Android學習之呼叫相機和相簿
阿新 • • 發佈：2018-12-06
呼叫攝像頭拍照
修改佈局檔案中程式碼：
<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"/> //用來開啟攝像頭進行拍照 <ImageView android:id="@+id/picture" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal"/> //將拍到的圖片顯示出來 </LinearLayout>
編寫呼叫攝像頭的具體邏輯。修改活動檔案：
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"); //建立了一個File物件，用於存放攝像頭拍下的圖片，並將它儲存在SD卡的應用快取目錄下，用getExternalCacheDir（）得到目錄 try{ if(outputImage.exists()){ outputImage.delete(); } outputImage.createNewFile(); }catch (IOException e) { e.printStackTrace(); } if(Build.VERSION.SDK_INT>=24){ //若裝置系統版本低於Android7.0，就呼叫Uri的fromFile（）將File物件轉換成Uri物件(表示著圖片的本地真實路徑) imageUri = FileProvider.getUriForFile(MainActivity.this,"com/example.cameraalbumtest.fileprovider",outputImage);//否則就呼叫FileProvider的getUriForFile（） }else{ imageUri = Uri.fromFile(outputImage); 方法將File物件轉換成一個封裝過的Uri物件 } Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");//將這個Intent的action指定為android.media.action.IMAGE_CAPTURE intent.putExtra(MediaStore.EXTRA_OUTPUT,imageUri);//置頂圖片的輸出地址 startActivityForResult(intent,RAKE_PHOTO); } }); } @Override protected void onActivityResult(int requestCode,int resultCode, Intent data){ //用startActivityForResult（）啟動活動會有結果返回到此方法中 switch (requestCode){ case TAKE_PHOTO: if(resultCode == RESULT_OK){ try{ //將拍攝的照片顯示出來 Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream((imageUri)); picture.setImageBitmap(bitmap); }catch (FileNotFoundException e){ e.printStackTrace(); } } break; default: break; } } }
在AndroidMainfest.xml中對內容提供器（FileProvider）進行註冊：
<provider android:authorities="com.example.cameraalbumtest.fileprovider" //必須和乾菜FileProvider.getUriForFile（）方法中第二個引數一致 android:name="android.support.v4.content.FileProvider" //此屬性值是固定的 android:exported="false" android:grantUriPermissions="true"> <meta-data //用<meta-data>來指定Uri的共享路徑，並引用了一個@xml/file_path資源（下面我們來建立） android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/file_paths"/> </provider>
建立上面說的@xml/file_path資源
<?xml version="1.0" encoding="utf-8" ?>
<paths xmlns:andriod="http://schemas.android.com/apk/res/android">
<enternal-path name="my_images" path=""/> //用來指定Uri共享，name屬性值可以隨便填，path屬性的指標是共享的具體路徑，此處為空表示共
</paths> //享整個SD卡在Android4.4之前，需要宣告許可權：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.cameraalbumtest">
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>從相簿中選擇照片
在上面的基礎上在佈局檔案中新增：
<Button
android:id="@+id/choose_from_album"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""Choose From Album/>然後修改MainActivity檔案中程式碼，加入從相簿選擇照片的邏輯：（紅色為新增）
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) { //申請許可權
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");//將他的action指定為“”中的
intent.setType("image/*");
startActivityForResult(intent, CHOOSE_PHOTO); //開啟相簿。第二個引數值為CHOOSE_PHOTO，
} //當從相簿選擇完圖片回到onActivityResult方法時，就會進入CHOOSE_PHOTO的case來處理圖片
@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{
//將拍攝的照片顯示出來
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) { //進行版本判斷
handleImageOnKitKat(data);
} else {
handleImageBeforeKitKat(data);
}
}
break;
default:
break;
}
}
@Target(19)
private void handleImageOnKitKat(Intent data) { //如何解析這個封裝過的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();
}
}
}應該有錯，不過可以根據報錯修改