Android实现相册中图片上传或下载

这篇文章主要为大家详细介绍了Android实现相册中图片上传或下载，具有一定的参考价值，感兴趣的小伙伴们可以参考一下

本文实例为大家分享了Android实现相册中图片上传或下载的具体代码，供大家参考，具体内容如下

目标效果：

打开相册选择一张图片，会显示到上方的ImageView中并存储到Bmob中，存储后进入Bmob后台，复制刚才添加的数据的objectId，粘贴到代码指定出，然后运行，点击下载会在下方的ImageView显示刚才上传的图片，这里的下载是指定objectId，可以进行动态获取objectId进行下载。

1.activity_main.xml页面设置布局。

activity_main.xml页面：

2.MainActivity.java页面定义上传与下载方法。

MainActivity.java页面：

 package com.example.text; import java.io.File; import cn.bmob.v3.Bmob; import cn.bmob.v3.BmobQuery; import cn.bmob.v3.datatype.BmobFile; import cn.bmob.v3.listener.DownloadFileListener; import cn.bmob.v3.listener.GetListener; import cn.bmob.v3.listener.UploadBatchListener; import cn.bmob.v3.listener.UploadFileListener; import com.android.volley.toolbox.ImageLoader; import com.example.text.MainActivity; import entity.Person; import android.net.Uri; import android.os.Bundle; import android.os.Environment; import android.provider.MediaStore; import android.app.Activity; import android.content.Intent; import android.database.Cursor; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.drawable.BitmapDrawable; import android.graphics.drawable.Drawable; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.ImageView; import android.widget.Toast; public class MainActivity extends Activity implements OnClickListener { private ImageView ivHead, ivDownload; private Button btnSelectImage, btnDownloadImage; private static final int IMAGE_CODE = 0;// 打开相册 private static final int RESIZE_CODE = 2;// 调整大小 private static final String IMAGE_NAME = " ";// 图片字符串 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Bmob.initialize(this, "8ef8a4752f48682eadb32d3c8c8e398f");// 初始化Bmob // 初始化控件 init(); // 绑定点击事件 bindClick(); } // 初始化控件 private void init() { ivHead = (ImageView) findViewById(R.id.ivHead); ivDownload = (ImageView) findViewById(R.id.ivDownload); btnSelectImage = (Button) findViewById(R.id.btnSelectImage); btnDownloadImage = (Button) findViewById(R.id.btnDownloadImage); } // 绑定点击事件 private void bindClick() { btnSelectImage.setOnClickListener(this); btnDownloadImage.setOnClickListener(this); } @Override public void onClick(View view) { switch (view.getId()) { case R.id.btnSelectImage: Intent galleryIntent = new Intent(Intent.ACTION_GET_CONTENT); galleryIntent.addCategory(Intent.CATEGORY_OPENABLE); galleryIntent.setType("image/*");//图片 startActivityForResult(galleryIntent, IMAGE_CODE);  //跳转，传递打开相册请求码 break; case R.id.btnDownloadImage: BmobQuery query=new BmobQuery(); query.getObject(this,"ef292ff6ef",new GetListener() { //第二个参数为想要下载的BmobFile数据的objectId @Override public void onSuccess(Person person) { Toast.makeText(MainActivity.this,"获取成功",Toast.LENGTH_SHORT).show(); //下载图片 downloadImage(person); } @Override public void onFailure(int arg0, String arg1) { Toast.makeText(MainActivity.this,"获取失败",Toast.LENGTH_SHORT).show(); } }); break; default: break; } } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (resultCode != RESULT_OK) { return; } else { switch (requestCode) { case IMAGE_CODE: Uri uri = data.getData(); resizeImage(uri); // 将获取到的uri转换为String型 String[] images = { MediaStore.Images.Media.DATA };// 将图片URI转换成存储路径 Cursor cursor = this .managedQuery(uri, images, null, null, null); int index = cursor .getColumnIndexOrThrow(MediaStore.Images.Media.DATA); cursor.moveToFirst(); String img_url = cursor.getString(index); upload(img_url); break; case RESIZE_CODE: if (data != null) { showResizeImage(data); } break; } } super.onActivityResult(requestCode, resultCode, data); } // 判断SD卡是否存在 private boolean isSdcardExisting() { final String state = Environment.getExternalStorageState(); if (state.equals(Environment.MEDIA_MOUNTED)) { return true; } else { return false; } } // 重塑图片大小 public void resizeImage(Uri uri) { Intent intent = new Intent("com.android.camera.action.CROP"); intent.setDataAndType(uri, "image/*"); intent.putExtra("crop", "true");// 可以裁剪 intent.putExtra("aspectX", 1); intent.putExtra("aspectY", 1); intent.putExtra("outputX", 150); intent.putExtra("outputY", 150); intent.putExtra("return-data", true); startActivityForResult(intent, RESIZE_CODE);// 跳转，传递调整大小请求码 } // 获取路径 private Uri getImageUri() { return Uri.fromFile(new File(Environment.getExternalStorageDirectory(), IMAGE_NAME)); } // 显示图片 private void showResizeImage(Intent data) { Bundle extras = data.getExtras(); if (extras != null) { Bitmap photo = extras.getParcelable("data"); Drawable drawable = new BitmapDrawable(photo); ivHead.setImageDrawable(drawable); } } // 图片上传 private void upload(String imgpath) { final BmobFile icon = new BmobFile(new File(imgpath)); icon.upload(this, new UploadFileListener() { @Override public void onSuccess() { Person person = new Person(); person.setIcon(icon); person.save(MainActivity.this); Toast.makeText(MainActivity.this,"图片上传成功",Toast.LENGTH_SHORT).show(); } @Override public void onFailure(int arg0, String arg1) { Toast.makeText(MainActivity.this,"图片上传失败",Toast.LENGTH_SHORT).show(); } }); } //下载图片 private void downloadImage(Person person) { BmobFile icon=person.getIcon(); icon.download(MainActivity.this,new DownloadFileListener() { @Override public void onSuccess(String url) { ivDownload.setImageBitmap(BitmapFactory.decodeFile(url));  //根据地址解码并显示图片 } @Override public void onFailure(int arg0, String arg1) { Toast.makeText(MainActivity.this,"下载失败",Toast.LENGTH_SHORT).show(); } }); } }

3.Person.java页面为实体类，运行自动生成一个Person表，这个表只有一个字段存储图片。

Person.java页面：

 package entity; import cn.bmob.v3.BmobObject; import cn.bmob.v3.datatype.BmobFile; public class Person extends BmobObject{ private BmobFile icon; public BmobFile getIcon() { return icon; } public void setIcon(BmobFile icon) { this.icon = icon; } }

4.因为使用了Bmob，所以需要添加权限。

AndroidManifest.xml页面：

5.注意之前讲过使用Bmob需要下载第三方SDK，将libs文件夹中的所有内容都复制到项目libs目录下，然后Properties->Java Build Path->Libraries->Add JARs...添加刚复制的四个jar包