javascript - 捕获图像后网格视图不会自动刷新

Question

我尝试创建一个应用程序来捕获图像并保存到特定文件夹，它会在网格视图中显示拍摄的照片。但是在捕获图像后，它不会立即反映在网格视图中，而是在进行下一次捕获后它会更新。请帮助在捕获后立即更新网格视图中的捕获图像。还请帮助，如何将捕获的图像大小限制为最大 300 kb 大小，应保存在特定文件夹中。

package com.example.surveyassist;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.FileProvider;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.GridView;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.List;

public class CaptureActivity extends AppCompatActivity {

private static final int IMAGE_REQUEST = 1;
private DateFormat dateFormata = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String currentImagePath =null;

final int CAMERA_CAPTURE = 1;
private GridView grid;
private List<String> listOfImagesPath;

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

    grid = ( GridView) findViewById(R.id.gridviewimg);
    listOfImagesPath = null;
    listOfImagesPath = RetriveCapturedImagePath();
    if(listOfImagesPath!=null) {
        grid.setAdapter(new ImageListAdapter(this, listOfImagesPath));
    }
    nxtbuttonset();
}

public void captureImage(View view) {
    Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    if (cameraIntent.resolveActivity(getPackageManager())!=null)
    {
        File imageFile = null;
        try {
            imageFile = getImageFile();
        } catch (IOException e) {
            e.printStackTrace();
        }
        if (imageFile !=null)
        {
            Uri imageUri = FileProvider.getUriForFile(this, "com.example.surveyassist.fileprovider", imageFile);
            cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
            startActivityForResult(cameraIntent, IMAGE_REQUEST);
        }


    }


}

private File getImageFile() throws IOException {

    final String folderpath = getIntent().getExtras().getString("key");

    String timeStamp = dateFormata.format(new Date());
    String imageName = timeStamp;

    String _path = folderpath +File.separator + timeStamp+".jpg";


    File imageFile = new File (_path);
    currentImagePath=imageFile.getAbsolutePath();
    return imageFile;

}

public void nxtbuttonset() {

    Button buttonnext = (Button) findViewById(R.id.buttonNexta);

    buttonnext.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
             // Intent intenta = new Intent(CaptureActivity.this, ZipActivity.class);
              //startActivity(intenta);
            moveTaskToBack(true);
            android.os.Process.killProcess(android.os.Process.myPid());
            System.exit(1);
        }
    });
}

//user is returning from capturing an image using the camera\

public void retrive() {
    Bitmap bitmap = null;
    final String folderpath = getIntent().getExtras().getString("key");

    String timeStamp = dateFormata.format(new Date());
    String imageName = timeStamp;

    String _path = folderpath + File.separator + timeStamp + ".jpg";
    File f = new File(_path);
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inPreferredConfig = Bitmap.Config.ARGB_8888;
    try {
        bitmap = BitmapFactory.decodeStream(new FileInputStream(f), null, options);
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }

    try {
        FileOutputStream out = new FileOutputStream(_path);
        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);
        out.close();
    } catch (FileNotFoundException e) {
        e.getMessage();
    } catch (IOException e) {
        e.printStackTrace();
    }
    listOfImagesPath = null;
    listOfImagesPath = RetriveCapturedImagePath();
    if (listOfImagesPath != null) {
        grid.setAdapter(new ImageListAdapter(this, listOfImagesPath));
    }


}
private List<String> RetriveCapturedImagePath() {

    final String folderpath = getIntent().getExtras().getString("key");
    List<String> tFileList = new ArrayList<String>();
    File f = new File(folderpath);
    if (f.exists()) {
        File[] files=f.listFiles();
        Arrays.sort(files);
        for(int i=0; i<files.length; i++){
            File file = files[i];
            if(file.isDirectory())
                continue;
            tFileList.add(file.getPath());
        }
    }
    return tFileList;
}
public class ImageListAdapter extends BaseAdapter
{
    private Context context;
    private List<String> imgPic;
    public ImageListAdapter(Context c, List<String> thePic)
    {
        context = c;
        imgPic = thePic;
    }
    public int getCount() {
        if(imgPic != null)
            return imgPic.size();
        else
            return 0;
    }
    //—returns the ID of an item—
    public Object getItem(int position) {
        return position;
    }
    public long getItemId(int position) {
        return position;
    }
    //—returns an ImageView view—
    public View getView(int position, View convertView, ViewGroup parent)
    {
        ImageView imageView;
        BitmapFactory.Options bfOptions=new BitmapFactory.Options();
        bfOptions.inDither=false;                     //Disable Dithering mode
        bfOptions.inPurgeable=true;                   //Tell to gc that whether it needs free memory, the Bitmap can be cleared
        bfOptions.inInputShareable=true;              //Which kind of reference will be used to recover the Bitmap data after being clear, when it will be used in the future
        bfOptions.inTempStorage=new byte[32 * 1024];
        if (convertView == null) {
            imageView = new ImageView(context);
            imageView.setLayoutParams(new GridView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
            imageView.setPadding(0, 0, 0, 0);
        } else {
            imageView = (ImageView) convertView;
        }
        FileInputStream fs = null;
        Bitmap bm;
        try {
            fs = new FileInputStream(new File(imgPic.get(position).toString()));
            if(fs!=null) {
                bm=BitmapFactory.decodeFileDescriptor(fs.getFD(), null, bfOptions);
                imageView.setImageBitmap(bm);
                imageView.setId(position);
                imageView.setLayoutParams(new GridView.LayoutParams(500, 400));
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally{
            if(fs!=null) {
                try {
                    fs.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return imageView;
    }
}
}

布局代码是

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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=".CaptureActivity">

<RelativeLayout
    android:id="@+id/RelativeGridLayout"
    android:layout_width="wrap_content"
    android:layout_height="fill_parent">

    <GridView
        android:id="@+id/gridviewimg"
        android:layout_width="match_parent"
        android:layout_height="620dp"
        android:gravity="center"
        android:numColumns="2"
        android:paddingTop="10dp"
        android:paddingBottom="10dp"
        android:scrollbarStyle="outsideInset"
        android:smoothScrollbar="true"
        android:verticalSpacing="10dp"></GridView>

</RelativeLayout>

<RelativeLayout
    android:id="@+id/RelativeLayout01"
    android:layout_width="match_parent"
    android:layout_height="57dp"
    android:layout_alignBottom="@+id/RelativeGridLayout"
    android:layout_marginBottom="0dp">

    <ImageButton
        android:id="@+id/imageButtonCam"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_marginTop="5dp"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"

        android:onClick="captureImage"
        app:srcCompat="@drawable/camerabutton" />

    <Button
        android:id="@+id/buttonNexta"
        android:layout_width="82dp"
        android:layout_height="40dp"
        android:layout_marginTop="10dp"
        android:layout_alignParentTop="true"
        android:layout_alignParentRight="true"

        android:background="@drawable/btn"
        android:text="Exit"
        android:textSize="19dp" />


</RelativeLayout>

标签： javascriptjavaandroidperformanceandroid-studio