Android手机多媒体的应用

对《第一行代码——Android》的读书笔记

使用通知

通知是Android系统中比较特色的一个功能。发出一条通知后，手机最上方的状态栏会显示一个通知的图标，下拉状态栏后就可以看到通知的详细内容。

通知的基本用法

首先需要一个NotificationManger来对通知进行管理，可以调用Context的getSystemService（）方法获取到。getSystemService()方法接受一个字符串参数用于确定获取系统的那个服务，这里我们传入Context.NOTIFICATION_SERVICE即可。

NotificationManger manger=(NotificationManger)getSystemService(Context.NOTIFICATION_SERVICE);

接下来创建一个Nootification对象，这个对象用于存储通知所需的各种信息。

其构造函数接受三个参数：1.参数用于指定通知的图标

2.指定通知的ticker类型

3.指定通知被创建的时间

Notification notification =new Notification(R.drawable.icon,"this is ticker text",System.currentTimeMillis());

然后需要对通知的布局进行设定，这了只需调用Notification的setLatestEventInfo()方法就可以给通知设置一个标准的布局。

这个方法接受四个参数：

1.Context

2.制定标题内容

3.指定通知的内容

4.暂时传入NULL

Notification.setLatestEventInfo(context,"this is content title","this is content text",null);

都完成之后，只需调用NotificationManager的notify()方法就可以让通知显示出来。

该方法接受两个参数：

1.ID 保证每个通知所指定的Id都是不同的。

2.Notification对象

manager.notify(1,notification);

通知点击响应——PendingIntent

通过getActivity()，getBroadcast(),getService这几个静态方法都可以获得其对象。

这几个方法传入的参数都是相通的：

1.Context

2.通常传入0即可

3.Intent对象 通过这个对象创建出意图

4.用于确定PendingIntent的行为。

Notification.setLatestEventInfo()的第四个参数传入的就是PendingIntent.

public class MainActivity extends Activity implements OnClickListener {

private Button sendNotice;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sendNotice = (Button) findViewById(R.id.send_notice);
sendNotice.setOnClickListener(this);
}

@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.send_notice:
NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
Notification notification = new Notification(
R.drawable.ic_launcher, "This is ticker text",
System.currentTimeMillis());
Uri soundUri = Uri.fromFile(new File("/system/media/audio/ringtones/Basic_tone.ogg"));
notification.sound = soundUri;
long[] vibrates = {0, 1000, 1000, 1000};
notification.vibrate = vibrates;
notification.ledARGB = Color.GREEN;
notification.ledOnMS = 1000;
notification.ledOffMS = 1000;
notification.flags = Notification.FLAG_SHOW_LIGHTS;
//			notification.defaults = Notification.DEFAULT_ALL;
Intent intent = new Intent(this, NotificationActivity.class);
PendingIntent pi = PendingIntent.getActivity(this, 0, intent,
PendingIntent.FLAG_CANCEL_CURRENT);
notification.setLatestEventInfo(this, "This is content title",
"This is content text", pi);
manager.notify(1, notification);
break;
default:
break;
}
}

}

点击按钮后，会跳转另一个activity,并关闭通知

public class NotificationActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.notification_layout);
NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
manager.cancel(1);
}

}

接收和发送短信

接收短信

当手机接收到一条短信的时候，系统会发出一条值为android.provider.Telephony.SMS_RECEIVED的广播，这条广播里携带的与短信相关的数据。每个应用程序都可以在广播接收器里对它进行监听，收到广播解析出短信的内容即可。

class MessageReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
Bundle bundle = intent.getExtras();
Object[] pdus = (Object[]) bundle.get("pdus");
SmsMessage[] messages = new SmsMessage[pdus.length];
for (int i = 0; i < messages.length; i++) {
messages[i] = SmsMessage.createFromPdu((byte[]) pdus[i]);
}
String address = messages[0].getOriginatingAddress();
String fullMessage = "";
for (SmsMessage message : messages) {
fullMessage += message.getMessageBody();
}
sender.setText(address);
content.setText(fullMessage);
abortBroadcast();
}

