超简单图片浏览器

首先展示一下简单的效果

就是这样

1、manifest清单文件中的授权，获取读写权限，展示手机(模拟器)中所有的图片

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

build.gradle中Glide版本

implementation 'com.github.bumptech.glide:glide:4.5.0'

2、xml布局

<?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"
    tools:context=".MainActivity"
    android:orientation="vertical"
    android:padding="10dp">

    <Button
        android:id="@+id/button_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="查看图片"
        android:background="@android:color/holo_blue_bright"/>

    <GridView
        android:id="@+id/gv_id"
        android:numColumns="4"
        android:gravity="center"

        android:horizontalSpacing="5dp"
        android:verticalSpacing="20dp"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    </GridView>

</LinearLayout>

布局样式

3、网格布局显示图片的布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/im_id"
        android:layout_width="100dp"
        android:layout_height="100dp" />

</LinearLayout>

4、弹框布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

5、MainActivity中的方法

public class MainActivity extends AppCompatActivity {

    private Button button;
    private List<String> names = new ArrayList<String>();
    private List<String> descs = new ArrayList<String>();
    private List<String> fileNames = new ArrayList<String>();
    private GridView gvId;
    private Handler handler = new Handler();

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

        button = findViewById(R.id.button_1);
        gvId = findViewById(R.id.gv_id);
        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View arg0) {
                requestPermissions(new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE},100);
            }
        });

        gvId.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
                // 加载view.xml文件布局代表的视图
                final View view = getLayoutInflater().inflate(R.layout.img_view_itme, null);
                // 获取图片组件
                ImageView image = (ImageView) view.findViewById(R.id.imageView1);
                image.setImageBitmap(BitmapFactory.decodeFile(fileNames.get(arg2)));
//                AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
//                builder.setView(view);
//
//                AlertDialog alertDialog = builder.create();
//                alertDialog.show();
                final ProgressDialog dialog = new ProgressDialog(MainActivity.this);
                dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
                dialog.setMax(100);
                dialog.setMessage("加载中...");
                dialog.show();//显示
                //闲着没事模拟一个进度条
                final Timer timer = new Timer();
                timer.schedule(new TimerTask() {
                    int progress = 0;
                    @Override
                    public void run() {
                        if (progress >= 100){
                            dialog.dismiss();
                            timer.cancel();
                            handler.post(new Runnable() {
                                @Override
                                public void run() {
                                    AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
                                    builder.setView(view).setCancelable(true);
                                    //使用建造者创建对话框
                                    AlertDialog dialog = builder.create();
                                    dialog.show();
                                }
                            });
                        }
                        dialog.setProgress(progress += 2);
                    }
                },0,10);

            }
        });
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == 100 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
            allPic();
        }
    }

    private void allPic() {

        names.clear();
        descs.clear();
        fileNames.clear();
        // 通过ContentProvider查询所有的图片信息
        Cursor cursor = getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                null, null, null, null);
        while (cursor.moveToNext()) {
            // 获取图片的显示名
            String name = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DISPLAY_NAME));
            String desc = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DESCRIPTION));
            byte[] data = cursor.getBlob(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
            // 将图片描述添加到集合中
            descs.add(desc);
            names.add(name);
            fileNames.add(new String(data, 0, data.length - 1));
        }

        gvId.setAdapter(new MyAdapter());

    }
    class MyAdapter extends BaseAdapter {
        @Override
        public int getCount() {
            return fileNames.size();
        }

        @Override
        public Object getItem(int position) {
            return null;
        }

        @Override
        public long getItemId(int position) {
            return 0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder viewHolder;
            if(convertView == null){
                convertView = LayoutInflater.from(MainActivity.this).inflate(R.layout.image_layout,parent,false);
                viewHolder = new ViewHolder();
                viewHolder.imageView = convertView.findViewById(R.id.im_id);
                convertView.setTag(viewHolder);
            }else{
                viewHolder = (ViewHolder) convertView.getTag();
            }
            String s = fileNames.get(position);
            Glide.with(MainActivity.this).load(s).into(viewHolder.imageView);
            return convertView;
        }
        class ViewHolder{
            ImageView imageView;
        }
    }
}