Android实现相册中图片上传或下载

2019-12-12 00:11:31

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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：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:tools="http://schemas.android.com/tools"  android:layout_width="match_parent"  android:layout_height="match_parent"  tools:context=".MainActivity" >  <ImageView    android:id="@+id/ivHead"   android:layout_marginTop="20dp"   android:layout_centerHorizontal="true"   android:layout_width="150dp"   android:layout_height="150dp"/>  <Button   android:id="@+id/btnSelectImage"   android:layout_width="match_parent"   android:layout_height="wrap_content"   android:layout_alignParentLeft="true"   android:layout_below="@+id/ivHead"   android:layout_marginTop="16dp"   android:text="打开相册" />  <Button   android:id="@+id/btnDownloadImage"   android:layout_width="match_parent"   android:layout_height="wrap_content"   android:layout_alignParentLeft="true"   android:layout_below="@+id/btnSelectImage"   android:text="下载图片" />  <ImageView   android:id="@+id/ivDownload"   android:layout_width="150dp"   android:layout_height="150dp"   android:layout_marginTop="20dp"   android:layout_centerHorizontal="true"   android:layout_below="@+id/btnDownloadImage" /> </RelativeLayout>

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<Person> query=new BmobQuery<Person>();  query.getObject(this,"ef292ff6ef",new GetListener<Person>() { //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：

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"  package="com.example.text"  android:versionCode="1"  android:versionName="1.0" >   <uses-sdk    android:minSdkVersion="8"    android:targetSdkVersion="18" />  <uses-permission android:name="android.permission.WRITE_CONTACTS"/>  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>  <uses-permission android:name="android.permission.INTERNET"/>    <!-- 允许联网 -->  <uses-permission android:name="android.permission.INTERNET" />  <!-- 获取GSM（2g）、WCDMA（联通3g）等网络状态的信息 -->  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />  <!-- 获取wifi网络状态的信息 -->  <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />  <!-- 保持CPU 运转，屏幕和键盘灯有可能是关闭的,用于文件上传和下载 -->  <uses-permission android:name="android.permission.WAKE_LOCK" />  <!-- 获取sd卡写的权限，用于文件上传和下载 -->  <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />  <!-- 允许读取手机状态 用于创建BmobInstallation -->  <uses-permission android:name="android.permission.READ_PHONE_STATE" />   <application    android:allowBackup="true"    android:icon="@drawable/ic_launcher"    android:label="@string/app_name"    android:theme="@style/AppTheme" >    <activity      android:name="com.example.text.MainActivity"      android:label="@string/app_name" >      <intent-filter>        <action android:name="android.intent.action.MAIN" />         <category android:name="android.intent.category.LAUNCHER" />      </intent-filter>    </activity>  </application> </manifest>

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