选取相册图片并显示

电玩女神 2022-08-28 11:39 262阅读 0赞

下面这些功能都需要在Activity中实现，如果在fragment中，则

//Fragment中调用activity方法
    MainActivity activity=(MainActivity)getActivity();
    activity.openPhotoAlbum();

主要是访问权限和数据转换

1 访问权限

在Manifest中授权

<uses-feature
            android:name="android.hardware.camera"
            android:required="true"
            />
    
        <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
        <uses-permission android:name="android.permission.CAMERA"/>
        <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"
            tools:ignore="ProtectedPermissions" />
        <uses-permission android:name="com.sichuanwww.showpic.permission.ACCESS_PROVIDER"/>
        <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
        <uses-feature android:name="android.hardware.camera.autofocus" />

在代码中也需要动态授权

2 基本布局

一个ImageView 一个textView 一个button

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        tools:context=".MainActivity">
    
        <ImageView
                android:id="@+id/imageView"
                android:layout_width="wrap_content"
                android:layout_height="0dp"
                android:layout_weight="4"
                tools:srcCompat="@mipmap/ic_launcher" />
    
            <TextView
                android:id="@+id/txt"
            android:layout_width="wrap_content"
            android:layout_height="0dp"
                android:layout_weight="4"
            android:text="Hello wwwww"      />
    
            <Button
                android:id="@+id/button"
                android:layout_width="wrap_content"
                android:layout_height="0dp"
                android:layout_weight="4"
                android:text="PhotoAlbum" />
    
    </LinearLayout>

3 功能代码

package com.sichuanwww.showpic;
    
    import android.Manifest;
    import android.app.Activity;
    import android.content.Intent;
    import android.content.pm.PackageManager;
    import android.os.Build;
    import android.os.Bundle;
    import android.provider.MediaStore;
    import android.support.annotation.NonNull;
    import android.support.v4.app.ActivityCompat;
    import android.support.v7.app.AppCompatActivity;
    import android.view.View;
    import android.widget.Button;
    import android.widget.ImageView;
    import android.widget.TextView;
    import android.widget.Toast;
    
    public class MainActivity extends AppCompatActivity {
    
        String[] mPermissionList = new String[]{
                Manifest.permission.WRITE_EXTERNAL_STORAGE,
                Manifest.permission.READ_EXTERNAL_STORAGE};
        public static final int REQUEST_PICK_IMAGE = 11101;
        private ImageView mShowImg;
        private TextView  tx;
        private Button bt;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            mShowImg = (ImageView) findViewById(R.id.imageView);
            tx = (TextView) findViewById(R.id.txt);
            bt=(Button) findViewById(R.id.button);
    
            mShowImg.setImageResource(R.mipmap.ic_launcher);
            bt.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
    
                    /*
                    //函数调用顺序： openPhotoAlbum              >>
                                    onRequestPermissionsResult  >>
                                    getImage                    >>
                                    onActivityResult            >>
                    */
    
                    openPhotoAlbum();
                }
            });
    
        }
    
        @Override
        public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
            super.onRequestPermissionsResult(requestCode, permissions, grantResults);
            switch (requestCode) {
                case 100:
                    boolean writeExternalStorage = grantResults[0] == PackageManager.PERMISSION_GRANTED;
                    boolean readExternalStorage = grantResults[1] == PackageManager.PERMISSION_GRANTED;
    
                    if (grantResults.length > 0 && writeExternalStorage && readExternalStorage) {
                        getImage();
                    } else {
                        Toast.makeText(this, "请设置必要权限", Toast.LENGTH_SHORT).show();
                    }
    
                    break;
            }
        }
    
        private void getImage() {
            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {
                startActivityForResult(new Intent(Intent.ACTION_GET_CONTENT).setType("image/*"),
                        REQUEST_PICK_IMAGE);
            } else {
                Intent intent = new Intent(Intent.ACTION_PICK, null);
                intent.setDataAndType(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, "image/*");
                startActivityForResult(intent, REQUEST_PICK_IMAGE);
            }
        }
    
        @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
            if (resultCode == Activity.RESULT_OK) {
                switch (requestCode) {
                    case REQUEST_PICK_IMAGE:
                        if (data != null) {
                            String realPathFromUri = RealPathFromUriUtils.getRealPathFromUri(this, data.getData());
                            tx.setText(realPathFromUri);
                            mShowImg.setImageURI(data.getData());
                        } else {
                            Toast.makeText(this, "图片损坏，请重新选择", Toast.LENGTH_SHORT).show();
                        }
                        break;
                }
            }
        }
        //打开相册
        public void openPhotoAlbum() {
            ActivityCompat.requestPermissions(MainActivity.this, mPermissionList, 100);
        }
    
