Android photo selection interface

package cc.vv.btongbaselibrary.ui.view.imagepicker;

import android.Manifest;
import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ObjectAnimator;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.graphics.Color;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.provider.Settings;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.SimpleItemAnimator;
import android.view.KeyEvent;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.FrameLayout;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;

import cc.vv.btongbaselibrary.R;
import cc.vv.btongbaselibrary.ui.view.imagepicker.adapter.FolderAdapter;
import cc.vv.btongbaselibrary.ui.view.imagepicker.adapter.ImageAdapter;
import cc.vv.btongbaselibrary.ui.view.imagepicker.entry.FolderObj;
import cc.vv.btongbaselibrary.ui.view.imagepicker.entry.ImageObj;
import cc.vv.btongbaselibrary.ui.view.imagepicker.model.ImageModel;
import cc.vv.btongbaselibrary.vFinal.BTResultCode;

/**
 * 图片选择界面
 *
 * @author Zml
 */
public class ImageSelectorActivity extends AppCompatActivity {

    public static final String KEY_MAX_SELECT_COUNT = "max_select_count";
    public static final String KEY_IS_SINGLE = "is_single";
    private static final String KEY_SELECTED = "selected";

    private TextView tvFolderName;
    private TextView tvConfirm;
    private TextView tvPreview;
    private FrameLayout btnConfirm;
    private FrameLayout btnPreview;
    private RecyclerView rvImage;
    private RecyclerView rvFolder;
    private View masking;
    private ImageAdapter mAdapter;
    private GridLayoutManager mLayoutManager;
    private ArrayList<FolderObj> mFolders;
    private FolderObj mFolder;
    private boolean isToSettings = false;
    private static final int PERMISSION_REQUEST_CODE = 0X0011;

    private boolean isOpenFolder;
    private boolean isInitFolder;
    private boolean isSingle; 
    private int mMaxCount; 

    /** 
     * Used to receive a list of selected images from outside. When the user has already selected a picture, and now reopen the selector, 
     * allows the user to pass in the pictures previously selected, and these pictures are selected as the default state. 
     */ 
    private ArrayList<String> mSelectedImages; 

    /** 
     * Start the image selector 
     * 
     * @param activity 
     * @param requestCode 
     * @param isSingle Whether single selection 
     * @param maxSelectCount The maximum number of images to select, if less than or equal to 0, unlimited Quantity, only useful when isSingle is false. 
     * @param selected Receive a list of selected images passed in from outside. When the user has already selected a picture, now reopen the 
     * selector, allowing the user to pass in the previously selected pictures, and these pictures will be selected by default. 
     */ 
    public static void openActivity(Activity activity, int requestCode,
                                    boolean isSingle, int maxSelectCount, ArrayList<String> selected) {
        Intent intent = new Intent(activity, ImageSelectorActivity.class);
        intent.putExtra(KEY_MAX_SELECT_COUNT, maxSelectCount);
        intent.putExtra(KEY_IS_SINGLE, isSingle);
        intent.putStringArrayListExtra(KEY_SELECTED, selected);
        activity.startActivityForResult(intent, requestCode);
    }

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

        Intent intent = getIntent();
        mMaxCount = intent.getIntExtra(KEY_MAX_SELECT_COUNT, 0);
        isSingle = intent.getBooleanExtra(KEY_IS_SINGLE, false);
        mSelectedImages = intent.getStringArrayListExtra(KEY_SELECTED);

        setStatusBarColor();
        initView();
        initListener();
        initImageList();
        checkPermissionAndLoadImages();
        hideFolderList();
        setSelectImageCount(0);
    }

    /**
     * 修改状态栏颜色
     */
    private void setStatusBarColor() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            Window window = getWindow();
            window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            window.setStatusBarColor(Color.parseColor("#373c3d"));
        }
    }

    private void initView() {
        rvImage = findViewById(R.id.rv_image);
        rvFolder = findViewById(R.id.rv_folder);
        tvConfirm = findViewById(R.id.tv_confirm);
        tvPreview = findViewById(R.id.tv_preview);
        btnConfirm = findViewById(R.id.btn_confirm);
        btnPreview = findViewById(R.id.btn_preview);
        tvFolderName = findViewById(R.id.tv_folder_name);
        masking = findViewById(R.id.masking);
    }

    private void initListener() {
        findViewById(R.id.btn_back).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
            }
        });

        btnPreview.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ArrayList<ImageObj> images = new ArrayList<>();
                images.addAll(mAdapter.getSelectImages());
                toPreviewActivity(images, 0);
            }
        });

        btnConfirm.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                confirm();
            }
        });

        findViewById(R.id.btn_folder).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (isInitFolder) {
                    if (isOpenFolder) {
                        closeFolder();
                    } else {
                        openFolder();
                    }
                }
            }
        });

        masking.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                closeFolder();
            }
        });
    }

