Android 图片选择器

图片选择器，遍历系统所有图片并显示，点击查看大图，长按选中，并将结果返回

字体颜色res/color建立text_selecor.xml

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:color="@android:color/white" android:state_enabled="true"/>
    <item android:color="@android:color/darker_gray" android:state_enabled="false"/>
</selector>

图片选择按钮

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_checked="true" android:drawable="@mipmap/sel_check"/>
    <item android:state_checked="false" android:drawable="@mipmap/sel_nor"/>
</selector>

遍历之后将所有图片显示

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:background="@android:color/background_dark"
    android:layout_height="match_parent">
    <ImageView
        android:id="@+id/iv_img"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scaleType="centerCrop"
        android:layout_margin="10dp"
        android:src="@mipmap/camera"/>
    <CheckBox
        android:id="@+id/cb_btn"
        android:layout_margin="15dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:button="@drawable/item_selector"/>

</RelativeLayout>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.lesson10_picselectordemo.MainActivity">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@android:color/holo_blue_dark"
        android:padding="10dp">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:text="图片选择"
            android:textColor="@android:color/white"
            android:textSize="18sp" />

        <TextView
            android:id="@+id/tv_finish"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:enabled="false"
            android:text="完成"
            android:textColor="@color/text_selector" />

    </RelativeLayout>

    <GridView
        android:id="@+id/gv_image"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:numColumns="4"/>
</LinearLayout>

适配器，当适配数据类型不确定时，可以使用泛型.继承BaseAdapter都要重写那几个方法，这里将他们抽出来

/**
 * 适配数据类型不确定，可以使用泛型
 * 也可以是使用extends限定泛型，比如接口IGetName有个getName()方法，只要T继承IGetName实现方法，就可以使用该方法
 * Created by Administrator on 2016/10/24 0024.
 */

public abstract class ListItemAdapter<T> extends BaseAdapter {

    //适配器需要上下文，数据
    //使用ptotected修饰符，使子类也可以用
    protected Context mContext;
    protected List<T> mList;

    public ListItemAdapter(Context mContext,List<T> mList){
        this.mContext = mContext;
        this.mList = mList;
    }

    @Override
    public int getCount() {
        return mList.size();
    }

    @Override
    public T getItem(int position) {
        return mList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }
}

然后ImageAdapter只要继承ListItemAdapter重写getView即可

public class ImageAdapter extends ListItemAdapter<File> {

    private boolean select = false;

    public void open(int position){
        select = true;
        booleanArray.put(position,true);
        if(onImageCheckedListener != null){
            onImageCheckedListener.onImageChecked(true);
        }
        this.notifyDataSetChanged();
    }

    public void close(){
        select = false;
        booleanArray.clear();
        this.notifyDataSetChanged();
    }

    public ImageAdapter(Context mContext, List<File> mList) {
        super(mContext, mList);
    }

    @Override
    public int getCount() {
        //多出来的第一张为照相机，点击进入照相机
        return super.getCount()+1;
    }


    /**
     * 这里布局重用，使用checkbox会导致很多问题，
     * 勾选了一个，下拉之后发现下面也被勾选了一个
     * 这时，我们可以使用HashMap<Integer,Boolean>,是否被勾选
     *
     * 这里推荐使用另外一个类SparseBooleanArray
     *
     * @param position
     * @param convertView
     * @param parent
     * @return
     */
    SparseBooleanArray booleanArray = new SparseBooleanArray();

    public SparseBooleanArray getBooleanArray() {
        return booleanArray;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        ViewHolder viewHolder;
        if(convertView == null){
            convertView = View.inflate(mContext,R.layout.item_image,null);
            viewHolder = new ViewHolder(convertView);
            convertView.setTag(viewHolder);
        }

        viewHolder = (ViewHolder) convertView.getTag();

        if(position == 0){
            //照相机
            viewHolder.iv_img.setImageResource(R.mipmap.camera);
            viewHolder.cb_btn.setVisibility(View.GONE);
        }else{