}

首先从intent参数中取出一个Bundle对象，然后使用pdu密钥来提取SMS pdus数组，其中每一个pdu都表示一条短消息。接着使用SmsMessage的createfromPdu()方法将每一个pdu字节数组转化为SmsMessage对象，调用这个对象的getOriginatingAddress()方法就可以获取到短信的发送方号码，调用getMessageBody()方法就可以获取短信的内容。最后将方法和内容显示在textview中。

完成之后，需要对它进行注册才能让他接收到短信广播。使用动态广播注册，在onCreate()注册，在onDesstroy()进行注销。当然还要添加权限。

发送短信与接收短信类似，发送时调用SmsManager()的getDefault()方法获取到SmsManager的实例，然后调用它的sendTextMessage()方法就可以去发送短线了。

sendTextMessage()方法接受五个参数，其中第一个参数用于指定接收人的手机号码，第三个参数用于指定短信的内容，其他暂时传入NULL。

PendingIntent的getBroadcast(）方法获取一个PendingIntent对象，并将它作为第四个参数传递到sendTextMessage()方法中。然后注册一个新的广播接收器SendStatusReceiver,其专门用于监听短信发送状态，当getResultCode()的值等于RESULT_OK就会提示发送成功，否则提示发送失败。

public class MainActivity extends Activity {

private TextView sender;

private TextView content;

private EditText to;

private EditText msgInput;

private Button send;

private IntentFilter receiveFilter;

private MessageReceiver messageReceiver;

private IntentFilter sendFilter;

private SendStatusReceiver sendStatusReceiver;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sender = (TextView) findViewById(R.id.sender);
content = (TextView) findViewById(R.id.content);
to = (EditText) findViewById(R.id.to);
msgInput = (EditText) findViewById(R.id.msg_input);
send = (Button) findViewById(R.id.send);
receiveFilter = new IntentFilter();
receiveFilter.addAction("android.provider.Telephony.SMS_RECEIVED");
receiveFilter.setPriority(100);
messageReceiver = new MessageReceiver();
registerReceiver(messageReceiver, receiveFilter);
sendFilter = new IntentFilter();
sendFilter.addAction("SENT_SMS_ACTION");
sendStatusReceiver = new SendStatusReceiver();
registerReceiver(sendStatusReceiver, sendFilter);
send.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
SmsManager smsManager = SmsManager.getDefault();
Intent sentIntent = new Intent("SENT_SMS_ACTION");
PendingIntent pi = PendingIntent.getBroadcast(
MainActivity.this, 0, sentIntent, 0);
smsManager.sendTextMessage(to.getText().toString(), null,
msgInput.getText().toString(), pi, null);
}
});
}

@Override
protected void onDestroy() {
super.onDestroy();
unregisterReceiver(messageReceiver);
unregisterReceiver(sendStatusReceiver);
}

class MessageReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
Bundle bundle = intent.getExtras();
Object[] pdus = (Object[]) bundle.get("pdus");
SmsMessage[] messages = new SmsMessage[pdus.length];
for (int i = 0; i < messages.length; i++) {
messages[i] = SmsMessage.createFromPdu((byte[]) pdus[i]);
}
String address = messages[0].getOriginatingAddress();
String fullMessage = "";
for (SmsMessage message : messages) {
fullMessage += message.getMessageBody();
}
sender.setText(address);
content.setText(fullMessage);
abortBroadcast();
}

}

class SendStatusReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
if (getResultCode() == RESULT_OK) {
Toast.makeText(context, "Send succeeded", Toast.LENGTH_LONG)
.show();
} else {
Toast.makeText(context, "Send failed", Toast.LENGTH_LONG)
.show();
}
}