    /**
     * 初始化图片列表
     */
    private void initImageList() {
        // 判断屏幕方向
        Configuration configuration = getResources().getConfiguration();
        if (configuration.orientation == Configuration.ORIENTATION_PORTRAIT) {
            mLayoutManager = new GridLayoutManager(this, 3);
        } else {
            mLayoutManager = new GridLayoutManager(this, 5);
        }

        rvImage.setLayoutManager(mLayoutManager);
        mAdapter = new ImageAdapter(this, mMaxCount, isSingle);
        rvImage.setAdapter(mAdapter);
        ((SimpleItemAnimator) rvImage.getItemAnimator()).setSupportsChangeAnimations(false);
        if (mFolders != null && !mFolders.isEmpty()) {
            setFolder(mFolders.get(0));
        }
        mAdapter.setOnImageSelectListener(new ImageAdapter.OnImageSelectListener() {
            @Override
            public void OnImageSelect(ImageObj image, boolean isSelect, int selectCount) {
                setSelectImageCount(selectCount);
            }
        });
        mAdapter.setOnItemClickListener(new ImageAdapter.OnItemClickListener() {
            @Override
            public void OnItemClick(ImageObj image, int position) {
                toPreviewActivity(mAdapter.getData(), position);
            }
        });
    }

    /**
     * 初始化图片文件夹列表
     */
    private void initFolderList() {
        if (mFolders != null && !mFolders.isEmpty()) {
            isInitFolder = true;
            rvFolder.setLayoutManager(new LinearLayoutManager(ImageSelectorActivity.this));
            FolderAdapter adapter = new FolderAdapter(ImageSelectorActivity.this, mFolders);
            adapter.setOnFolderSelectListener(new FolderAdapter.OnFolderSelectListener() {
                @Override
                public void OnFolderSelect(FolderObj folder) {
                    setFolder(folder);
                    closeFolder(); 
                } 
            }); 
            rvFolder.setAdapter(adapter); 
        } 
    } 

    /** 
     * The folder list is hidden by default at the beginning 
     */ 
    private void hideFolderList() { 
        rvFolder.post(new Runnable() { 
            @ Override 
            public void run() { 
                rvFolder.setTranslationY(rvFolder.getHeight()); 
                rvFolder.setVisibility(View.GONE); 
            } 
        }); 
    } 

    /** 
     * Set the selected folder and refresh the picture list at the same time 
     * 
     * @param folder 
     */ 
    private void setFolder(FolderObj folder) {
        if (folder != null && mAdapter != null && !folder.equals(mFolder)) {
            mFolder = folder;
            tvFolderName.setText(folder.getName());
            rvImage.scrollToPosition(0);
            mAdapter.refresh(folder.getImages());
        }
    }

    private void setSelectImageCount(int count) {
        if (count == 0) {
            btnConfirm.setEnabled(false);
            btnPreview.setEnabled(false);
            tvConfirm.setText("确定");
            tvPreview.setText("预览");
        } else {
            btnConfirm.setEnabled(true);
            btnPreview.setEnabled(true);
            tvPreview.setText("预览("+ count + ")");
            if (isSingle) {
                tvConfirm.setText("确定");
            } else if (mMaxCount > 0) {
                tvConfirm.setText("确定(" + count + "/" + mMaxCount + ")");
            } else {
                tvConfirm.setText("确定(" + count + ")");
            }
        }
    }

    /**
     * 弹出文件夹列表
     */
    private void openFolder() {
        if (!isOpenFolder) {
            masking.setVisibility(View.VISIBLE);
            ObjectAnimator animator = ObjectAnimator.ofFloat(rvFolder, "translationY",
                    rvFolder.getHeight(), 0).setDuration(300);
            animator.addListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationStart(Animator animation) {
                    super.onAnimationStart(animation);
                    rvFolder.setVisibility(View.VISIBLE);
                }
            });
            animator.start();
            isOpenFolder = true;
        }
    }

    /**
     * 收起文件夹列表
     */
    private void closeFolder() {
        if (isOpenFolder) {
            masking.setVisibility(View.GONE);
            ObjectAnimator animator = ObjectAnimator.ofFloat(rvFolder, "translationY",
                    0, rvFolder.getHeight()).setDuration(300); 
            animator.addListener(new AnimatorListenerAdapter() { 
                @Override 
                public void onAnimationEnd(Animator animation) { 
                    super.onAnimationEnd(animation); 
                    rvFolder.setVisibility(View.GONE); 
                } 
            }); 
            animator.start(); 
            isOpenFolder = false; 
        } 
    } 

    private void confirm() { 
        if (mAdapter == null) { 
            return; 
        } 
        //Because the entity class of the picture is Image, and we return a String array, So to convert.
        ArrayList<ImageObj> selectImages = mAdapter.getSelectImages();
        ArrayList<String> images = new ArrayList<>();
        for (ImageObj image : selectImages) {
            images.add(image.getPath());
        }