            //设置图片
            viewHolder.iv_img.setImageURI(Uri.fromFile(mList.get(position - 1)));

            if(select) {
                viewHolder.cb_btn.setVisibility(View.VISIBLE);
                //是否需要勾选呢？
                Boolean b = booleanArray.get(position);
                if (b == null || b == false) {
                    viewHolder.cb_btn.setChecked(false);
                } else {
                    viewHolder.cb_btn.setChecked(true);
                }


                //checkbox不能设置onCheckChange监听，因为上面setChecked导致下面isCheck也会跟着变化
            /*viewHolder.cb_btn.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
                @Override
                public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                    booleanArray.put(position,isChecked);
                }
            });*/
                viewHolder.cb_btn.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        //position有可能不存在，为空，这里必须给Boolean
                        Boolean b = booleanArray.get(position);
                        if (b == null || b == false) {
                            b = true;
                        } else {
                            b = false;
                        }
                        booleanArray.put(position, b);

                        //判断所有boolean ,如果没有一个true,则关闭
                        for (int i = 0; i <booleanArray.size() ; i++) {
                            //i一定存在，所以可以给boolean
                            boolean isChecked = booleanArray.get(booleanArray.keyAt(i));
                            if(isChecked){
                                //说明有被勾选的值
                                if(onImageCheckedListener != null){
                                    onImageCheckedListener.onImageChecked(true);
                                }
                                return;
                            }
                        }
                        //没有被勾选的值，
                        if(onImageCheckedListener != null)
                            onImageCheckedListener.onImageChecked(false);
                        //关闭
                        close();
                    }
                });
            }else {
                viewHolder.cb_btn.setVisibility(View.GONE);
            }
        }
        return convertView;
    }

    //回调方法
    //写在需要执行方法的地方
    //实现，在需要返回的地方
    public interface  OnImageCheckedListener{
        void onImageChecked(boolean b);
    }

    private OnImageCheckedListener onImageCheckedListener;

    //alt + insert
    public void setOnImageCheckedListener(OnImageCheckedListener onImageCheckedListener) {
        this.onImageCheckedListener = onImageCheckedListener;
    }


    class ViewHolder{
        ImageView iv_img;
        CheckBox cb_btn;

        public ViewHolder(View convertView){

            iv_img = (ImageView) convertView.findViewById(R.id.iv_img);
            int width = mContext.getResources().getDisplayMetrics().widthPixels / 4 -2;
            RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(width,width);
            iv_img.setLayoutParams(params);
            cb_btn = (CheckBox) convertView.findViewById(R.id.cb_btn);
        }
    }
}

点击查看大图

public class ShowBigImage extends AppCompatActivity{

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ImageView img = new ImageView(this);

        File file = (File) getIntent().getSerializableExtra("img");
        img.setImageURI(Uri.fromFile(file));
        setContentView(img);
    }
}

public class MainActivity extends AppCompatActivity implements AdapterView.OnItemClickListener, AdapterView.OnItemLongClickListener, ImageAdapter.OnImageCheckedListener, View.OnClickListener {
    private static final int CAMERA_CODE = 1;
    //SD卡所有图片
    List<File> filesList = new ArrayList<>();

    ProgressDialog dialog;

    GridView gv_image;
    TextView tv_finish;
    ImageAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //加载数据
        loadData();
        //初始化视图
        initView();

    }

    private void initView() {
        gv_image = (GridView) findViewById(R.id.gv_image);
        tv_finish = (TextView) findViewById(R.id.tv_finish);
        adapter = new ImageAdapter(this,filesList);
        tv_finish.setOnClickListener(this);
        adapter.setOnImageCheckedListener(this);
        gv_image.setAdapter(adapter);
        //点击图片查看大图
        gv_image.setOnItemClickListener(this);
        //长按选择图片
        gv_image.setOnItemLongClickListener(this);
    }

    public ProgressDialog showDialog(){
        //显示Dialog
        dialog = new ProgressDialog(this);
        dialog.setTitle("加载数据");
        dialog.setMessage("正在加载数据，请稍等...");
        dialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        dialog.show();

        return dialog;
    }

    public void loadData(){
        dialog = showDialog();