    
    
    }

代码本身很简单，只是有很多坑。

4 获取图片真实路径代码

如果只是显示，则可以不用，只是需要上传文件时使用

package com.sichuanwww.showpic;
    import android.annotation.SuppressLint;
    import android.content.ContentUris;
    import android.content.Context;
    import android.database.Cursor;
    import android.net.Uri;
    import android.os.Build;
    import android.provider.DocumentsContract;
    import android.provider.MediaStore;
    
    public class RealPathFromUriUtils {
        /**
         * 根据Uri获取图片的绝对路径
         *
         * @param context 上下文对象
         * @param uri   图片的Uri
         * @return 如果Uri对应的图片存在, 那么返回该图片的绝对路径, 否则返回null
         */
        public static String getRealPathFromUri(Context context, Uri uri) {
            int sdkVersion = Build.VERSION.SDK_INT;
            if (sdkVersion >= 19) { // api >= 19
                return getRealPathFromUriAboveApi19(context, uri);
            } else { // api < 19
                return getRealPathFromUriBelowAPI19(context, uri);
            }
        }
    
        /**
         * 适配api19以下(不包括api19),根据uri获取图片的绝对路径
         *
         * @param context 上下文对象
         * @param uri   图片的Uri
         * @return 如果Uri对应的图片存在, 那么返回该图片的绝对路径, 否则返回null
         */
        private static String getRealPathFromUriBelowAPI19(Context context, Uri uri) {
            return getDataColumn(context, uri, null, null);
        }
    
        /**
         * 适配api19及以上,根据uri获取图片的绝对路径
         *
         * @param context 上下文对象
         * @param uri   图片的Uri
         * @return 如果Uri对应的图片存在, 那么返回该图片的绝对路径, 否则返回null
         */
        @SuppressLint("NewApi")
        private static String getRealPathFromUriAboveApi19(Context context, Uri uri) {
            String filePath = null;
            if (DocumentsContract.isDocumentUri(context, uri)) {
                // 如果是document类型的 uri, 则通过document id来进行处理
                String documentId = DocumentsContract.getDocumentId(uri);
                if (isMediaDocument(uri)) { // MediaProvider
                    // 使用':'分割
                    String id = documentId.split(":")[1];
    
                    String selection = MediaStore.Images.Media._ID + "=?";
                    String[] selectionArgs = {id};
                    filePath = getDataColumn(context, MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection, selectionArgs);
                } else if (isDownloadsDocument(uri)) { // DownloadsProvider
                    Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(documentId));
                    filePath = getDataColumn(context, contentUri, null, null);
                }
            } else if ("content".equalsIgnoreCase(uri.getScheme())) {
                // 如果是 content 类型的 Uri
                filePath = getDataColumn(context, uri, null, null);
            } else if ("file".equals(uri.getScheme())) {
                // 如果是 file 类型的 Uri,直接获取图片对应的路径
                filePath = uri.getPath();
            }
            return filePath;
        }
    
        /**
         * 获取数据库表中的 _data 列，即返回Uri对应的文件路径
         *
         * @return
         */
        private static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) {
            String path = null;
    
            String[] projection = new String[]{MediaStore.Images.Media.DATA};
            Cursor cursor = null;
            try {
                cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);
                if (cursor != null && cursor.moveToFirst()) {
                    int columnIndex = cursor.getColumnIndexOrThrow(projection[0]);
                    path = cursor.getString(columnIndex);
                }
            } catch (Exception e) {
                if (cursor != null) {
                    cursor.close();
                }
            }
            return path;
        }
    
        /**
         * @param uri the Uri to check
         * @return Whether the Uri authority is MediaProvider
         */
        private static boolean isMediaDocument(Uri uri) {
            return "com.android.providers.media.documents".equals(uri.getAuthority());
        }
    
        /**
         * @param uri the Uri to check
         * @return Whether the Uri authority is DownloadsProvider
         */
        private static boolean isDownloadsDocument(Uri uri) {
            return "com.android.providers.downloads.documents".equals(uri.getAuthority());
        }
    }