ANDROID笔记:通过ContentProvider得到SD卡的图片

 

activity:

package com.example.android_contentprovider;



import java.util.ArrayList;

import java.util.List;



import android.app.Activity;

import android.app.AlertDialog;

import android.content.Intent;

import android.database.Cursor;

import android.graphics.BitmapFactory;

import android.net.Uri;

import android.os.Bundle;

import android.os.Environment;

import android.provider.MediaStore;

import android.provider.MediaStore.Audio.Media;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemClickListener;

import android.widget.BaseAdapter;

import android.widget.GridView;

import android.widget.ImageView;

import android.widget.TextView;

import android.widget.Toast;



public class MainActivity extends Activity {

    // 图片数据集

    List<ImagePro> list = new ArrayList<ImagePro>();

    LayoutInflater inflater;



    @Override

    protected void onCreate(Bundle savedInstancetate) {

        super.onCreate(savedInstancetate);

        setContentView(R.layout.activity_main);

        inflater = LayoutInflater.from(MainActivity.this);

        // 重新扫描图片,添加新图片

        allScan();

        initData();

        GridView gridView = (GridView) findViewById(R.id.grid);

        gridView.setAdapter(adapter);

        gridView.setOnItemClickListener(new OnItemClickListener() {

            @Override

            public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,

                    long arg3) {

                View view = getLayoutInflater().inflate(R.layout.grid_item,

                        null);



                ImageView imageView = (ImageView) view

                        .findViewById(R.id.imageView1);

                TextView textView = (TextView) view.findViewById(R.id.text);



                imageView.setImageBitmap(BitmapFactory.decodeFile(list

                        .get(arg2).getData()));

                textView.setText(list.get(arg2).getName());

                // 弹出对话框

                new AlertDialog.Builder(MainActivity.this).setView(view)

                        .setPositiveButton("ok", null).show();

            }

        });

    }



    private void initData() {

        // 判断SD卡是否存在

        if (Environment.getExternalStorageState().equals(

                Environment.MEDIA_MOUNTED)) {

            // 获得存储卡的路径

            String sdpath = Environment.getExternalStorageDirectory() + "/";

            Toast.makeText(MainActivity.this, sdpath, Toast.LENGTH_LONG).show();

        } else {

            Toast.makeText(MainActivity.this, "null=========",

                    Toast.LENGTH_LONG).show();

        }

        // 使用MediaStore.Images.Media.EXTERNAL_CONTENT_URI,疯狂android讲义463页的Media.EXTERNAL_CONTENT_URI查找不到图片

        Cursor cursor = getContentResolver().query(

                MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null,

                null);

        while (cursor.moveToNext()) {

            ImagePro imagePro = new ImagePro();

            // 得到图片名称

            imagePro.setName(cursor.getString(cursor

                    .getColumnIndex(Media.DISPLAY_NAME)));

            // 得到图片尺寸

            imagePro.setDesc(cursor.getString(cursor.getColumnIndex(Media.SIZE)));

            // 得到图片路径

            byte[] path = cursor.getBlob(cursor.getColumnIndex(Media.DATA));

            imagePro.setData(new String(path, 0, path.length - 1));

            list.add(imagePro);

        }

    }



    /**

     * 扫描SD卡,添加新图片

     */

    public void allScan() {

        sendBroadcast(new Intent(

                Intent.ACTION_MEDIA_MOUNTED,

                Uri.parse("file://" + Environment.getExternalStorageDirectory())));

    }



    private BaseAdapter adapter = new BaseAdapter() {



        @Override

        public View getView(int arg0, View arg1, ViewGroup arg2) {

            // 不能直接显示全部图片,会内存溢出(OOM)

            View view = inflater.inflate(R.layout.grid_item, null);

            TextView textView = (TextView) view.findViewById(R.id.text);

            textView.setText(list.get(arg0).getName());

            return view;

        }



        @Override

        public long getItemId(int arg0) {

            // TODO Auto-generated method stub

            return arg0;

        }



        @Override

        public Object getItem(int arg0) {

            // TODO Auto-generated method stub

            return list.get(arg0);

        }



        @Override

        public int getCount() {

            // TODO Auto-generated method stub

            return list.size();

        }

    };



}

 

pojo类

package com.example.android_contentprovider;



public class ImagePro {

    private String name;

    private String desc;

    private String data;



    public String getName() {

        return name;

    }



    public void setName(String name) {

        this.name = name;

    }



    public String getDesc() {

        return desc;

    }



    public void setDesc(String desc) {

        this.desc = desc;

    }



    public String getData() {

        return data;

    }



    public void setData(String data) {

        this.data = data;

    }



    public ImagePro() {

    }



    public ImagePro(String name, String desc, String data) {

        super();

        this.name = name;

        this.desc = desc;

        this.data = data;

    }



}

 

 

activity_main.xml

 

<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"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".MainActivity" >



    <GridView

        android:id="@+id/grid"

        android:numColumns="2"

        android:layout_width="fill_parent"

        android:layout_height="fill_parent" >

    </GridView>



</RelativeLayout>

 

 

grid_item.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >



    <ImageView

        android:id="@+id/imageView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:src="@drawable/ic_launcher" />



    <TextView

        android:id="@+id/text"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content" 

        android:text="0000"/>



</LinearLayout>

 

 

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.example.android_contentprovider"

    android:versionCode="1"

    android:versionName="1.0" >



    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />

    <uses-permission android:name="android.permission.RESTART_PACKAGES" />



    <uses-sdk

        android:minSdkVersion="10"

        android:targetSdkVersion="17" />



    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name="com.example.android_contentprovider.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>

 

PS:权限需要写在activity前

 

android系统为其他的应用程序访问多媒体资源提供了ContentProvider

MediaStore.Audio.Media.EXTERNAL_CONTENT_URI:存储在SD卡上的音频文件ContentProvider的URI

MediaStore.Audio.Media.INTERNAL_CONTENT_URI:存储在手机内部存储器卡上的音频文件ContentProvider的URI

MediaStore.Images.Media.EXTERNAL_CONTENT_URI：存储在SD卡上的图像文件文件ContentProvider的URI

MediaStore.Images.Media.INTERNAL_CONTENT_URI:存储在手机内部存储器上图像文件ContentProvider的URI

MediaStore.Video.Media.INTERNAL_CONTENT_URI:存储在手机内部存储器上的视频文件ContentProvider的URI

MediaStore.Video.Media.EXTERNAL_CONTENT_URI：存储在SD卡上的视频文件ContentProvider的URI