调用摄像头拍照
修改布局文件中代码：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="@+id/take_photo"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Take Photo"/> //用来打开摄像头进行拍照
<ImageView
android:id="@+id/picture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"/> //将拍到的图片显示出来
</LinearLayout>编写调用摄像头的具体逻辑。修改活动文件：
public class MainActivity extends AppCompatActivity {
public static final int TAKE_PHOTO = 1;
private ImageView picture;
private Uri imageUri;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button takePhoto = (Button) findViewById(R.id.take_photo);
picture = (ImageView) findViewById(R.id.picture);
takePhoto.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View v){
File outputImage = new File(getExternalCacheDir(),"output_image.jpg"); //创建了一个File对象，用于存放摄像头拍下的图片，并将它保存在SD卡的应用缓存目录下，用getExternalCacheDir（）得到目录
try{
if(outputImage.exists()){
outputImage.delete();
}
outputImage.createNewFile();
}catch (IOException e) {
e.printStackTrace();
}
if(Build.VERSION.SDK_INT>=24){ //若设备系统版本低于Android7.0，就调用Uri的fromFile（）将File对象转换成Uri对象(表示着图片的本地真实路径)
imageUri = FileProvider.getUriForFile(MainActivity.this,"com/example.cameraalbumtest.fileprovider",outputImage);//否则就调用FileProvider的getUriForFile（）
}else{
imageUri = Uri.fromFile(outputImage); 方法将File对象转换成一个封装过的Uri对象
}
Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");//将这个Intent的action指定为android.media.action.IMAGE_CAPTURE
intent.putExtra(MediaStore.EXTRA_OUTPUT,imageUri);//置顶图片的输出地址
startActivityForResult(intent,RAKE_PHOTO);
}
});
}
@Override
protected void onActivityResult(int requestCode,int resultCode, Intent data){ //用startActivityForResult（）启动活动会有结果返回到此方法中
switch (requestCode){
case TAKE_PHOTO:
if(resultCode == RESULT_OK){
try{
//将拍摄的照片显示出来
Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream((imageUri));
picture.setImageBitmap(bitmap);
}catch (FileNotFoundException e){
e.printStackTrace();
}
}
break;
default:
break;
}
}
}在AndroidMainfest.xml中对内容提供器（FileProvider）进行注册：
<provider
android:authorities="com.example.cameraalbumtest.fileprovider" //必须和干菜FileProvider.getUriForFile（）方法中第二个参数一致
android:name="android.support.v4.content.FileProvider" //此属性值是固定的
android:exported="false"
android:grantUriPermissions="true">
<meta-data //用<meta-data>来指定Uri的共享路径，并引用了一个@xml/file_path资源（下面我们来创建）
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_paths"/>
</provider>创建上面说的@xml/file_path资源
<?xml version="1.0" encoding="utf-8" ?>
<paths xmlns:andriod="http://schemas.android.com/apk/res/android">
<enternal-path name="my_images" path=""/> //用来指定Uri共享，name属性值可以随便填，path属性的指标是共享的具体路径，此处为空表示共
</paths> //享整个SD卡在Android4.4之前，需要声明权限：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.cameraalbumtest">
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>从相册中选择照片
在上面的基础上在布局文件中添加：
<Button
android:id="@+id/choose_from_album"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""Choose From Album/>然后修改MainActivity文件中代码，加入从相册选择照片的逻辑：（红色为新增）
public class MainActivity extends AppCompatActivity {
public static final int TAKE_PHOTO = 1;
private ImageView picture;
private Uri imageUri;
public static final int CHOOSE_PHOTO = 2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button takePhoto = (Button) findViewById(R.id.take_photo);
Button chooseFromAlbum = (Button) findViewById(R.id.choose_from_album);
picture = (ImageView) findViewById(R.id.picture);
takePhoto.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
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.cameraalbumtest.fileprovider", outputImage);
} else {
imageUri = Uri.fromFile(outputImage);
}
Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
startActivityForResult(intent, RAKE_PHOTO);
}
});
chooseFromAlbum.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) { //申请权限
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");//将他的action指定为“”中的
intent.setType("image/*");
startActivityForResult(intent, CHOOSE_PHOTO); //打开相册。第二个参数值为CHOOSE_PHOTO，
} //当从相册选择完图片回到onActivityResult方法时，就会进入CHOOSE_PHOTO的case来处理图片
@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, 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, Intent data){
switch (requestCode){
case TAKE_PHOTO:
if(resultCode == RESULT_OK){
try{
//将拍摄的照片显示出来
Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
picture.setImageBitmap(bitmap);
}catch (FileNotFoundException e){
e.printStackTrace();
}
}
break;
case CHOOSE_PHOTO:
if(resultCode == RESULT_OK) {
if (Build.VERSION.SDK_INT >= 19) { //进行版本判断
handleImageOnKitKat(data);
} else {
handleImageBeforeKitKat(data);
}
}
break;
default:
break;
}
}
@Target(19)
private void handleImageOnKitKat(Intent data) { //如何解析这个封装过的Uri
String imagePath = null;
Uri uri = data.getData();
if( DocumentsContract.isDocumentUri(this,Uri)){
String docId = DocumentsContract.getDocumentId(uri);
if ("com.android.providers.media.documents".equals(uri.getAuthority())){
String id = docId.split(":")[1];
String selection = MediaStore.Images.Media._ID + "=" + id;
imagePath = getImagePath(MediaStore.Inages.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())){
imagePath = getImagePath(uri,null);
}else if ("file".equalsIgnoreCase(uri.getScheme())){
imagePath = uri.getPath();
}
displayImage(imagePath);
}
private void handleImageBeforeKitKat(Intent data) {
Uri uri = data.getData();
String imagePath = getImagePath(rui,null);
displayImage(imagePath);
}
private String getImagePath(Uri uri,String selection){
String path = null;
Cursor cursor = getContentResolver().query(uri,null,selection,null,null);
if(cursor != null){
if(cursor.moveToFirst()){
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();
}
}
}应该有错，不过可以根据报错修改