        //数据加载不能阻塞UI
        //在子线程中加载
        new Thread(){
            @Override
            public void run() {
                super.run();
                //开始递归遍历SD卡根目录
                /*public static File getExternalStorageDirectory() {
                    throwIfUserRequired();
                    return sCurrentUser.getExternalDirs()[0];//获取第0张SD卡如果想要其他SD卡，只要重写这个方法即可
                }*/
                File SDDir = Environment.getExternalStorageDirectory();
                getFiles(SDDir);

                //数据加载完毕，要关闭Dialog
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        dialog.dismiss();
                        //刷新适配器
                        adapter.notifyDataSetChanged();
                    }
                });
            }
        }.start();
    }

    public void getFiles(File dir){
        File[] files = dir.listFiles();

        if(files == null){
            return;
        }

        //开始遍历
        for (File file : files) {
            if(file.isDirectory()){
                getFiles(file);
            }else{
                if(file.getName().endsWith("jpg") || file.getName().endsWith("png")){
                    filesList.add(file);
                }
            }
        }
    }

    File cameraFile;
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        //点击查看大图
        if(position == 0){
            //getAbsolutePath默认没有带"/"
            cameraFile = new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/DCIM/"+System.currentTimeMillis()+".png");
            //打开照相机
            Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            //图片保存位置
            intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(cameraFile));
            startActivityForResult(intent,CAMERA_CODE);

        }else{
            //打开大图
            File file = filesList.get(position - 1);
            //带数据点开大图
            Intent intent = new Intent(this,ShowBigImage.class);
            intent.putExtra("img",file);
            startActivity(intent);
        }

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode == requestCode && resultCode == RESULT_OK){
            //照相机的图片永远放在第一个
            filesList.add(0,cameraFile);
            adapter.notifyDataSetChanged();
        }
    }

    @Override
    public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
        //长按选择图片
        //照相机不能长按
        if(position == 0){
            return false;
        }else{
            adapter.open(position);
        }

        return true;
    }

    @Override
    public void onImageChecked(boolean b) {
        //b代表适配器中有没有被勾选的值
        tv_finish.setEnabled(b);
    }

    @Override
    public void onClick(View v) {
        //选择的图片
        //不能使用泛型，ArrayList才实现了序列化，List没有实现
        ArrayList<File> resultList = new ArrayList<>();
        //点击完成，带参返回
        //需要知道哪些数据被选中
        //通过是是适配器中的boolArray的为true的选中项来加载file
        SparseBooleanArray booleanArray = adapter.getBooleanArray();
        for (int i = 0; i <booleanArray.size() ; i++) {
            boolean isSelected = booleanArray.get(booleanArray.keyAt(i));
            if(isSelected){
                int position = booleanArray.keyAt(i);
                //剔除掉第一张照相机图片
                resultList.add(filesList.get(position-1));
            }
        }
        Intent intent = new Intent();
        intent.putExtra("list",resultList);
        //返回数据
        setResult(RESULT_OK,intent);
        finish();
    }
}

AndroidManifest.xml设置权限，注册活动

设置intent-filter <action> 并设置出口exported

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.lesson10_picselectordemo">

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

    <application android:allowBackup="true" android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name" android:supportsRtl="true" android:theme="@style/AppTheme">
        <activity android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="SelectPicture"/>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.DEFAULT"/>
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".ShowBigImage"/>
    </application>

</manifest>

测试类

点击Buttong,打开图片选择器

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.lesson10_picselectordemotest.MainActivity">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="toPicSelectorDemo"
        android:layout_centerInParent="true"
        android:text="图片选择器启动另一个Module" />
</RelativeLayout>

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void toPicSelectorDemo(View v){

         startActivityForResult(new Intent("SelectPicture"),1);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(resultCode == RESULT_OK){
            ArrayList<File> file = (ArrayList<File>) data.getSerializableExtra("list");
            Toast.makeText(this,file.toString(),Toast.LENGTH_SHORT).show();
        }
    }
}