android 13 LoaderManager AsyncTaskLoader读取手机图片，Java

短命女 2023-09-25 17:18 31阅读 0赞

android 13 LoaderManager AsyncTaskLoader读取手机图片 ，Java

权限：

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

package zhangphil.app;
    
    import androidx.annotation.NonNull;
    import androidx.annotation.Nullable;
    import androidx.appcompat.app.AppCompatActivity;
    import androidx.loader.app.LoaderManager;
    import androidx.loader.content.AsyncTaskLoader;
    import androidx.loader.content.Loader;
    
    import android.content.Context;
    import android.database.Cursor;
    import android.os.Bundle;
    import android.provider.MediaStore;
    import android.util.Log;
    
    import java.io.File;
    import java.text.SimpleDateFormat;
    import java.util.ArrayList;
    import java.util.Date;
    import java.util.List;
    
    public class MainActivity extends AppCompatActivity {
        private static String TAG = "fly";
    
        private LoaderManager loaderManager;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
    
            setupLoader();
        }
    
        private static class Photo {
            private String name;//名称
            private String date;//日期
            private long size;  //大小
            private String path;//路径
    
    
            public Photo(String name, String date, long size, String path) {
                this.name = name;
                this.date = date;
                this.size = size;
                this.path = path;
            }
        }
    
        private static List<Photo> readImage(Context context) {
            List<Photo> photoList = new ArrayList<>();
    
            //读取手机图片
            Cursor cursor = context.getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
            while (cursor.moveToNext()) {
                //图片的路径
                String path = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA));
    
                //图片名称
                String name = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DISPLAY_NAME));
    
                //图片最后修改日期
                //String date_modified = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATE_MODIFIED));
                File file = new File(path);
                SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
                String date = sdf.format(new Date(file.lastModified()));
    
                //图片大小
                long size = cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.SIZE));
                Photo photo = new Photo(name, date, size, path);
    
                photoList.add(photo);
            }
    
            return photoList;
        }
    
        private void setupLoader() {
            loaderManager = LoaderManager.getInstance(this);
            loaderManager.initLoader(2023, new Bundle(), loaderCallbacks);
        }
    
        private LoaderManager.LoaderCallbacks loaderCallbacks = new LoaderManager.LoaderCallbacks<List<Photo>>() {
            @NonNull
            @Override
            public MyLoader onCreateLoader(int id, @Nullable Bundle args) {
                Log.d(TAG, "onCreateLoader- id - " + id);
                MyLoader loader = new MyLoader(getApplicationContext());
                return loader;
            }
    
            @Override
            public void onLoadFinished(@NonNull Loader<List<Photo>> loader, List<Photo> photos) {
                Log.d(TAG, "onLoadFinished- " + loader.getId() + " - " + photos);
                for (Photo p : photos) {
                    Log.d(TAG, p.name + " " + p.date + " " + p.size + " " + p.path);
                }
            }
    
            @Override
            public void onLoaderReset(@NonNull Loader loader) {
    
            }
        };
    
        @Override
        protected void onStart() {
            super.onStart();
            Log.d(TAG, "---");
            Log.d(TAG, "onStart");
        }
    
        @Override
        protected void onResume() {
            super.onResume();
            Log.d(TAG, "onResume");
        }
    
        @Override
        protected void onStop() {
            super.onStop();
            Log.d(TAG, "onStop");
        }
    
        private static class MyLoader extends AsyncTaskLoader<List<Photo>> {
            private Context context;
    
            public MyLoader(@NonNull Context context) {
                super(context);
                this.context = context;
            }
    
            @Override
            protected void onStartLoading() {
                super.onStartLoading();
                Log.d(TAG, "onStartLoading- " + getId());
    
                this.forceLoad();
            }
    
            //work thread
            @Nullable
            @Override
            public List<Photo> loadInBackground() {
                return readImage(context);
            }
    
            //UI main thread
            @Override
            public void deliverResult(@Nullable List<Photo> photos) {
                super.deliverResult(photos);
                Log.d(TAG, "deliverResult- " + getId() + " 图片总量:" + photos.size());
            }
    
            @Override
            public void onContentChanged() {
                super.onContentChanged();
                Log.d(TAG, "onContentChanged- " + getId());
            }
        }
    }

[android 13读取本机所有图片名和存储绝对路径，Java\_zhangphil的博客-CSDN博客【Android设置头像，手机拍照或从本地相册选取图片作为头像】像微信、QQ、微博等社交类的APP，通常都有设置头像的功能，设置头像通常有两种方式：1，让用户通过选择本地相册之类的图片库中已有的图像，裁剪后作为头像。Android设置头像，手机拍照或从本地相册选取图片作为头像\_android 头像拍照\_zhangphil的博客-CSDN博客。Android图片添加文字水印并保存水印文字图片到指定文件\_zhangphil的博客-CSDN博客。![favicon32.ico][]https://blog.csdn.net/zhangphil/article/details/129639271][android 13_Java_zhangphil_-CSDN_Android_QQ_APP_1_Android_android _zhangphil_-CSDN_Android_zhangphil_-CSDN_favicon32.ico_https_blog.csdn.net_zhangphil_article_details_129639271]

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