Uri转化为filepath的方法，及压缩图片的方法

源码地址：https://github.com/heinika/MyCream

1,4.4之前Uri转化为filepath的方法

public class GetPathFromUriBeforekitkat {
private static String filename;
private static Cursor cursor;
public static String getPath(final Context context, final Uri data) {
if (data.getScheme().toString().compareTo("content") == 0) {
cursor =context.getContentResolver().query(data,
new String[] {MediaStore.Audio.Media.DATA}, null, null, null);
if (cursor.moveToFirst()) {
filename = cursor.getString(0);
}
        }else if (data.getScheme().toString().compareTo("file") == 0)         //file:///开头的uri
{
filename = data.toString();
filename = data.toString().replace("file://", "");
//替换file://
if(!filename.startsWith("/mnt")){
//加上"/mnt"头
filename += "/mnt";
}
        }
return filename;
}
}

2,4.4及之后Uri转化为filepath的方法

package com.apple.mycream.utils;

import android.annotation.SuppressLint;
import android.content.ContentUris;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.DocumentsContract;
import android.provider.MediaStore;

/**
 * Created by Administrator on 2015/9/16.
 */
public class GetPathFromUri4kikat {
/**
     * 专为Android4.4设计的从Uri获取文件绝对路径，以前的方法已不好使
*/
@SuppressLint("NewApi")
public static String getPath(final Context context, final Uri uri) {

final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;

// DocumentProvider
if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
// ExternalStorageProvider
if (isExternalStorageDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];

if ("primary".equalsIgnoreCase(type)) {
return Environment.getExternalStorageDirectory() + "/" + split[1];
}

// TODO handle non-primary volumes
}
// DownloadsProvider
else if (isDownloadsDocument(uri)) {

final String id = DocumentsContract.getDocumentId(uri);
final Uri contentUri = ContentUris.withAppendedId(
                        Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));

return getDataColumn(context, contentUri, null, null);
}
// MediaProvider
else if (isMediaDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];

Uri contentUri = null;
if ("image".equals(type)) {
                    contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
} else if ("video".equals(type)) {
                    contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
} else if ("audio".equals(type)) {
                    contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
}

final String selection = "_id=?";
final String[] selectionArgs = new String[] { split[1] };

return getDataColumn(context, contentUri, selection, selectionArgs);
}
        }
// MediaStore (and general)
else if ("content".equalsIgnoreCase(uri.getScheme())) {
return getDataColumn(context, uri, null, null);
}
// File
else if ("file".equalsIgnoreCase(uri.getScheme())) {
return uri.getPath();
}

return null;
}

/**
     * Get the value of the data column for this Uri. This is useful for
     * MediaStore Uris, and other file-based ContentProviders.
     *
     * @param context
*            The context.
     * @param uri
*            The Uri to query.
     * @param selection
*            (Optional) Filter used in the query.
     * @param selectionArgs
*            (Optional) Selection arguments used in the query.
     * @return The value of the _data column, which is typically a file path.
     */
public static String getDataColumn(Context context, Uri uri, String selection,
                                       String[] selectionArgs) {

        Cursor cursor = null;
final String column = "_data";
final String[] projection = { column };

try {
            cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
null);
if (cursor != null && cursor.moveToFirst()) {
final int column_index = cursor.getColumnIndexOrThrow(column);
return cursor.getString(column_index);
}
        } finally {
if (cursor != null)
                cursor.close();
}
return null;
}

/**
     * @param uri
*            The Uri to check.
     * @return Whether the Uri authority is ExternalStorageProvider.
     */
public static boolean isExternalStorageDocument(Uri uri) {
return "com.android.externalstorage.documents".equals(uri.getAuthority());
}

/**
     * @param uri
*            The Uri to check.
     * @return Whether the Uri authority is DownloadsProvider.
     */
public static boolean isDownloadsDocument(Uri uri) {
return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}

/**
     * @param uri
*            The Uri to check.
     * @return Whether the Uri authority is MediaProvider.
     */
public static boolean isMediaDocument(Uri uri) {
return "com.android.providers.media.documents".equals(uri.getAuthority());
}
}

3，压缩图片的方法

/**
 * Created by Administrator on 2015/9/16.
 */
public class ZipMethod {
/**
     * 压缩图片的方法
* @param savePath
*/
public static  void zipImage(String savePath) {
        Log.d("kaka", "zip");
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(savePath, options);
options.inSampleSize = computeInitialSampleSize(options, 480, 480 * 960);
options.inJustDecodeBounds = false;
Bitmap bitmap = BitmapFactory.decodeFile(savePath, options);
try {
            FileOutputStream fos = new FileOutputStream(savePath);
bitmap.compress(Bitmap.CompressFormat.JPEG, 90, fos);
fos.flush();
fos.close();
} catch (IOException e) {
            e.printStackTrace();
}
        bitmap.recycle();
bitmap = null;
System.gc();
}
public static int computeSampleSize(BitmapFactory.Options options,
int minSideLength, int maxNumOfPixels) {
int initialSize = computeInitialSampleSize(options, minSideLength,
                maxNumOfPixels);
int roundedSize;
if (initialSize <= 8) {
            roundedSize = 1;
while (roundedSize < initialSize) {
                roundedSize <<= 1;
}
        } else {
            roundedSize = (initialSize + 7) / 8 * 8;
}
return roundedSize;
}

private static int computeInitialSampleSize(BitmapFactory.Options options,
int minSideLength, int maxNumOfPixels) {
double w = options.outWidth;
double h = options.outHeight;
int lowerBound = (maxNumOfPixels == -1) ? 1 : (int) Math.ceil(Math
                .sqrt(w * h / maxNumOfPixels));
int upperBound = (minSideLength == -1) ? 128 : (int) Math.min(
                Math.floor(w / minSideLength), Math.floor(h / minSideLength));
if (upperBound < lowerBound) {
// return the larger one when there is no overlapping zone.
return lowerBound;
}
if ((maxNumOfPixels == -1) && (minSideLength == -1)) {
return 1;
} else if (minSideLength == -1) {
return lowerBound;
} else {
return upperBound;
}
    }

}