<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="打開(kāi)相冊(cè)" />
 
 <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="下載圖片" />
 
 <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>

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;// 打開(kāi)相冊(cè)
 private static final int RESIZE_CODE = 2;// 調(diào)整大小
 
 private static final String IMAGE_NAME = " ";// 圖片字符串
 
 @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();
 
 // 綁定點(diǎn)擊事件
 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);
 }
 
 // 綁定點(diǎn)擊事件
 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/*");//圖片
  startActivityForResult(galleryIntent, IMAGE_CODE);  //跳轉(zhuǎn)，傳遞打開(kāi)相冊(cè)請(qǐng)求碼
  break;
 case R.id.btnDownloadImage:
  BmobQuery<Person> query=new BmobQuery<Person>();
  query.getObject(this,"ef292ff6ef",new GetListener<Person>() { //第二個(gè)參數(shù)為想要下載的BmobFile數(shù)據(jù)的objectId
  
  @Override
  public void onSuccess(Person person) {
   Toast.makeText(MainActivity.this,"獲取成功",Toast.LENGTH_SHORT).show();
   
   //下載圖片
   downloadImage(person);
  }
  
  @Override
  public void onFailure(int arg0, String arg1) {
   Toast.makeText(MainActivity.this,"獲取失敗",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);
  // 將獲取到的uri轉(zhuǎn)換為String型
  String[] images = { MediaStore.Images.Media.DATA };// 將圖片URI轉(zhuǎn)換成存儲(chǔ)路徑
  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);
 }
 
 // 判斷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;
 }
 }
 
 // 重塑圖片大小
 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);// 跳轉(zhuǎn)，傳遞調(diào)整大小請(qǐng)求碼
 }
 
 // 獲取路徑
 private Uri getImageUri() {
 return Uri.fromFile(new File(Environment.getExternalStorageDirectory(),
  IMAGE_NAME));
 }
 
 // 顯示圖片
 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);
 }
 }
 
 // 圖片上傳
 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,"圖片上傳成功",Toast.LENGTH_SHORT).show();
  }
 
  @Override
  public void onFailure(int arg0, String arg1) {
  Toast.makeText(MainActivity.this,"圖片上傳失敗",Toast.LENGTH_SHORT).show();
  }
 });
 }
 
 //下載圖片
 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));  //根據(jù)地址解碼并顯示圖片
  
  }
  
  @Override
  public void onFailure(int arg0, String arg1) {
  Toast.makeText(MainActivity.this,"下載失敗",Toast.LENGTH_SHORT).show();
  }
 });
 
 }
}

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;
 }
 
}

<?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"/>
  
  <!-- 允許聯(lián)網(wǎng) -->
  <uses-permission android:name="android.permission.INTERNET" />
  <!-- 獲取GSM（2g）、WCDMA（聯(lián)通3g）等網(wǎng)絡(luò)狀態(tài)的信息 -->
  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
  <!-- 獲取wifi網(wǎng)絡(luò)狀態(tài)的信息 -->
  <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
  <!-- 保持CPU 運(yùn)轉(zhuǎn)，屏幕和鍵盤燈有可能是關(guān)閉的,用于文件上傳和下載 -->
  <uses-permission android:name="android.permission.WAKE_LOCK" />
  <!-- 獲取sd卡寫的權(quán)限，用于文件上傳和下載 -->
  <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
  <!-- 允許讀取手機(jī)狀態(tài) 用于創(chuàng)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>