}

}

调用摄像头和相册

调用摄像头拍照

public class MainActivity extends Activity {

public static final int TAKE_PHOTO = 1;

public static final int CROP_PHOTO = 2;

private Button takePhoto;

private Button chooseFromAlbum;

private ImageView picture;

private Uri imageUri;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
takePhoto = (Button) findViewById(R.id.take_photo);
chooseFromAlbum = (Button) findViewById(R.id.choose_from_album);
picture = (ImageView) findViewById(R.id.picture);
takePhoto.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
File outputImage = new File(Environment.getExternalStorageDirectory(),
"output_image.jpg");
try {
if (outputImage.exists()) {
outputImage.delete();
}
outputImage.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
imageUri = Uri.fromFile(outputImage);
Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
startActivityForResult(intent, TAKE_PHOTO);
}
});
chooseFromAlbum.setOnClickListener(new OnClickListener() {//用于从相册中选择图片 未完成
@Override
public void onClick(View v) {
File outputImage = new File(Environment.getExternalStorageDirectory(),
"output_image.jpg");
try {
if (outputImage.exists()) {
outputImage.delete();
}
outputImage.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
imageUri = Uri.fromFile(outputImage);
Intent intent = new Intent("android.intent.action.GET_CONTENT");
intent.setType("image/*");
intent.putExtra("crop", true);
intent.putExtra("scale", true);
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
startActivityForResult(intent, CROP_PHOTO);
}
});
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
case TAKE_PHOTO:
if (resultCode == RESULT_OK) {
Intent intent = new Intent("com.android.camera.action.CROP");
intent.setDataAndType(imageUri, "image/*");
intent.putExtra("scale", true);
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
startActivityForResult(intent, CROP_PHOTO);
}
break;
case CROP_PHOTO:
if (resultCode == RESULT_OK) {
try {
Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver()
.openInputStream(imageUri));
picture.setImageBitmap(bitmap);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
break;
default:
break;
}
}

}

播放多媒体文件

播放音频

public class MainActivity extends Activity implements OnClickListener {

private Button play;

private Button pause;

private Button stop;

private MediaPlayer mediaPlayer = new MediaPlayer();

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
play = (Button) findViewById(R.id.play);
pause = (Button) findViewById(R.id.pause);
stop = (Button) findViewById(R.id.stop);
play.setOnClickListener(this);
pause.setOnClickListener(this);
stop.setOnClickListener(this);
initMediaPlayer();
}

private void initMediaPlayer() {
try {
File file = new File(Environment.getExternalStorageDirectory(), "music.mp3");
mediaPlayer.setDataSource(file.getPath());
mediaPlayer.prepare();
} catch (Exception e) {
e.printStackTrace();
}
}

@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.play:
if (!mediaPlayer.isPlaying()) {
mediaPlayer.start();
}
break;
case R.id.pause:
if (mediaPlayer.isPlaying()) {
mediaPlayer.pause();
}
break;
case R.id.stop:
if (mediaPlayer.isPlaying()) {
mediaPlayer.reset();
initMediaPlayer();
}
break;
default:
break;
}
}

@Override
protected void onDestroy() {
super.onDestroy();
if (mediaPlayer != null) {
mediaPlayer.stop();
mediaPlayer.release();
}
}

}

播放视频文件

public class MainActivity extends Activity implements OnClickListener {

private VideoView videoView;

private Button play;

private Button pause;

private Button replay;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
play = (Button) findViewById(R.id.play);
pause = (Button) findViewById(R.id.pause);
replay = (Button) findViewById(R.id.replay);
videoView = (VideoView) findViewById(R.id.video_view);
play.setOnClickListener(this);
pause.setOnClickListener(this);
replay.setOnClickListener(this);
initVideoPath();
}

private void initVideoPath() {
File file = new File(Environment.getExternalStorageDirectory(), "movie.3gp");
videoView.setVideoPath(file.getPath());
}

@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.play:
if (!videoView.isPlaying()) {
videoView.start();
}
break;
case R.id.pause:
if (videoView.isPlaying()) {
videoView.pause();
}
break;
case R.id.replay:
if (videoView.isPlaying()) {
videoView.resume();
}
break;
}
}

@Override
protected void onDestroy() {
super.onDestroy();
if (videoView != null) {
videoView.suspend();
}
}

}