Android BottomSheet：以选取图片为例（2）



Android BottomSheet：以选取图片为例（2）

附录文章5简单介绍了常见的分享面板在BottomSheet中的具体应用。本文再以常见的选取图片为例写一个例子。

布局文件：

<?xml version="1.0" encoding="utf-8"?>
<com.flipboard.bottomsheet.BottomSheetLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/bottomsheet"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="16dp">

        <Button
            android:id="@+id/image_picker_button"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal|top"
            android:layout_marginBottom="16dp"
            android:text="选择"
            />

        <ImageView
            android:id="@+id/image_picker_selected"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_centerInParent="true"
            android:layout_below="@id/image_picker_button"
            />

    </RelativeLayout>

</com.flipboard.bottomsheet.BottomSheetLayout>

上层Java代码：

package zhangphil.demo;

import android.Manifest;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ImageView;
import android.widget.Toast;

import com.bumptech.glide.Glide;
import com.flipboard.bottomsheet.BottomSheetLayout;
import com.flipboard.bottomsheet.commons.ImagePickerSheetView;

import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

public class MainActivity extends AppCompatActivity {

    private static final int REQUEST_STORAGE = 0;
    private static final int REQUEST_IMAGE_CAPTURE = REQUEST_STORAGE + 1;
    private static final int REQUEST_LOAD_IMAGE = REQUEST_IMAGE_CAPTURE + 1;
    protected BottomSheetLayout bottomSheetLayout;
    private Uri cameraImageUri = null;
    private ImageView selectedImage;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bottomSheetLayout = (BottomSheetLayout) findViewById(R.id.bottomsheet);
        bottomSheetLayout.setPeekOnDismiss(true);
        selectedImage = (ImageView) findViewById(R.id.image_picker_selected);
        findViewById(R.id.image_picker_button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (checkNeedsPermission()) {
                    requestStoragePermission();
                } else {
                    showSheetView();
                }
            }
        });
    }

    private boolean checkNeedsPermission() {
        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN && ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED;
    }

    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    private void requestStoragePermission() {
        if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, REQUEST_STORAGE);
        } else {
            // Eh, prompt anyway
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, REQUEST_STORAGE);
        }
    }

    @TargetApi(Build.VERSION_CODES.M)
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (requestCode == REQUEST_STORAGE) {
            if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                showSheetView();
            } else {
                // Permission denied
                Toast.makeText(this, "Sheet is useless without access to external storage :/", Toast.LENGTH_SHORT).show();
            }
        } else {
            super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }

    /**
     * Show an {@link ImagePickerSheetView}
     */
    private void showSheetView() {
        ImagePickerSheetView sheetView = new ImagePickerSheetView.Builder(this)
                .setMaxItems(30)
                .setShowCameraOption(createCameraIntent() != null)
                .setShowPickerOption(createPickIntent() != null)
                .setImageProvider(new ImagePickerSheetView.ImageProvider() {
                    @Override
                    public void onProvideImage(ImageView imageView, Uri imageUri, int size) {
                        Glide.with(MainActivity.this)
                                .load(imageUri)
                                .centerCrop()
                                .crossFade()
                                .into(imageView);
                    }
                })
                .setOnTileSelectedListener(new ImagePickerSheetView.OnTileSelectedListener() {
                    @Override
                    public void onTileSelected(ImagePickerSheetView.ImagePickerTile selectedTile) {
                        bottomSheetLayout.dismissSheet();
                        if (selectedTile.isCameraTile()) {
                            dispatchTakePictureIntent();
                        } else if (selectedTile.isPickerTile()) {
                            startActivityForResult(createPickIntent(), REQUEST_LOAD_IMAGE);
                        } else if (selectedTile.isImageTile()) {
                            showSelectedImage(selectedTile.getImageUri());
                        } else {
                            genericError();
                        }
                    }
                })
                .setTitle("选择一张照片...")
                .create();

        bottomSheetLayout.showWithSheetView(sheetView);
    }

    /**
     * For images captured from the camera, we need to create a File first to tell the camera
     * where to store the image.
     *
     * @return the File created for the image to be store under.
     */
    private File createImageFile() throws IOException {
        // Create an image file name
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(new Date());
        String imageFileName = "JPEG_" + timeStamp + "_";
        File storageDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
        File imageFile = File.createTempFile(
                imageFileName,  /* prefix */
                ".jpg",         /* suffix */
                storageDir      /* directory */
        );

