安卓学习笔记（八）运用手机多媒体
总结《第一行代码》Android学习笔记（八）运用手机多媒体
- 运用手机多媒体
- 通知（Notification）
- 调用摄像头和相册
- 播放多媒体文件
- 播放音频
- 播放视频
运用手机多媒体
通知（Notification）
例如我们想要实现点击按钮后弹出通知然后点击通知后跳转到一个新的界面的话，我们就需要使用Notification。
首先需要新建一个NotificationManager来管理通知，我们调用Context的getSystemService()方法并传入通知服务参数后获得NotificationManager实例，然后我们需要一个Builder来创建Notification对象，接着连缀各种设置方法来对Notification对象进行设置，最后不要忘了使用build()方法创建Notification并且调用NotificationManager的notify()方法来让通知显示出来。
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button sendNotice = findViewById(R.id.send_notice);
sendNotice.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this,NotificationActivity.class);//建立跳转的意图
PendingIntent pi = PendingIntent.getActivity(MainActivity.this,0,intent,0);//将意图对象传入PendingIntent的getActivity方法以得到PendingIntent实例
NotificationManager manager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);//创建NotificationManager
Notification notification = new NotificationCompat.Builder(MainActivity.this)//创建Notification对象
.setContentTitle("This is content title")//指定通知标题内容
.setContentText("This is content text.")//指定通知正文内容
.setWhen(System.currentTimeMillis())//指定通知被创建时间
.setSmallIcon(R.mipmap.ic_launcher)//设置通知的小图标
.setLargeIcon(BitmapFactory.decodeResource(getResources(),R.mipmap.ic_launcher))//设置通知的大图标
.setContentIntent(pi)//点击通知跳转到NotificationActivity
.setAutoCancel(true)//点击通知后通知消失
// .setSound(Uri.fromFile(new File(Environment.getExternalStorageDirectory(),"music.mp3")))//设置通知音频
// .setVibrate(new long[] {0,1000,1000,1000})//设置立即振动1s,静止1s,再振动1s
// .setLights(Color.WHITE,1000,1000)//设置提示灯
.setDefaults(NotificationCompat.DEFAULT_ALL)//直接使用通知默认效果
// .setStyle(new NotificationCompat.BigTextStyle().bigText("This is content text.This is content text.This is content text.This is content text."))//显示长文字
.setStyle(new NotificationCompat.BigPictureStyle().bigPicture(BitmapFactory.decodeResource(getResources(),R.drawable.image2)))//显示大图
.setPriority(NotificationCompat.PRIORITY_MAX)//设置通知的重要程度
.build();
manager.notify(1,notification);//显示通知
}
});
}
}
调用摄像头和相册
MainActivity.java：
public class MainActivity extends AppCompatActivity {
public static final int TAKE_PHOTO = 1;
public static final int CHOOSE_PHOTO = 2;
private ImageView picture;
private Uri imageUri;
private static final String TAG = "MainActivity";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button takePhoto = findViewById(R.id.take_photo);
Button chooseFromAlbum = findViewById(R.id.choose_from_album);
picture = findViewById(R.id.picture);
takePhoto.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//创建File对象，用于存储拍照后的图片
File outputImage = new File(getExternalCacheDir(),"output_image.jpg");
try{
if(outputImage.exists()){
outputImage.delete();
}
outputImage.createNewFile();
}catch (IOException e){
e.printStackTrace();
}
if(Build.VERSION.SDK_INT >= 24){
imageUri = FileProvider.getUriForFile(MainActivity.this,"com.example.youyu4.cameraalbumtest.fileprovider",outputImage);
}else{
imageUri = Uri.fromFile(outputImage);
}
//启动相机程序
Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
intent.putExtra(MediaStore.EXTRA_OUTPUT,imageUri);
startActivityForResult(intent,TAKE_PHOTO);
}
});
chooseFromAlbum.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if(ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
}else{
openAlbum();
}
}
});
}
private void openAlbum(){
Intent intent = new Intent("android.intent.action.GET_CONTENT");
intent.setType("image/*");
startActivityForResult(intent,CHOOSE_PHOTO);//打开相册
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
switch (requestCode){
case 1:
if(grantResults.length >= 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
openAlbum();
}else{
Toast.makeText(this, "You denied the permission", Toast.LENGTH_SHORT).show();
}
break;
default:
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
switch (requestCode){
case TAKE_PHOTO:
if(resultCode == RESULT_OK){
try{
//将拍摄的图片显示出来
Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
picture.setImageBitmap(bitmap);
}catch (FileNotFoundException e){
e.printStackTrace();
}
}
break;
case CHOOSE_PHOTO:
if (resultCode == RESULT_OK){
//判断手机系统版本号
if(Build.VERSION.SDK_INT >= 19){
//4.4及以上系统使用这个方法处理图片
handleImageOnKitKat(data);
}else{
//4.4以下系统使用这个方法处理图片
handleImageforeKitKat(data);
}
}
break;
default:
break;
}
}
@TargetApi(19)
private void handleImageOnKitKat(Intent data){
String imagePath = null;
Uri uri =data.getData();
if(DocumentsContract.isDocumentUri(this,uri)){
//如果是document类型的Uri，则通过document id处理
String docId = DocumentsContract.getDocumentId(uri);
if("com.android.providers.media.documents".equals(uri.getAuthority())){
String id = docId.split(":")[1];//解析出数字格式的id
