Android(安卓)学习笔记-2011年7月

7月25日：

下面是从网上看到的，能解析音频文件的专辑信息的，比如专辑图片。

public class Test extends Activity {    /** Called when the activity is first created. */    private ListView list;    private static final String sExternalMediaUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI.toString();    private static final Uri sArtworkUri = Uri.parse("content://media/external/audio/albumart");    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        Bitmap bm = null;        long songid = -1,albumid = -1;        Cursor cur = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null,null, null, null);        if(cur.moveToNext()){            songid = cur.getLong(0);            albumid = cur.getLong(12);        }        if (albumid < 0 && songid < 0) {            throw new IllegalArgumentException("Must specify an album or a song id");        }        try {            if (albumid < 0) {                Uri uri = Uri.parse("content://media/external/audio/media/" + songid + "/albumart");                ParcelFileDescriptor pfd = getContentResolver().openFileDescriptor(uri, "r");                if (pfd != null) {                    FileDescriptor fd = pfd.getFileDescriptor();                    bm = BitmapFactory.decodeFileDescriptor(fd);                }            } else {                Uri uri = ContentUris.withAppendedId(sArtworkUri, albumid);                ParcelFileDescriptor pfd = getContentResolver().openFileDescriptor(uri, "r");                if (pfd != null) {                    FileDescriptor fd = pfd.getFileDescriptor();                    bm = BitmapFactory.decodeFileDescriptor(fd);                }            }        } catch (FileNotFoundException ex) {            //        }        BitmapDrawable bmpDraw = new BitmapDrawable(bm);        ImageView image = (ImageView)findViewById(R.id.album);        image.setImageDrawable(bmpDraw);    }   }

获取图片：

private String getAlbumArt(int trackId) {//trackId是音乐的id        String mUriTrack = "content://media/external/audio/media/#";        String[] projection = new String[] {"album_id"};        String selection = "_id = ?";        String[] selectionArgs = new String[] {Integer.toString(trackId)};                Cursor cur = context.getContentResolver().query(Uri.parse(mUriTrack), projection, selection, selectionArgs, null);        int album_id = 0;        if (cur.getCount() > 0 && cur.getColumnCount() > 0) {            cur.moveToNext();            album_id = cur.getInt(0);        }        cur.close();        cur = null;        if (album_id < 0) {            return null;        }        String mUriAlbums = "content://media/external/audio/albums";        projection = new String[] {"album_art"};        cur = context.getContentResolver().query(Uri.parse(mUriAlbums + "/" + Integer.toString(album_id)), projection, null, null, null);        String album_art = null;        if (cur.getCount() > 0 && cur.getColumnCount() > 0) {            cur.moveToNext();            album_art = cur.getString(0);        }        cur.close();        cur = null;                    return album_art;    }

7月31日图片缩放

这是来自eoe的代码，我找来尝试解析时间：

是专门实现图片放大变小的代码，package com.jinyan.TestImage;import java.io.IOException;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Matrix;import android.graphics.drawable.BitmapDrawable;import android.graphics.drawable.Drawable;import android.os.Bundle;import android.util.Log;import android.widget.Button;import android.widget.ImageView;public class TestImage extends Activity {        /** Called when the activity is first created. */        private static final String tag = "TestImage.............";                String imageUrl = "http://i.pbase.com/o6/92/229792/1/80199697.uAs58yHk.50pxCross_of_the_Knights_Templar_svg.png";        Bitmap bmImg;        ImageView imView;        Button button1;        @Override        public void onCreate(Bundle savedInstanceState) {                super.onCreate(savedInstanceState);                setContentView(R.layout.main);                imView = (ImageView) findViewById(R.id.imview);                imView.setImageBitmap(returnBitMap(imageUrl));                Bitmap bitmap = returnBitMap(imageUrl);                imView.setImageDrawable(resizeImage(bitmap, 600, 600));        }                public Bitmap returnBitMap(String url) {                URL myFileUrl = null;                Bitmap bitmap = null;                try {                        myFileUrl = new URL(url);                } catch (MalformedURLException e) {                        e.printStackTrace();                }                try {                        HttpURLConnection conn = (HttpURLConnection) myFileUrl                                        .openConnection();                        conn.setDoInput(true);                        conn.connect();                        InputStream is = conn.getInputStream();                        bitmap = BitmapFactory.decodeStream(is);                        is.close();                } catch (IOException e) {                        e.printStackTrace();                }                Log.v(tag,bitmap.toString());                                return bitmap;        }        public static Drawable resizeImage(Bitmap bitmap, int w, int h) {                // load the origial Bitmap                Bitmap BitmapOrg = bitmap;                int width = BitmapOrg.getWidth();                int height = BitmapOrg.getHeight();                int newWidth = w;                int newHeight = h;                                Log.v(tag,String.valueOf(width));                Log.v(tag,String.valueOf(height));                                Log.v(tag,String.valueOf(newWidth));                Log.v(tag,String.valueOf(newHeight));                // calculate the scale                float scaleWidth = ((float) newWidth) / width;                float scaleHeight = ((float) newHeight) / height;                // create a matrix for the manipulation                Matrix matrix = new Matrix();                // resize the Bitmap                matrix.postScale(scaleWidth, scaleHeight);                // if you want to rotate the Bitmap                // matrix.postRotate(45);                // recreate the new Bitmap                Bitmap resizedBitmap = Bitmap.createBitmap(BitmapOrg, 0, 0, width,                                height, matrix, true);                // make a Drawable from Bitmap to allow to set the Bitmap                // to the ImageView, ImageButton or what ever                return new BitmapDrawable(resizedBitmap);        }        }

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