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