        // Save a file: path for use with ACTION_VIEW intents
        cameraImageUri = Uri.fromFile(imageFile);
        return imageFile;
    }

    /**
     * This checks to see if there is a suitable activity to handle the `ACTION_PICK` intent
     * and returns it if found. {@link Intent#ACTION_PICK} is for picking an image from an external app.
     *
     * @return A prepared intent if found.
     */
    @Nullable
    private Intent createPickIntent() {
        Intent picImageIntent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
        if (picImageIntent.resolveActivity(getPackageManager()) != null) {
            return picImageIntent;
        } else {
            return null;
        }
    }

    /**
     * This checks to see if there is a suitable activity to handle the {@link MediaStore#ACTION_IMAGE_CAPTURE}
     * intent and returns it if found. {@link MediaStore#ACTION_IMAGE_CAPTURE} is for letting another app take
     * a picture from the camera and store it in a file that we specify.
     *
     * @return A prepared intent if found.
     */
    @Nullable
    private Intent createCameraIntent() {
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
            return takePictureIntent;
        } else {
            return null;
        }
    }

    /**
     * This utility function combines the camera intent creation and image file creation, and
     * ultimately fires the intent.
     *
     * @see {@link #createCameraIntent()}
     * @see {@link #createImageFile()}
     */
    private void dispatchTakePictureIntent() {
        Intent takePictureIntent = createCameraIntent();
        // Ensure that there's a camera activity to handle the intent
        if (takePictureIntent != null) {
            // Create the File where the photo should go
            try {
                File imageFile = createImageFile();
                takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(imageFile));
                startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
            } catch (IOException e) {
                // Error occurred while creating the File
                genericError("Could not create imageFile for camera");
            }
        }
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == Activity.RESULT_OK) {
            Uri selectedImage = null;
            if (requestCode == REQUEST_LOAD_IMAGE && data != null) {
                selectedImage = data.getData();
                if (selectedImage == null) {
                    genericError();
                }
            } else if (requestCode == REQUEST_IMAGE_CAPTURE) {
                // Do something with imagePath
                selectedImage = cameraImageUri;
            }

            if (selectedImage != null) {
                showSelectedImage(selectedImage);
            } else {
                genericError();
            }
        }
    }

    private void showSelectedImage(Uri selectedImageUri) {
        selectedImage.setImageDrawable(null);
        Glide.with(this)
                .load(selectedImageUri)
                .crossFade()
                .fitCenter()
                .into(selectedImage);
    }

    private void genericError() {
        genericError(null);
    }

    private void genericError(String message) {
        Toast.makeText(this, message == null ? "Something went wrong." : message, Toast.LENGTH_SHORT).show();
    }

}

由于需要读取设备图象文件，须增加权限：

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

本例中在加载图片时候使用了Glide，关于Glide，请查阅附录文章4。

代码运行结果--->

初始化状态：

点击button按钮弹出选择面板：

拖曳向上铺满窗口：

本例中的照片选取代码是一个相对比较独立、可以单独抽取出去的通用模块化代码，支持从图库中选取，也支持调用相机拍照出图，在其他项目中使用，只需要关注诸如本例中的button按钮事件以及最终的图片加载位置，就可以在自己的项目灵活使用。

附录文章：

1，《Android自底部平滑向上滑出面板的AndroidSlidingUpPanel》链接地址：http://blog.csdn.net/zhangphil/article/details/51444509


2，《Android音乐、视频类APP常用控件：DraggablePanel（1）》链接地址：http://blog.csdn.net/zhangphil/article/details/51566860 


3，《Android音乐、视频类APP常用控件：DraggablePanel（2）》链接地址：http://blog.csdn.net/zhangphil/article/details/51578665

4，《Android图片加载与缓存开源框架：Android Glide》链接地址http://blog.csdn.net/zhangphil/article/details/45535693 ：

5，《Android BottomSheet：便捷易用的底部滑出面板（1）》链接地址：http://blog.csdn.net/zhangphil/article/details/51775955