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我想用android做一些繪圖。我有一臺audioplayer，它從服務器獲取波形圖。我想畫出這張照片。 （不要鏈接我的可視化例子，這不是我所期待的）。我發現這個教程（http://www.droidnova.com/playing-with-graphics-in-android-part-i,147.html），和我做了這個 我查看的子類：android ImageView子類不能正常顯示
public class WaveFormSurfaceView extends View {
Bitmap waveform = null;
public WaveFormSurfaceView(Context context) {
super(context);
}
public WaveFormSurfaceView(Context context, AttributeSet attrs){
super(context,attrs);
}
public WaveFormSurfaceView(Context context, AttributeSet attrs, int defStyle){
super(context,attrs,defStyle);
}
//copies the given waveform to a variable
public void setWaveForm(Bitmap b) {
waveform = Bitmap.createBitmap(b.getWidth(),
b.getHeight(), b.getConfig());
// copy the pixel to it
int[] allpixels = new int[b.getHeight() * b.getWidth()];
b.getPixels(allpixels, 0, b.getWidth(), 0, 0,
b.getWidth(), b.getHeight());
waveform.setPixels(allpixels, 0, b.getWidth(), 0, 0,
b.getWidth(), b.getHeight());
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
//super.onDraw(canvas);
// Create a paint object for us to draw with, and set our drawing color
// to blue.
Paint paint = new Paint();
paint.setColor(Color.RED);
paint.setAlpha(50);
// draws the rectangle
if(waveform!=null){
canvas.drawRect(0, 0, (float)0.5 * waveform.getWidth(),
waveform.getHeight(), paint);
}else{
canvas.drawRect(0, 0,50,
50, paint);
}
//mImageView.setImageBitmap(map);
}
}
這裏是我的活動：
public class AudioPlayerActivity extends Activity{
// Hardcoded parameters for the Verba demo server
private static final String ServerURL = "http://something.com";
private static final String MediaPath = "C:\\path\\media\\";
// Player user interface elements
private Button mBtnPlay;
private WaveFormSurfaceView mImageView;
//private ImageView mImageView;
private SeekBar mSeekBar;
private TextView mCurrentPos;
private TextView mEndPos;
private Bitmap originalWaveForm;
// THIS IS THE MEDIAPLAYER (has no UI, only loads and plays the audio)
private MediaPlayer mMediaPlayer;
// HTTP URL for the audio waveform PNG picture
private String getWaveformURL(String pCallURL) {
return ServerURL + ":8089/a?" + MediaPath + pCallURL
+ "?1000020024024024";
}
// HTTP URL for the audio transcoded to MP3 format
private String getMediaURL(String pCallURL) {
return ServerURL + ":10100/getMedia?file=" + MediaPath + pCallURL
+ "&format=mp3";
}
// Downloads the waveform image outside of the main GU thread
private class DownloadWaveformTask extends AsyncTask<String, Void, Bitmap> {
@Override
protected Bitmap doInBackground(String... urls) {
try {
return BitmapFactory.decodeStream((InputStream) new URL(
getWaveformURL(myCallURL))
.getContent());
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Bitmap result) {
//mImageView.setImageBitmap(result);
//setWaveForm(result);
mImageView.setWaveForm(result);
}
}
// Updates the seekbar outside of the main GU thread, started only after
// MediaPlayer exists
private class SeekBarUpdater extends Thread {
float p=0;
@Override
public void run() {
final SimpleDateFormat tf = new SimpleDateFormat("mm:ss.SSS");
final Calendar calendar = Calendar.getInstance();
int currentPosition = 0;
final int total = mMediaPlayer.getDuration(); // //returns in msec,
// final because we
// will use in the
// runnable
// UI update must happen on the UI thread, so we post our actions
// there in a runnable
mCurrentPos.post(new Runnable() {
public void run() {
calendar.setTimeInMillis(total);
mEndPos.setText(tf.format(calendar.getTime()));
mSeekBar.setMax(total);
}
});
while (mMediaPlayer != null && currentPosition < total) {
try {
Thread.sleep(50);
currentPosition = mMediaPlayer.getCurrentPosition(); // returns
// in
// msec
} catch (InterruptedException e) {
return;
} catch (Exception e) {
return;
}
// we are roughly adjusting for delays due to the thread
// communication
// currentPosition -= 100;
// if (currentPosition < 0) currentPosition = 0;
final int currPosition = currentPosition; // final because we
// will use in the
// runnable
p=(float)currentPosition/(float)total;
// UI update must happen on the UI thread, so we post our
// actions there in a runnable
mCurrentPos.post(new Runnable() {
public void run() {
calendar.setTimeInMillis(currPosition);
mCurrentPos.setText(tf.format(calendar.getTime()));
mSeekBar.setProgress(currPosition);
System.out.println("pecent="+p);
drawRectOnWaveForm(p);
}
});
}
}
}
String myCallURL;
/**
* Create a new instance of MyFragment that will be initialized
* with the given arguments.
