从数组列表中获取文件名

Question

我将如何从这个 PageAdapter 中获取文件名，以便可以将其用作字符串来删除图像。

我尝试将 viewPager.setCurrentItem(position) 转换为字符串，我尝试将 viewPager.getCurrentItem() 转换，我尝试将 Bitmap 转换为字符串...我没有想法，现在请教各位专家。

我已经在 stackoverflow 和 Google 上搜索了 3 天，但找不到任何可以帮助我的东西。

您能提供的任何帮助将不胜感激。

FullScreenViewActivity.java

package com.company.imageslider;

import com.company.imageslider.adapter.FullScreenImageAdapter;
import com.company.imageslider.helper.Utils;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.view.ViewPager;

public class FullScreenViewActivity extends Activity{

    private Utils utils;
    private FullScreenImageAdapter adapter;
    private ViewPager viewPager;

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

        viewPager = (ViewPager) findViewById(R.id.pager);

        utils = new Utils(getApplicationContext());

        Intent i = getIntent();
        int position = i.getIntExtra("position", 0);

        adapter = new FullScreenImageAdapter(FullScreenViewActivity.this,
                utils.getFilePaths());

        viewPager.setAdapter(adapter);

        // displaying selected image first
        viewPager.setCurrentItem(position);
    }
}

FullScreenImageAdapter.java

package com.company.imageslider.adapter;

import com.company.imageslider.R;
import com.company.imageslider.helper.TouchImageView;

import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.RelativeLayout;

public class FullScreenImageAdapter extends PagerAdapter {

    private Activity _activity;
    private ArrayList<String> _imagePaths;
    private LayoutInflater inflater;

    // constructor
    public FullScreenImageAdapter(Activity activity,
            ArrayList<String> imagePaths) {
        this._activity = activity;
        this._imagePaths = imagePaths;
    }

    @Override
    public int getCount() {
        return this._imagePaths.size();
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == ((RelativeLayout) object);
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        TouchImageView imgDisplay;
        Button btnClose;

        inflater = (LayoutInflater) _activity
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View viewLayout = inflater.inflate(R.layout.layout_fullscreen_image, container,
                false);

        imgDisplay = (TouchImageView) viewLayout.findViewById(R.id.imgDisplay);
        btnClose = (Button) viewLayout.findViewById(R.id.btnClose);

        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inPreferredConfig = Bitmap.Config.ARGB_8888;
        Bitmap bitmap = BitmapFactory.decodeFile(_imagePaths.get(position), options);
        imgDisplay.setImageBitmap(bitmap);

        // close button click event
        btnClose.setOnClickListener(new View.OnClickListener() {            
            @Override
            public void onClick(View v) {
                _activity.finish();
            }
        }); 

        ((ViewPager) container).addView(viewLayout);

        return viewLayout;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        ((ViewPager) container).removeView((RelativeLayout) object);

    }

}

Utils.java

package com.company.imageslider.helper;

import java.io.File;
import java.util.ArrayList;
import java.util.Locale;

import android.app.AlertDialog;
import android.content.Context;
import android.graphics.Point;
import android.view.Display;
import android.view.WindowManager;
import android.widget.Toast;

public class Utils {

    private Context _context;

    // constructor
    public Utils(Context context) {
        this._context = context;
    }

    /*
     * Reading file paths from SDCard
     */
    public ArrayList<String> getFilePaths() {
        ArrayList<String> filePaths = new ArrayList<String>();

        File directory = new File(
                android.os.Environment.getExternalStorageDirectory()
                        + File.separator + AppConstant.PHOTO_ALBUM);

        // check for directory
        if (directory.isDirectory()) {
            // getting list of file paths
            File[] listFiles = directory.listFiles();

            // Check for count
            if (listFiles.length > 0) {

                // loop through all files
                for (int i = 0; i < listFiles.length; i++) {

                    // get file path
                    String filePath = listFiles[i].getAbsolutePath();

                    // check for supported file extension
                    if (IsSupportedFile(filePath)) {
                        // Add image path to array list
                        filePaths.add(filePath);
                    }
                }
            } else {
                // image directory is empty
                Toast.makeText(
                        _context,
                        AppConstant.PHOTO_ALBUM
                                + " is empty. Please load some images in it !",
                        Toast.LENGTH_LONG).show();
            }

        } else {
            AlertDialog.Builder alert = new AlertDialog.Builder(_context);
            alert.setTitle("Error!");
            alert.setMessage(AppConstant.PHOTO_ALBUM
                    + " directory path is not valid! Please set the image directory name AppConstant.java class");
            alert.setPositiveButton("OK", null);
            alert.show();
        }

        return filePaths;
    }

    /*
     * Check supported file extensions
     * 
     * @returns boolean
     */
    private boolean IsSupportedFile(String filePath) {
        String ext = filePath.substring((filePath.lastIndexOf(".") + 1),
                filePath.length());

        if (AppConstant.FILE_EXTN
                .contains(ext.toLowerCase(Locale.getDefault())))
            return true;
        else
            return false;

    }

    /*
     * getting screen width
     */
    public int getScreenWidth() {
        int columnWidth;
        WindowManager wm = (WindowManager) _context
                .getSystemService(Context.WINDOW_SERVICE);
        Display display = wm.getDefaultDisplay();

        final Point point = new Point();
        try {
            display.getSize(point);
        } catch (java.lang.NoSuchMethodError ignore) { // Older device
            point.x = display.getWidth();
            point.y = display.getHeight();
        }
        columnWidth = point.x;
        return columnWidth;
    }
}

AppConstant.java

package com.company.imageslider.helper;

import java.util.Arrays;
import java.util.List;

public class AppConstant {

    // Number of columns of Grid View
    public static final int NUM_OF_COLUMNS = 3;

    // Gridview image padding
    public static final int GRID_PADDING = 8; // in dp

    // SD card image directory
    public static final String PHOTO_ALBUM = "NAT";

    // supported file formats
    public static final List<String> FILE_EXTN = Arrays.asList("jpg", "jpeg",
            "png");
}

Answer 1

您没有从适配器获取图像路径。你从你的数组列表中得到它：_imagePaths

使用

 String path = _imagePaths.get(mViewPager.getCurrentItem());