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2021-11-23 10:52
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gridview中点击图片后无法跳转

在实现了gridview显示文件内图片的功能之后,想要添加点击图片跳转页面显示图片的效果。
但是只能完成跳转不能完成显示
这是文件图片预览界面

img


点击后跳转页面

img

album.java 
package com.example.mycamera2021a;

import android.app.Activity;
import android.app.ActivityOptions;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.util.ArrayList;
import java.util.List;

public class album extends AppCompatActivity {
    /**
     * 显示图片的GridView
     */
    private GridView gvPhoto;
    /**
     * 文件夹下所有图片的bitmap
     */
    private List<Bitmap> listpath;
    /**
     * 文件夹下图片的真实路径
     */
    private String scanpath;
    /**
     * 显示图片的适配器
     */
    private Photodaapter adapter;
    /**
     * 所有图片的名字
     */
    public String[] allFiles;
    /**
     * 想要查找的文件夹
     */
    private File folder;
    /**
     * 返回主界面
     */
    private Button btn1;

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.album);
        btn1 = (Button) findViewById(R.id.return1);

        btn1.setOnClickListener(new View.OnClickListener() {
            /**
             * 跳转功能
             * @param
             */
            @Override
            public void onClick(View v) {
                Intent i = new Intent(album.this, MainActivity.class);
                startActivity(i);
            }
        });
        /**将gvphoho部署在GridView中*/
        gvPhoto = (GridView) findViewById(R.id.view1);
        initData();
        /**给GridView中添加点击控件*/
        gvPhoto.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Intent intent = new Intent(album.this, photo.class);
                intent.putExtra("path",allFiles[position]);
                startActivity(intent);
            }
        });

    }

    private void initData() {
        listpath = new ArrayList<>();
        folder = new File(Environment.getExternalStorageDirectory().toString(),"/mycamera");
        /**将文件夹下所有文件名存入数组*/
        allFiles = folder.list();
        /**遍历数组*/
        for (int i = 0; i < allFiles.length; i++) {
          scanpath = folder + "/" + allFiles[i];
            /**将文件转为bitmap如果为空则不是图片文件*/
           Bitmap bitmap = BitmapFactory.decodeFile(scanpath);
           if (bitmap != null) {
             listpath.add(bitmap);
           }
        }
        /** 图片写入适配器*/
        adapter = new Photodaapter(listpath, this);
        gvPhoto.setAdapter(adapter);

    }

    /**
     * item适配器
     */
    public class Photodaapter extends BaseAdapter {
        private List<Bitmap> mlist;
        private Context mcontext;
        private LayoutInflater minflater;
        private int selected = -1;

        public Photodaapter(List<Bitmap> list, Context context) {
            super();
            this.mlist = list;
            this.mcontext = context;
            this.minflater = LayoutInflater.from(context);
        }

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

        @Override
        public Object getItem(int position) {
            return mlist.get(position);
        }

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

        @Override
        public View getView(final int position, View convertView, final ViewGroup parent) {
            VIewHolder vh;

            if (convertView == null) {
                vh = new VIewHolder();
                convertView = minflater.inflate(R.layout.item, null);
                vh.iv = (ImageView) convertView.findViewById(R.id.iv_grid);
                convertView.setTag(vh);
            } else {
                vh = (VIewHolder) convertView.getTag();
            }
            vh.iv.setImageBitmap(mlist.get(position));
            Bitmap path = mlist.get(position);
            return convertView;
        }
    }

    class VIewHolder {
        ImageView iv;
    }

}


photo.java
package com.example.mycamera2021a;

import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

import java.io.ByteArrayOutputStream;

public class photo extends AppCompatActivity {

    private ImageView imageView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.photo);
        imageView  = (ImageView)findViewById(R.id.imageView_cen);
        Intent it = getIntent();
        final int imageRId = it.getExtras().getInt("path");
        imageView.setImageResource(imageRId);
        }
    }

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