则实例化LinearLayoutManager

在实例化RecyclerViewAdapter的时候，将item的类型传过去

        //线性布局管理器//        LinearLayoutManager llManager = new LinearLayoutManager(mContext);        GridLayoutManager glManager = new GridLayoutManager(mContext, 4);        //设置布局管理器        mRecyclerView.setLayoutManager(glManager);        mRecyclerView.setHasFixedSize(true);  //每个选项高度固定        mRecyclerView.setItemAnimator(new DefaultItemAnimator());        mAdapter = new RecyclerViewAdapter(mCheckedList, RecyclerViewAdapter.NO_CHECK);        mAdapter.setOnItemClickListener(this);        mRecyclerView.setAdapter(mAdapter);

实现RecyclerViewAdapter.OnRecyclerViewItemClickListener，点击最后一个item(加号)的时候跳转到另一个Activity

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

到这里用RecyclerView显示不同的item还有点击事件也就完成了。

下面说下这个demo的数据存储等

先获取系统安装了的应用信息

在Application里

MyApplication.java

public class MyApplication extends Application {    private static Context mContext;    private PackageManager mPackageManager;    private List<PackageInfo> mPackageInfoList;    private ApplicationInfo mApplicationInfo;    private static List<PackageMessage> mPackList;    @Override    public void onCreate() {        super.onCreate();        mContext = getApplicationContext();        mPackageManager = getPackageManager();        mPackageInfoList = mPackageManager.getInstalledPackages(0);        getPackageMessage();    }    public static Context getContext() {        return mContext;    }    /**     * 得到应用的包名并存储     */    private void getPackageMessage() {        List<PackageInfo> systemApps = new ArrayList<>();        for (PackageInfo apps : mPackageInfoList) {            if ((apps.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) > 0) {                //获取系统应用                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<PackageMessage> getmPackList() {        return mPackList;    }}

PackageMessage是一个存放应用信息的实体类

public class PackageMessage {    private String packageName;  //包名    private Drawable icon;  //图标    private String label;  //名称    private boolean isChecked;  //是否选中    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;    }}

最先出现的RecyclerVIew的Fragment

Fragment2.java

public class Fragment2 extends Fragment implements RecyclerViewAdapter.OnRecyclerViewItemClickListener {    private View mView;    private RecyclerView mRecyclerView;    private List<PackageMessage> mPackList;   //全部的应用的信息列表    private List<PackageMessage> mCheckedList;  //已经被选中的应用列表    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);        //线性布局管理器//        LinearLayoutManager llManager = new LinearLayoutManager(mContext);        GridLayoutManager glManager = new GridLayoutManager(mContext, 4);        //设置布局管理器        mRecyclerView.setLayoutManager(glManager);        mRecyclerView.setHasFixedSize(true);  //每个选项高度固定        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);    }}

这里采用SharedPreference来存储系统中安装的应用包名，key为包名，value为是否选中。另定义了一个字符串来存储已经选中的应用的包名。

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;    }    /**     * 将应用的包名和是否被选中放进去     */    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, "");    }    /**     * 通过包名得知是否被选中     *     * @param packageName     */    public boolean getPackageMessage(String packageName) {        return mSp.getBoolean(packageName, false);    }    /**     * 得到所有选中的应用名数组     *     * @return     */    public String[] getAllCheckedPackageNames() {        String name = getCheckedPackageName();        String[] names = name.split(",");        return names;    }}

至于ListActivity2，就只是将所有应用的图标和名称显示出来。

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