String selection = MediaStore.Images.Media._ID + "=" + id;
imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,selection);
}else if("com.android.providers.downloads.documents".equals(uri.getAuthority())){
Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"),Long.valueOf(docId));
imagePath = getImagePath(contentUri,null);
}
}else if("content".equalsIgnoreCase(uri.getScheme())){
//如果是content类型的Uri,直接使用普通方式处理
imagePath = getImagePath(uri,null);
}else if("file".equalsIgnoreCase(uri.getScheme())){
//如果是file类型的Uri，直接获取图片路径即可
imagePath = uri.getPath();
}
displayImage(imagePath);
}
private void handleImageforeKitKat(Intent data){
Uri uri = data.getData();
String imagePath = getImagePath(uri,null);
displayImage(imagePath);
}
private String getImagePath(Uri uri,String selection){
String path = null;
//通过Uri和selection来获取真实的图片路径
Cursor cursor = getContentResolver().query(uri,null,selection,null,null);
if(cursor != null){
if(cursor.moveToNext()){
path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
}
cursor.close();
}
return path;
}
private void displayImage(String imagePath){
if(imagePath != null){
Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
picture.setImageBitmap(bitmap);
}else{
Toast.makeText(this,"failed to get image",Toast.LENGTH_SHORT).show();
}
}
}
AndroidManifest.xml：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.youyu4.cameraalbumtest">
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
intent-filter>
activity>
<provider
android:authorities="com.example.youyu4.cameraalbumtest.fileprovider"
android:name="androidx.core.content.FileProvider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_paths"/>
provider>
application>
manifest>
播放多媒体文件
播放音频
播放音频项目的布局文件主要包含三个按钮分别控制音频的播放、暂停和停止，编写MainActivity.java：
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private MediaPlayer mediaPlayer = new MediaPlayer();
private static final String TAG = "MainActivity";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button play = findViewById(R.id.play);
Button pause = findViewById(R.id.pause);
Button stop = findViewById(R.id.stop);
play.setOnClickListener(this);
pause.setOnClickListener(this);
stop.setOnClickListener(this);
if(ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
}else{
initMediaPlayer();//初始化MediaPlayer
}
}
private void initMediaPlayer(){
try{
File file = new File(Environment.getExternalStorageDirectory(),"music.mp3");
Log.i("aaa", file.getPath());
mediaPlayer.setDataSource(file.getPath());//指定音频文件的路径
mediaPlayer.prepare();//让MediaPlayer进入准备状态
}catch (Exception e){
e.printStackTrace();
}
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
switch (requestCode){
case 1:
if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
initMediaPlayer();
}else{
Toast.makeText(this,"拒绝权限将无法使用程序",Toast.LENGTH_SHORT).show();
finish();
}
break;
default:
}
}
@Override
public void onClick(View view) {
switch (view.getId()){
case R.id.play:
if(!mediaPlayer.isPlaying()){
mediaPlayer.start();//开始播放
}
break;
case R.id.pause:
if(mediaPlayer.isPlaying()){
mediaPlayer.pause();//暂停播放
}
break;
case R.id.stop:
if(mediaPlayer.isPlaying()){
mediaPlayer.reset();//停止播放
initMediaPlayer();
}
break;
default:
break;
}
}
@Override
protected void onDestroy() {
super.onDestroy();
if(mediaPlayer != null){
mediaPlayer.stop();
mediaPlayer.release();
}
}
}
最后不要忘了在AndroidManifest中声明读写sd卡的权限：
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
播放视频
播放视频项目的布局文件包含三个按钮和一个VideoView，按钮用于控制视频的播放、暂停和重新播放，VideoView用于显示视频，修改MainActivity：
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private static final String TAG = "MainActivity";
private VideoView videoView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
videoView = findViewById(R.id.video_view);
Button play = findViewById(R.id.play);
Button pause = findViewById(R.id.pause);
Button replay = findViewById(R.id.replay);
play.setOnClickListener(this);
pause.setOnClickListener(this);
replay.setOnClickListener(this);
if(ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
}else{
initVideoPath();//初始化VideoView
}
}
private void initVideoPath(){
File file = new File(Environment.getExternalStorageDirectory(),"movie.mp4");
videoView.setVideoPath(file.getPath());//指定视频文件的路劲
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
switch (requestCode){
case 1:
if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
initVideoPath();
}else {
Toast.makeText(this,"拒绝权限将无法使用程序",Toast.LENGTH_SHORT).show();
finish();
}
break;
default:
}
}
@Override
public void onClick(View view) {
switch (view.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();
}
}
}
最后不要忘了在AndroidManifest中声明读写sd卡的权限：
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>