*/
static MediaPlayerFragment newInstance(CharSequence url) {
MediaPlayerFragment f = new MediaPlayerFragment();
Bundle args = new Bundle();
args.putCharSequence("call_url", url);
f.setArguments(args);
return f;
}
/**
* During creation, if arguments have been supplied to the fragment
* then parse those out.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bundle extras = getIntent().getExtras();
if (extras != null) {
String value1 = extras.getString("call_url");
if(value1!=null){
myCallURL=value1;
}
}
setContentView(R.layout.mediaplayer);
System.out.println("AudioPlayerActivity setContentView, mycallurl: "+myCallURL);
DownloadWaveformTask task = new DownloadWaveformTask();
task.execute();
// part of the player UI
//mImageView = (ImageView) findViewById(R.id.imageView);
mImageView = (WaveFormSurfaceView) findViewById(R.id.imageView);
mBtnPlay = (Button) findViewById(R.id.playButton);
mSeekBar = (SeekBar) findViewById(R.id.seekBar);
mCurrentPos = (TextView) findViewById(R.id.currentPos);
mEndPos = (TextView) findViewById(R.id.endPos);
Button drawButton=(Button) findViewById(R.id.button1);
//
mSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
if (fromUser) {
// we only update the player if the change comes from a user
// action
mMediaPlayer.seekTo(progress);
}
}
});
// IMPORTANT
// - The DownloadWaveformTask part should go into the initialization of
// the player fragment
// - currently we are NOT handling currently the end of playback
// situations, we should
// - currently we are NOT releasing the MediaPlayer resource, we should
// when a fragment closes
mBtnPlay.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (mMediaPlayer != null) {
if (mMediaPlayer.isPlaying()) {
mMediaPlayer.pause();
mBtnPlay.setText("Play");
} else {
mMediaPlayer.start();
mBtnPlay.setText("Pause");
}
} else {
mMediaPlayer = new MediaPlayer();
mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
// this updates the seekbar as the buffering happens
mMediaPlayer
.setOnBufferingUpdateListener(new MediaPlayer.OnBufferingUpdateListener() {
@Override
public void onBufferingUpdate(MediaPlayer mp,
int percent) {
// TODO Auto-generated method stub
mSeekBar.setSecondaryProgress((int) (mSeekBar
.getMax() * percent/100));
}
});
try {
final String lMediaURL = getMediaURL(myCallURL);
mMediaPlayer.setDataSource(lMediaURL);
mMediaPlayer.prepare(); // might take long! (for
// buffering, etc)
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
mMediaPlayer.start();
mBtnPlay.setText("Pause");
// we start the thread that updates the seekbar, based on
// the state of the player
SeekBarUpdater thread = new SeekBarUpdater();
thread.start();
}
}
});
// Close button
Button closeBtn = (Button) findViewById(R.id.closebtn);
closeBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//TODO ha megy a lejátszás, megállítjuk
if(mMediaPlayer!=null){
if(mMediaPlayer.isPlaying()){
mMediaPlayer.stop();
}
}
finish();
}
});
//myCallURL = getArguments().getString("call_url");
//myCallURL = savedInstanceState.getString("call_url");
//int style = DialogFragment.STYLE_NORMAL;
//int theme = android.R.style.Theme_Dialog;
//setStyle(style, theme);
}
}
這裏是mediaplayer.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"
android:gravity="center"
>
<TableLayout
android:id="@+id/tableLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<TableRow
android:id="@+id/tableRow1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center" >
<adam.czibere.WaveFormSurfaceView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</TableRow>
<TableRow
android:id="@+id/tableRow2"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<SeekBar
android:id="@+id/seekBar"
android:layout_width="match_parent"
android:layout_weight="1"
android:layout_height="20dp"
android:layout_gravity="center"
android:thumb="@drawable/progress_fill" />
</TableRow>
<TableRow
android:id="@+id/tableRow3"
android:layout_width="wrap_content"
android:layout_height="fill_parent" >
<TextView
android:id="@+id/currentPos"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:gravity="right"
android:layout_weight="5"
android:text="00:00.000" />
<TextView
android:id="@+id/textView4"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:layout_weight="1"
android:text="/" />
<TextView
android:id="@+id/endPos"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="5"
android:gravity="left"
android:text="00:00.000" />
</TableRow>
<TableRow
android:id="@+id/tableRow4"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<Button
android:id="@+id/playButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Play" />
<Button
android:id="@+id/closebtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Close" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
android:layout_weight="1" />
</TableRow>
</TableLayout>
這是我得到的圖像http://i.stack.imgur.com/HULyi.png
我的問題是，所有其他小部件在哪裏？按鈕等？如果我正確地得到它，當我膨脹佈局時，波形圖像不是downloada呢？下載時如何畫出它？
我不知道你的應用程序的邏輯，我認爲你可以調用invalidate（）來重繪視圖。 – 2012-03-28 13:57:15