        //点击确定，把选中的图片通过Intent传给上一个Activity。
        Intent intent = new Intent();
        intent.putStringArrayListExtra(ImageGalleryUtil.SELECT_RESULT, images);
        setResult(BTResultCode.ImageSelectorActivity_RESULT_CODE, intent);
        finish();
    }

    private void toPreviewActivity(ArrayList<ImageObj> images, int position) {
        if (images != null && !images.isEmpty()) {
            PreviewActivity.openActivity(this, images,
                    mAdapter.getSelectImages(), isSingle, mMaxCount, position);
        }
    }

    @Override
    protected void onStart() {
        super.onStart();
        if (isToSettings) {
            isToSettings = false;
            checkPermissionAndLoadImages();
        }
    }

    /**
     * 处理图片预览页返回的结果
     *
     * @param requestCode
     * @param resultCode
     * @param data
     */
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == PreviewActivity.REQUEST_CODE) { 
            if (data != null && data.getBooleanExtra(PreviewActivity.KEY_IS_CONFIRM, false)) { 
                //If the user clicks OK on the preview page, directly return the image selected by the user to the user . 
                confirm(); 
            } else { 
                //Otherwise, refresh the current page. 
                mAdapter.notifyDataSetChanged(); 
                setSelectImageCount(mAdapter.getSelectImages().size()); 
            } 
        } 
    } 

    /** 
     * Horizontal and vertical screen switching processing 
     * 
     * @param newConfig 
     */ 
    @Override 
    public void onConfigurationChanged(Configuration newConfig) { 
        super.onConfigurationChanged (newConfig);
        if (mLayoutManager != null && mAdapter != null) { 
            //Switch to portrait 
            if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT) { 
                mLayoutManager.setSpanCount(3); 
            } 
            //Switch to landscape 
            else if (newConfig. orientation == Configuration.ORIENTATION_LANDSCAPE) { 
                mLayoutManager.setSpanCount(5); 
            } 
            mAdapter.notifyDataSetChanged(); 
        } 
    } 

    /** 
     * Check permissions and load images from SD card. 
     */ 
    private void checkPermissionAndLoadImages() { 
        if (!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            Toast.makeText(this, "No picture", Toast.LENGTH_LONG).show(); 
            return; 
        } 
        int hasWriteContactsPermission = ContextCompat.checkSelfPermission(getApplication(), 
                Manifest.permission.WRITE_EXTERNAL_STORAGE); 
        if (hasWriteContactsPermission == PackageManager.PERMISSION_GRANTED) { 
            //Have permission to load images. 
            loadImageForSDCard(); 
        } else { 
            //No permission, apply for permission. 
            ActivityCompat.requestPermissions(ImageSelectorActivity.this, 
                    new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, PERMISSION_REQUEST_CODE); 
        } 
    } 

    /** 
     * Callback for processing permission request.
     * 
     * @param requestCode 
     * @param permissions 
     * @param grantResults 
     */ 
    @Override 
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) { 
        if (requestCode == PERMISSION_REQUEST_CODE) { 
            if (grantResults.length > 0 
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) { 
                //Allow permission, load image. 
                loadImageForSDCard(); 
            } else { 
                //Permission denied, a prompt box pops up. 
                showExceptionDialog(); 
            } 
        } 
    } 

    /** 
     * When an exception such as no permission occurs, display a prompt dialog.
     */ 
    private void showExceptionDialog() { 
        new AlertDialog.Builder(this) 
                .setCancelable(false) 
                .setTitle("Prompt") 
                .setMessage("The album needs to be given permission to access storage, please go to "Settings" > "Apps" > Configure permissions in "Permissions".") 
                .setNegativeButton("Cancel", new DialogInterface.OnClickListener() { 
                    @Override 
                    public void onClick(DialogInterface dialog, int which) { 
                        dialog.cancel(); 
                        finish(); 
                    } 
                }). setPositiveButton("OK", new DialogInterface.OnClickListener() { 
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
                startAppSettings();
                isToSettings = true;
            }
        }).show();
    }

    /**
     * 从SDCard加载图片。
     */
    private void loadImageForSDCard() {
        ImageModel.loadImageForSDCard(this, new ImageModel.DataCallback() {
            @Override
            public void onSuccess(ArrayList<FolderObj> folders) {
                mFolders = folders;
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        if (mFolders != null && !mFolders.isEmpty()) {
                            initFolderList();
                            setFolder(mFolders.get(0));
                            if (mSelectedImages != null && mAdapter != null) {
                                mAdapter.setSelectedImages(mSelectedImages);
                                mSelectedImages = null;
                            }
                        }
                    }
                });
            }
        });
    }

    /**
     * 启动应用的设置
     */
    private void startAppSettings() {
        Intent intent = new Intent(
                Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
        intent.setData(Uri.parse("package:" + getPackageName()));
        startActivity(intent);
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN && isOpenFolder) {
            closeFolder();
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }
}