上傳圖片功能實現
1.如果沒有相機許可權,申請開啟相機許可權
if (!ActivityCompat.shouldShowRequestPermissionRationale(this,Manifest.permission.CAMERA)){
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA},0);
}
2.如果相機許可權被關閉提示開啟許可權
if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) { //申請WRITE_EXTERNAL_STORAGE許可權 Toast.makeText(this,"請開啟相機許可權",Toast.LENGTH_SHORT).show(); return; }
3.startActivityForResult的使用方法
使用startActivityForResult(Intent intent, int requestCode)方法傳入一個請求碼(第二個引數)。請求碼相當於一個識別符號,根據不同的識別符號可以在onActivityResult中實現不同的邏輯處理。例如以下程式碼:
@Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { switch (requestCode) { case PHOTO_REQUEST_CAREMA: 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); // 啟動裁剪程式 } 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; case ARRAY_PHOTO: if (resultCode == RESULT_OK) { try { if(data != null) { Uri uri = data.getData(); imageUri = uri; } Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver() .openInputStream(imageUri)); picture.setImageBitmap(bitmap); } catch (FileNotFoundException e) { e.printStackTrace(); } } break; default: super.onActivityResult(requestCode, resultCode, data); break; } }
在以上onActivityResult方法中,根據startActivityForResult中傳入requestCode的不同實現不同的功能,例如以下程式碼傳入requestCode == ARRAY_PHOTO。
public void openGallery() {
Intent intent = new Intent(Intent.ACTION_PICK);
intent.setType("image/*");
startActivityForResult(intent, ARRAY_PHOTO);
}
4.Enviroment類使用方法
其主要方法有:
getRootDirectory()---->/ 獲取根目錄
getDataDirectory()---->/data 獲取data目錄
getExternalStorageDirectory()—>/sdcard 獲取sd卡目錄
getDownloadCacheDirectory()—>/cache 獲取下載檔案的快取目錄
getExternalStorageState—>sdcard的狀態,removed,unmounted,checking,nofs,mounted,mounted_ro,shared,unmountable,bad_removal
5.ContentResolver類使用方法
ContentResolver提供的方法和ContentProvider提供的方法對應的有以下幾個方法。
public Uri insert(Uri uri, ContentValues values) 用於新增資料到指定Uri的ContentProvider中。
public int delete(Uri uri, String selection, String[] selectionArgs) 用於從指定Uri的ContentProvider中刪除資料。
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) 用於更新指定Uri的ContentProvider中的資料。
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) 用於查詢指定Uri的ContentProvider。
6.上傳圖片、從相簿選擇照片以及圖片裁剪功能實現
首先建立PhotoActivity類
public class PhotoActivity extends AppCompatActivity implements View.OnClickListener {
public static final int PHOTO_REQUEST_CAREMA = 1;// 拍照
public static final int CROP_PHOTO = 2;// 裁剪
public static final int ARRAY_PHOTO = 3;// 相簿選取
private Button takePhoto;
private ImageView picture;
private Uri imageUri;
public static File tempFile;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.photo);
takePhoto = (Button) findViewById(R.id.take_photo);
picture = (ImageView) findViewById(R.id.picture);
takePhoto.setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.take_photo:
if (!ActivityCompat.shouldShowRequestPermissionRationale(this,Manifest.permission.CAMERA)){
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA},0);
}
if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA)
!= PackageManager.PERMISSION_GRANTED) {
//申請WRITE_EXTERNAL_STORAGE許可權
//Util.showToast(this,"請開啟相機許可權");
Toast.makeText(this,"請開啟相機許可權",Toast.LENGTH_SHORT).show();
return;
}
openCamera(this);//拍照獲取照片
//openGallery();//從相簿選擇照片
break;
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
case PHOTO_REQUEST_CAREMA:
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); // 啟動裁剪程式
}
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;
case ARRAY_PHOTO:
if (resultCode == RESULT_OK) {
try {
if(data != null) {
Uri uri = data.getData();
imageUri = uri;
}
Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver()
.openInputStream(imageUri));
picture.setImageBitmap(bitmap);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
break;
default:
super.onActivityResult(requestCode, resultCode, data);
break;
}
}
public void openCamera(Activity activity) {
//獲取系統版本
int currentapiVersion = android.os.Build.VERSION.SDK_INT;
// 啟用相機
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
// 判斷儲存卡是否可以用,可用進行儲存
if (hasSdcard()) {
SimpleDateFormat timeStampFormat = new SimpleDateFormat(
"yyyy_MM_dd_HH_mm_ss");
String filename = timeStampFormat.format(new Date());
tempFile = new File(Environment.getExternalStorageDirectory(),
filename + ".jpg");
if (currentapiVersion < 24) {
// 從檔案中建立uri
imageUri = Uri.fromFile(tempFile);
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
} else {
//相容android7.0 使用共享檔案的形式
ContentValues contentValues = new ContentValues(1);
contentValues.put(MediaStore.Images.Media.DATA, tempFile.getAbsolutePath());
//檢查是否有儲存許可權,以免崩潰
if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
!= PackageManager.PERMISSION_GRANTED) {
//申請WRITE_EXTERNAL_STORAGE許可權
//Util.showToast(this,"請開啟儲存許可權");
Toast.makeText(this,"請開啟儲存許可權",Toast.LENGTH_SHORT).show();
return;
}
imageUri = activity.getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, contentValues);
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
}
}
// 開啟一個帶有返回值的Activity,請求碼為PHOTO_REQUEST_CAREMA
activity.startActivityForResult(intent, PHOTO_REQUEST_CAREMA);
}
/*
* 判斷sdcard是否被掛載
*/
public static boolean hasSdcard() {
return Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED);
}
public void openGallery() {
Intent intent = new Intent(Intent.ACTION_PICK);
intent.setType("image/*");
startActivityForResult(intent, ARRAY_PHOTO);
}
}
然後建立對應的photo.xml檔案
<?xml version="1.0" encoding="utf-8"?>
<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" />
<ImageView
android:id="@+id/picture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal" />
</LinearLayout>